And it's not even for the Dept. of Defense! :-)

For those of you thinking about airplane ownership (and I know you're
lurking out there!), we just got the bill to replace one of the two dimmer
switches (and a few light bulbs) in our Pathfinder's panel.

$104 in parts, 5 hours labor (It's a real bitch to diagnose and get at in a
Cherokee...).

Total: $429.73.

Gotta love aviation.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

> And it's not even for the Dept. of Defense! :-)
>
> For those of you thinking about airplane ownership (and I know you're
> lurking out there!), we just got the bill to replace one of the two dimmer
> switches (and a few light bulbs) in our Pathfinder's panel.
>
> $104 in parts, 5 hours labor (It's a real bitch to diagnose and get at in
a
> Cherokee...).
>
> Total: $429.73.
>
> Gotta love aviation.

Get in there and do that kind of thing yourself and pay somebody to check it
and sign it off !

And you still refuse to learn how to use a multimeter and get your hands dirty?

Sheesh. There is no hope.

{;-)

Jim



"Jay Honeck" >
shared these priceless pearls of wisdom:

->And it's not even for the Dept. of Defense! :-)
->
->For those of you thinking about airplane ownership (and I know you're
->lurking out there!), we just got the bill to replace one of the two dimmer
->switches (and a few light bulbs) in our Pathfinder's panel.
->
->$104 in parts, 5 hours labor (It's a real bitch to diagnose and get at in a
->Cherokee...).
->
->Total: $429.73.
->
->Gotta love aviation.

Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

> Get in there and do that kind of thing yourself and pay somebody to check
it
> and sign it off !

Um, well, it took quite a while to determine that it was a problem with the
dimmer itself.

The circuitry for this thing is just totally bizarre. Rather than just
being a simple rheostat, it's hooked into some transistors, and capacitors,
and resistors -- all for no apparent reason. At first the shop thought it
was one of the transistors, but it blew instantly when they installed a new
one (at no charge to me), so they had to keep digging.

Mumble, grumble. Stupid 30 year old planes. I'm sure the new Cirrus panel
has everything in the dimmer circuit on a single chip, hidden somewhere in
the armrest, or something.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

> Mumble, grumble. Stupid 30 year old planes. I'm sure the new Cirrus
panel
> has everything in the dimmer circuit on a single chip, hidden somewhere in
> the armrest, or something.
> --

Naw, the FAA probably still requires the same "proven" circuit that is in
your plane.

Err, that transistor is there so that the rheostat doesn't double as a space
heater. It is there for a very good reason, although today there are better
ways to dim rather than a pass transistor. For that price, you could have
installed one of the pulse width modulated dimmers and done away with the old
fashioned piper circuit. Would have required a 337, but then it would be the
last time you'd ever have to deal with it. You might have even been able to
get separate dimmer circuits for instrument and overhead lights out of the
deal.

Jay Honeck wrote:

> > Get in there and do that kind of thing yourself and pay somebody to check
> it
> > and sign it off !
>
> Um, well, it took quite a while to determine that it was a problem with the
> dimmer itself.
>
> The circuitry for this thing is just totally bizarre. Rather than just
> being a simple rheostat, it's hooked into some transistors, and capacitors,
> and resistors -- all for no apparent reason. At first the shop thought it
> was one of the transistors, but it blew instantly when they installed a new
> one (at no charge to me), so they had to keep digging.
>
> Mumble, grumble. Stupid 30 year old planes. I'm sure the new Cirrus panel
> has everything in the dimmer circuit on a single chip, hidden somewhere in
> the armrest, or something.
> --
> Jay Honeck
> Iowa City, IA
> Pathfinder N56993
> www.AlexisParkInn.com
> "Your Aviation Destination"

--
--Ray Andraka, P.E.
President, the Andraka Consulting Group, Inc.
401/884-7930 Fax 401/884-7950
email
http://www.andraka.com

"They that give up essential liberty to obtain a little
temporary safety deserve neither liberty nor safety."
-Benjamin Franklin, 1759

Jim Weir wrote:
>
> And you still refuse to learn how to use a multimeter and get your hands dirty?

The last few posts by Mr. Honeck usually contained the words "inn full" and "no
time", or similar phrases. If it took a skilled professional 5 hours to find and
fix, how long do you think it would've taken Jay to do it?

Paying the mech was probably a good deal cheaper in the short run.

George Patterson
Battle, n; A method of untying with the teeth a political knot that would
not yield to the tongue.

"Jay Honeck" > writes:

> And it's not even for the Dept. of Defense! :-)
>
> For those of you thinking about airplane ownership

Here is a test my mechanic suggested for those thinking about buying a
plane (or boat, etc).

Go to the bank and request $100 from your account. Get the cash in
the form of a crisp new $100 bill.

Go outside, and with a match or lighter set fire to the $100 bill.
Hold it in your hand and watch it burn. Throw the remainder on the
ground, grind it out, get in your car and drive away.

If this doesn't bother you in the least then you are ready to buy. If
it does, better take up some other hobby.

"Bob Fry" > wrote in message
...
> "Jay Honeck" > writes:
>
> > And it's not even for the Dept. of Defense! :-)
> >
> > For those of you thinking about airplane ownership
>
> Here is a test my mechanic suggested for those thinking about buying a
> plane (or boat, etc).
>
> Go to the bank and request $100 from your account. Get the cash in
> the form of a crisp new $100 bill.
>
> Go outside, and with a match or lighter set fire to the $100 bill.
> Hold it in your hand and watch it burn. Throw the remainder on the
> ground, grind it out, get in your car and drive away.
>
> If this doesn't bother you in the least then you are ready to buy. If
> it does, better take up some other hobby.

So...you think flying is a waste of money?

A WHAT? Read the title at the top of the 337 form. **MAJOR** repair.

Sheesh.

Jim


Ray Andraka >
shared these priceless pearls of wisdom:

- Would have required a 337,


Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

No reason, my sweet hiney. Some poor engineer that was overworked and
underfunded tried to make six components do four components work. Nothing
bizarre about it at all.

Jim


"Jay Honeck" >
shared these priceless pearls of wisdom:

->> Get in there and do that kind of thing yourself and pay somebody to check
->it
->> and sign it off !
->
->Um, well, it took quite a while to determine that it was a problem with the
->dimmer itself.
->
->The circuitry for this thing is just totally bizarre. Rather than just
->being a simple rheostat, it's hooked into some transistors, and capacitors,
->and resistors -- all for no apparent reason.



Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

You paid someone to change light bulbs?

The hotel must have a No Vacancy sign every night!

Even me, the software geek (I don't do hardware, I don't do
Windows) can change every light bulb (except 1 and that's the
bottom left on the panel) in and on the cherokee.

Tsk tsk tsk...

Now the dimmer switch is another matter entirely...

Jay Honeck > wrote:
: $104 in parts, 5 hours labor (It's a real bitch to diagnose and get at in a
: Cherokee...).

You got a good deal. I paid $179 for the right hand dimmer switch in my
Cherokee 180's panel 2 years ago. Not including installation, which broke
within 1 hour because the mechanic (1) couldn't solder and (2) had no
notion of how to properly suppport soldered wires against vibration.

--
Aaron Coolidge (N9376J)

Wouldn't replacing an approved dimmer assembly with a home-made one be a
"major alteration" that would require a Form 337, and field approval of the
data, for return to service?

"Jim Weir" > wrote in message
...
> A WHAT? Read the title at the top of the 337 form. **MAJOR** repair.
>
> Sheesh.
>
> Jim
>
>
> Ray Andraka >
> shared these priceless pearls of wisdom:
>
> - Would have required a 337,
>
>
> Jim Weir (A&P/IA, CFI, & other good alphabet soup)
> VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
> http://www.rst-engr.com

>$104 in parts, 5 hours labor (It's a real bitch to diagnose and get at in a
>Cherokee...).
>
>Total: $429.73.
>
>Gotta love aviation.

As a confirmed "lingerer" it broke my heart to hit the reply button, but as a
30+ year general aviation mechanic, ham radio hobby buff, and electronic hobby
tinkerer, I felt compelled to add my voice here. Any body that understands
that tranistorized dimming system (and its just not that complicated) SHOULD
KNOW to verify that the light chain is not shorted before sticking in a new
transistor. A short is about the only thing I've ever seen that will kill the
otherwise beefy 2N3055 transistor. I'm not trying to brag about my skills but
just stating facts.....I could have had that problem diagnosed in about 15
minutes and had the transistor changed in less than two hours....and I know
better than to try to light the lights before I correct the short in the light
chain.....'cause if ya don't.....guess what.....there goes another transistor.
Sounds like you need another mechanic...at least another one to deal with
electrical/electronic problems.

And to Mr. Weir......the 337 is for Major repair and Major ALTERATIONS. As
the chief inspector for a large repair station, if I see an aircraft for an
annual with some kind of aftermarket or home made dimmer system....it better
have a 337 associated with it....not because I'm a jerk or an a**hole, but
because that is what the regulations require. Unfortunately, if I ignore that
or miss that and the owner rolls the aircraft into a ball, even if it had
nothing to do with the accident, I could be in big trouble with the feds or
possibly be sued by the estate and loose every thing I've worked so hard for
these last 30 plus years. I've been the biz long enough to have seen that when
there is an accident with death or serious injury, the FAA and the lawyers go
after any body they can get their hooks into....and if I haven't towed the line
with the regulations, it could be implied that I have been neglegent in my job.

If you want to own and fly a certificated aircraft, then do so in accordance
with the regs, if you're a tinkerer and enjoy working on your own ship....and
more power to you, then build a home-built and any thing goes....even doing
your own yearly condition inspections.

Oh no! Someone having the audacity to disagree with King Weir!
That'll make him spit out his morning latte! Stand by for the flames.

Good points John, and I agree wholeheartedly, but can you expect every
A&P to fully understand each and every detail? I don't care to pay
for an A&P's education, but it's almost like saying that you obtained
your 30 years in a few months.


On 13 Mar 2004 12:31:27 GMT, (JohnN3TWN)
wrote:
>
>As a confirmed "lingerer" it broke my heart to hit the reply button, but as a
>30+ year general aviation mechanic, ham radio hobby buff, and electronic hobby
>tinkerer, I felt compelled to add my voice here. Any body that understands
>that tranistorized dimming system (and its just not that complicated) SHOULD
>KNOW to verify that the light chain is not shorted before sticking in a new
>transistor. A short is about the only thing I've ever seen that will kill the
>otherwise beefy 2N3055 transistor. I'm not trying to brag about my skills but
>just stating facts.....I could have had that problem diagnosed in about 15
>minutes and had the transistor changed in less than two hours....and I know
>better than to try to light the lights before I correct the short in the light
>chain.....'cause if ya don't.....guess what.....there goes another transistor.
>Sounds like you need another mechanic...at least another one to deal with
>electrical/electronic problems.
>
>And to Mr. Weir......the 337 is for Major repair and Major ALTERATIONS. As
>the chief inspector for a large repair station, if I see an aircraft for an
>annual with some kind of aftermarket or home made dimmer system....it better
>have a 337 associated with it....not because I'm a jerk or an a**hole, but
>because that is what the regulations require. Unfortunately, if I ignore that
>or miss that and the owner rolls the aircraft into a ball, even if it had
>nothing to do with the accident, I could be in big trouble with the feds or
>possibly be sued by the estate and loose every thing I've worked so hard for
>these last 30 plus years. I've been the biz long enough to have seen that when
>there is an accident with death or serious injury, the FAA and the lawyers go
>after any body they can get their hooks into....and if I haven't towed the line
>with the regulations, it could be implied that I have been neglegent in my job.
>
>If you want to own and fly a certificated aircraft, then do so in accordance
>with the regs, if you're a tinkerer and enjoy working on your own ship....and
>more power to you, then build a home-built and any thing goes....even doing
>your own yearly condition inspections.

> You paid someone to change light bulbs?

Well, not directly. They just replaced them (and the missing blue
condom-thingies that go over them) while they were there.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

> Good points John, and I agree wholeheartedly, but can you expect every
> A&P to fully understand each and every detail? I don't care to pay
> for an A&P's education, but it's almost like saying that you obtained
> your 30 years in a few months.

My A&P is the best engine and airframe man I've seen.

However, when it comes to electrical, even he will admit that he's a "figure
it as you go" guy, even though he works on DC-9s most of the time.

Personally, I think the dimmer circuitry in the Cherokee is perhaps the
dumbest thing I've seen in aviation. Even I, as a total neophyte, can see
that the system is hopelessly obtuse.

Strangely, older Cherokees had a much simpler dimmer circuit. I wonder why
Piper made it so complex later on, and I wonder if they've corrected this
mess in their new planes?
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

Jay,

I have one of those older dimmer systems, and it is no picnic. The old one is
just a power rheostat wired in with the lights. The rheostat heats up because
it handles all the power. That transistor circuit simply controls the current
by using the transistor to amplify small current changes in the rheostat. The
result is the rheostat needn't be a custom high power one, and it won't burn out
as easily. The rheostat only dimmer gets hot to the touch if you have more than
just the original overhead light and compass light on it, and probably can't
handle a full panel worth of lighting. I'd trade the simple older dimmer for
the transistorized one if it we cheap and painless to do. When my dimmer does
go, or I add more lighting to the panel, I'll probably opt for one of the pulse
width modulated ones (those are much more complicated than the piper pass
transistor, but they also dissipate very little power).

Jay Honeck wrote:

> > Good points John, and I agree wholeheartedly, but can you expect every
> > A&P to fully understand each and every detail? I don't care to pay
> > for an A&P's education, but it's almost like saying that you obtained
> > your 30 years in a few months.
>
> My A&P is the best engine and airframe man I've seen.
>
> However, when it comes to electrical, even he will admit that he's a "figure
> it as you go" guy, even though he works on DC-9s most of the time.
>
> Personally, I think the dimmer circuitry in the Cherokee is perhaps the
> dumbest thing I've seen in aviation. Even I, as a total neophyte, can see
> that the system is hopelessly obtuse.
>
> Strangely, older Cherokees had a much simpler dimmer circuit. I wonder why
> Piper made it so complex later on, and I wonder if they've corrected this
> mess in their new planes?
> --
> Jay Honeck
> Iowa City, IA
> Pathfinder N56993
> www.AlexisParkInn.com
> "Your Aviation Destination"

--
--Ray Andraka, P.E.
President, the Andraka Consulting Group, Inc.
401/884-7930 Fax 401/884-7950
email
http://www.andraka.com

"They that give up essential liberty to obtain a little
temporary safety deserve neither liberty nor safety."
-Benjamin Franklin, 1759

Ray Andraka > wrote:

> When my dimmer does go, or I add more lighting to the panel, I'll
> probably opt for one of the pulse width modulated ones (those are
> much more complicated than the piper pass transistor, but they also
> dissipate very little power).

The next step in the evolution is to get rid of all those incandescant
bulbs and replace them with LEDs. Lower power consumption for the same
light output, and they never burn out.

>
>Oh no! Someone having the audacity to disagree with King Weir!
>That'll make him spit out his morning latte! Stand by for the flames.
>
>Good points John, and I agree wholeheartedly, but can you expect every
>A&P to fully understand each and every detail? I don't care to pay
>for an A&P's education, but it's almost like saying that you obtained
>your 30 years in a few months.
>

Well, I'm truly not looking for a flame war, and I really meant that little
blurb about a "confirmed lingerer"....just couldn't help myself.

It seems that in a discussion group like this there are always very vocal folks
that are always willing to tell you that their way is the better way and that
would have you believe that all mechanics and IA's are crooks or incompetent.

I find it very dangerous that there are folks out there in internet land that
spend their time spouting ways to decieve the FAA and get around the regs,
rather than trying to help folks work within the regs.

Just to clarify a few things, I believe that a good mechanic armed with a
multi-meter and schematic of the Piper instrument light system could do the
same. It does seem, however that many of my brothers and sisters in the biz
just don't have a good grasp on electricity in general and transistors in
particular.

Additionally, in my shop, if I happen to assign a green mechanic to a job such
as this and it takes him/her 5 or 6 hours to trouble shoot and repair.....I
WILL NOT bill the customer this amount. I will bill what I believe is an
adequate and fair amount. The up-side to this is that my mechanic will now be
"trained" and next time around, I won't lose my shirt on the deal. I think
what I was trying to say was that the $429 dimmer was a bit out of line, then
Mr. Weir piped in with his "better way of doing things" which is a tremendous
idea for a home built, but has no place in a certificated ship.

I actually do this on a regular basis. I will assign a green mechanic to a job
like this and with a few well placed nudges and a watchful eye, encourage
him/her to get a copy of the schematic and go troubleshoot. When the job is
done, the customer gets a bill based on what I think it would have taken ME to
fix the problem.

Interestingly enough, there have been times that I've cut a labor bill by
better than 50 percent and still caught hell from a customer. Go figure. (all
you accountants out there must understand that cutting a labor bill by 50% puts
me in the hole, figuring salarys, overhead, etc. etc). I just find it
interesting that nobody complains about the auto dealerships that flat rate
maintenance labor. You know, the guys that fix cars at the local Ford (insert
favorite car type here) dealership take home more pay than my mechanics. They
get about the same hourly rate, but a fair auto mechanic can turn in 60 to 80
hours in a 40 hour work week.....is that fair? Those hours are paid for by
YOU....the consumer.

What makes me so mad about this is the fact that these guys have almost no
liability......I could lose my home, my car, my job and every other thing I own
if a court/jury even THOUGHT I was neglegent......and guess what, jurys don't
make decisions based on regulations. Been there, done that.

We don't flat rate and I think I'd get out of the biz if we did.

The bottom line is....if you feel you're being taken by your mechanic, take
your maintenance dollar somewhere else. Just remember however that a
mechanic/IA that dosen't do his/her job exactly with the regs, isn't doing an
adequate job for you.....You as the PIC (per the regs) have the final
responsibility for the airworthiness of the aircraft you fly. My job as your
mechanic/IA is to keep your aircraft airworthy mechanically as well as
paperwork wise....and I am OBLIGATED under the regs to do both.

I really do understand though, that there must be some give and take, because
if I can't generate a pool of satisified customers, my shop will cease to
exist.

Phew....thanks for this opportunity to vent.......back to lurk mode for me.

> The bottom line is....if you feel you're being taken by your mechanic,
take
> your maintenance dollar somewhere else.

Thanks for the input, John. (You really *do* need to de-lurk here more
often.... ;-)

I have taken my business elsewhere in the past, when I truly felt I was
being ripped off. However, my current mechanic is an incredible guy, has
taken us out on his boat, has welded things for me, gratis, has helped me
bead-blast P-51 parts for our Mustang Suite, gratis. The list of favors
goes on an on.

He works ten times faster than the "corporate" shop on the field, although
perhaps not in this isolated case.

I will stick with him through one bad experience.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

I've been answering this same exact question for thirty-three years exactly the
same way, and I'm not going to go into the song and dance here again. You can
google the answer if you like, or you can download Applications Note 1 (the one
I wrote back in 1972 as amended through last year) from www.rstengineering.com
if you want the long answer.

Or, I can reproduce it here if you all would like some flame bait.

Jim


"Dan Thompson" >
shared these priceless pearls of wisdom:

->Wouldn't replacing an approved dimmer assembly with a home-made one be a
->"major alteration" that would require a Form 337, and field approval of the
->data, for return to service?



Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

Any body that understands
->that tranistorized dimming system (and its just not that complicated) SHOULD
->KNOW to verify that the light chain is not shorted before sticking in a new
->transistor. A short is about the only thing I've ever seen that will kill the
->otherwise beefy 2N3055 transistor.

And any engineer that designs a dimming circuit without short circuit protection
of the output device should be staked out with ants and honey.



->
->And to Mr. Weir......the 337 is for Major repair and Major ALTERATIONS.

And reasonable men interpret MAJOR differently. I have my sources that I've
published with a Chief Counsel's opinion. They are yours to google as you see
fit.



As
->the chief inspector for a large repair station, if I see an aircraft for an
->annual with some kind of aftermarket or home made dimmer system....it better
->have a 337 associated with it....not because I'm a jerk or an a**hole, but
->because that is what the regulations require.

And again, I beg to differ with your interpretation, as does the Chief Counsel.


Unfortunately, if I ignore that
->or miss that and the owner rolls the aircraft into a ball, even if it had
->nothing to do with the accident, I could be in big trouble with the feds or
->possibly be sued by the estate and loose every thing I've worked so hard for
->these last 30 plus years.

Them's the breaks, ain't they? Both of us have our respective hineys on the
line.


I've been the biz long enough

As have I, and we can disagree without being disagreeable.



"You seek your god in rule books and idols made by men, and all the while that
god is within you. Safety is that which you know, not what somebody else thinks
it would be nice for you to comply with. Ask your FAA inspector for the
approved definition of safety. There is none. How can any agency guide toward
that which it can't even define?" (Richard Bach, "Found At Pharisee")

Jim



Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

Had a double helping of bitch flakes this morning, did we Stu?

Jim


Stu Gotts >
shared these priceless pearls of wisdom:

->Oh no! Someone having the audacity to disagree with King Weir!
->That'll make him spit out his morning latte! Stand by for the flames.


Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

Three words...

Newly graduated engineer.



I wonder why
->Piper made it so complex later on,



Jim



Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

Actually, they are a little simpler to design than the old analog beasts, in
that you don't have to do a lot of thermal worst-case analysis. And, the
current limiting is a hell of a lot easier to do.

Watch out, though, that the person who designed it understands RFI and how close
to the noise margin the Loran is. You'd be surprised how many designs have
their switching frequency a submultiple of 100 kHz. and wonder why the loran
(and everything else harmonically related) goes Tango Uniform when the lights
come to life.

Also, you need to understand that switching frequencies on the order of 30 Hz,
90 Hz., 150 Hz., and 9960 Hz. will honk up the avionics also. The hell of it is
that radio manufacturers do a great job of shielding their product against this
sort of RFI, but then run a wire from the dimmer port directly to the lights,
letting any crap on the dimmer wire merrily radiate throughout the radio.

Jim

When my dimmer does
->go, or I add more lighting to the panel, I'll probably opt for one of the
pulse
->width modulated ones (those are much more complicated than the piper pass
->transistor, but they also dissipate very little power).



Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

> The next step in the evolution is to get rid of all those incandescant
> bulbs and replace them with LEDs. Lower power consumption for the same
> light output, and they never burn out.

Has anyone got an STC for this kind of set-up yet?
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

A friend of mine did their Stinson 108 with LEDs with appropriate Canadian
paperwork and it works incredibly well. As soon as I get my ac in May
it will be one of the first mods I get done to it. Easy to read, easy on the
eyes
and very cost effective.

Brendan


"Jay Honeck" > wrote in message
news:iQJ4c.6688$1p.158527@attbi_s54...
> > The next step in the evolution is to get rid of all those incandescant
> > bulbs and replace them with LEDs. Lower power consumption for the same
> > light output, and they never burn out.
>
> Has anyone got an STC for this kind of set-up yet?
> --
> Jay Honeck
> Iowa City, IA
> Pathfinder N56993
> www.AlexisParkInn.com
> "Your Aviation Destination"
>
>

Ray Andraka wrote:
>
> Err, that transistor is there so that the rheostat doesn't double as a space
> heater. It is there for a very good reason, although today there are better
> ways to dim rather than a pass transistor. For that price, you could have
> installed one of the pulse width modulated dimmers and done away with the old
> fashioned piper circuit. Would have required a 337, but then it would be the
> last time you'd ever have to deal with it. You might have even been able to
> get separate dimmer circuits for instrument and overhead lights out of the
> deal.

Be a bit carefull with PWM dimmers., if they get placed near the avionics
you might have problems with RFI .

Have a look at the circuitry for the alternator-fail annunciator
on the Piper Arrow. It wastes 4 watts just to keep a globe off.
(I'd always wondered why the comm-panel switches were always hot)

Jay Honeck > wrote:
> Personally, I think the dimmer circuitry in the Cherokee is perhaps the
> dumbest thing I've seen in aviation. Even I, as a total neophyte, can see
> that the system is hopelessly obtuse.

Ray has explained to you, twice in this thread, why transistors are used.
If you can't understand the technology, stop commenting on it.

--- Jay


--

__!__
Jay and Teresa Masino ___(_)___
http://www2.ari.net/jmasino ! ! !
http://www.oceancityairport.com
http://www.oc-adolfos.com

Roy Smith wrote:
>
> Ray Andraka > wrote:
>
> > When my dimmer does go, or I add more lighting to the panel, I'll
> > probably opt for one of the pulse width modulated ones (those are
> > much more complicated than the piper pass transistor, but they also
> > dissipate very little power).
>
> The next step in the evolution is to get rid of all those incandescant
> bulbs and replace them with LEDs. Lower power consumption for the same
> light output, and they never burn out.

Yep.., I've made my own GE330 replacements for the annuniciator and
gear-down lights using white LEDs.
I believe there are commercially avialable units but be carefull
because incandescent lamps are non-polarised but the polarity of the
lamp sockets is random. (My Arrow requires a + base for the gear lamps
but a - base for the annunciators)

->And any engineer that designs a dimming circuit without short circuit
protection
of the output device should be staked out with ants and honey.

Yes, I agree, however it wasn't designed with output protection and anybody
that works on it shoud understand that

-> I have my sources that I've
published with a Chief Counsel's opinion.

A chief counsel doesn't survail those of us out in the field.


As
->the chief inspector for a large repair station, if I see an aircraft for an
->annual with some kind of aftermarket or home made dimmer system....it better
->have a 337 associated with it....not because I'm a jerk or an a**hole, but
->because that is what the regulations require.
->And again, I beg to differ with your interpretation, as does the Chief
Counsel.

I beg to differ with you and your chief counsel's opinion, if its not as it
came from the factory then it does not conform to its type design and needs a
vehicle of approval, what-ever that may be. I'll be glad to argue that point
to you or counsel (as long as we can avoid the flaming)


-> Them's the breaks, ain't they?

Yup, its a heck of a biz....gotta love it or it'll kill ya....figuratively


-> Ask your FAA inspector for the
approved definition of safety. There is none. How can any agency guide toward
that which it can't even define?"

Jim, of all the stuff of your's I've read, I must say that is a great line.....
Lets not however, miss the forest for the trees. Some legal eagle in a nice
air conditioned office hasn't a clue about what really happens out here on the
front lines of the maintenance battlefield. Those of us with grease under our
finger nails don't deal with a Chief Counsel, we deal with Aviation Safety
Inspectors that may or may not know as much as we do. Truth be told, I really
enjoy "playing ball" with the FAA, but, ya know.....if I make 'em mad enough,
they'll take the ball and bat and go home....if you know what I mean.

By the way, I'd enjoy arguing regulations with you....as chief inspector for a
repair station, that's what I do for a living. Unfortunately, my responses may
be a little delayed if it involves quoting regs. I surf news groups from home
and all my reg stuff is at work.

I've proven the Feds wrong a few times, but eaten a lot of crow along the way!


By the way Jim, didn't I read in one of your posts that you were a Ham?? Be
glad to try a sked on HF and we can really get into a spirited discussion.....I
can work 160 up to 10 with 100 watts to a dipole oriented east to west.

best 73 John

> Ray has explained to you, twice in this thread, why transistors are used.
> If you can't understand the technology, stop commenting on it.

Wow, we normally can't find anyone here to defend the high-tech 1974 Chevy
Nova technology found in my Piper -- thanks!

Your view is, um, refreshing, somehow. Kinda like the Amish, I suppose, but
I guess I could get used to it.

Actually, flying a 30 year old airplane, I have little choice. :-(
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

: Personally, I think the dimmer circuitry in the Cherokee is perhaps the
: dumbest thing I've seen in aviation. Even I, as a total neophyte, can see
: that the system is hopelessly obtuse.

: Strangely, older Cherokees had a much simpler dimmer circuit. I wonder why
: Piper made it so complex later on, and I wonder if they've corrected this
: mess in their new planes?

I won't debate the older vs. newer circuit too much, except to say that it
moves the heat loss from a rheostat to a transistor. Both are linear "regulators",
but due to the changing load requirements a resistor makes a very poor choice. My
plane's the older variety, and the lights are off for about 75% of the travel of the
dimmer. The other 25% goes from off to full bright, and makes the last 25% of the
rheostat coils have to dissipate all the power.

They're both a bit clunky (PWM being more efficient, but prone to noise as
previously mentioned). Aside from this being an AIRPLANE, the transistor setup is
CHEAPER and "better" from the linearity and robustness standpoint (TO-3 package 2N3055
is a tough transistor that can dissipate a lot of power). In reality, the 20W or so
max is negligible power lost (1-2A draw) and a decent compromise for complexity
and noise immunity. Still better are LEDs... less power, and even a linear regulator
won't have to dissipate much.

Hope that helps describe why they went to it.

-Cory



--
************************************************** ***********************
* The prime directive of Linux: *
* - learn what you don't know, *
* - teach what you do. *
* (Just my 20 USm$) *
************************************************** ***********************

> Hope that helps describe why they went to it.

Thanks, Cory!

Do you know if there's a legal way to put LEDs in my plane?
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

"Jay Honeck" > wrote in message news:<rkp4c.18266$mM.131800@attbi_s02>...
> And it's not even for the Dept. of Defense! :-)
>
> For those of you thinking about airplane ownership (and I know you're
> lurking out there!), we just got the bill to replace one of the two dimmer
> switches (and a few light bulbs) in our Pathfinder's panel.
>
> $104 in parts, 5 hours labor (It's a real bitch to diagnose and get at in a
> Cherokee...).
>
> Total: $429.73.
>
> Gotta love aviation.

That is why alot of us are building experimental planes. I have owned
several certified ships and "Never" again will I get
screwed......Happy Flying.

Ben Haas N801BH

On Sat, 13 Mar 2004 08:10:48 -0800, Jim Weir > wrote:

>
>Had a double helping of bitch flakes this morning, did we Stu?
>
>Jim
>
Man, I just couldn't resist!


>
>Stu Gotts >
>shared these priceless pearls of wisdom:
>
>->Oh no! Someone having the audacity to disagree with King Weir!
>->That'll make him spit out his morning latte! Stand by for the flames.
>
>
>Jim Weir (A&P/IA, CFI, & other good alphabet soup)
>VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
>http://www.rst-engr.com

On 13 Mar 2004 22:26:18 GMT, (JohnN3TWN)
wrote:

snip

>By the way, I'd enjoy arguing regulations with you....as chief inspector for a
>repair station, that's what I do for a living. Unfortunately, my responses may
>be a little delayed if it involves quoting regs. I surf news groups from home
>and all my reg stuff is at work.

http://www.access.gpo.gov/nara/cfr/waisidx_04/14cfrv1_04.html

enjoy

TC

And please to add:

http://www.awp.faa.gov/new/fsdo/ans_jan2_98.htm

http://www.awp.faa.gov/new/fsdo/ans_july1_97.htm

http://www.awp.faa.gov/new/fsdo/ans_apr3_99.htm

Jim


shared these priceless pearls of wisdom:

->On 13 Mar 2004 22:26:18 GMT, (JohnN3TWN)
->wrote:
->
->snip
->
->>By the way, I'd enjoy arguing regulations with you....as chief inspector for
a
->>repair station, that's what I do for a living. Unfortunately, my responses
may
->>be a little delayed if it involves quoting regs. I surf news groups from
home
->>and all my reg stuff is at work.
->
->http://www.access.gpo.gov/nara/cfr/waisidx_04/14cfrv1_04.html
->
->enjoy
->
->TC



Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

Jay Honeck > wrote:
:> Hope that helps describe why they went to it.

: Thanks, Cory!

: Do you know if there's a legal way to put LEDs in my plane?
: --
: Jay Honeck
: Iowa City, IA
: Pathfinder N56993
: www.AlexisParkInn.com
: "Your Aviation Destination"

I believe there's a company that make little plastic ring doodads to go around
the instruments. Not cheap, though. The trouble with LED's is that they don't work
the same as light bulbs. They're a current-controlled device, and a bulb is roughly a
voltage^2-controlled device. If you have some of each, it'd be tough to get them to
dim at the same "rate." As far as getting stuff approved, depends on your friendly
neighborhood FSDO, I guess. You just fixed yours... leave well-enough alone! :)

Wait a minute... didn't you taunt the airplane gods a week or two ago about
how *everything* on your plane worked? :P~~

-Cory



--
************************************************** ***********************
* The prime directive of Linux: *
* - learn what you don't know, *
* - teach what you do. *
* (Just my 20 USm$) *
************************************************** ***********************

> Wait a minute... didn't you taunt the airplane gods a week or two
ago about
> how *everything* on your plane worked? :P~~

Yep. This repair was part of the procedure that got everything to work -- I
only just received the bill for it, now.

At the moment, everything STILL works!

:-)

(Of course, it's too damned windy around here to fly -- again. Windiest
March I've ever seen...)
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

OK, I did what you said. I read your App. Note 1. Also googled around for
other things you have written. I guess I still don't "get it."

Your App. Note 1 references an AC that was superseded back in 1996, AC
20-62C, which is now AC 20-62D. The current version says in the definition
of "Acceptable Parts": "(2) Parts produced by an owner or operator for
maintaining or altering their own product and which are shown to conform to
FAA-approved data." So how can an owner's home-made dimmer circuit can be
installed without any approved data?

You have cited the "Chief Counsel" on several occasions. Do you mean, by
any chance, the "Assistant Chief Counsel for Regulation letter dated Aug. 5,
1993 " referred to in http://www.awp.faa.gov/new/fsdo/ans_jan2_98.htm? I
would like to see that letter, if you know anywhere that it is published.
Unless it is publicly available, it would be hard for someone to cite it as
an authority.



"Jim Weir" > wrote in message
...
>
> I've been answering this same exact question for thirty-three years
exactly the
> same way, and I'm not going to go into the song and dance here again. You
can
> google the answer if you like, or you can download Applications Note 1
(the one
> I wrote back in 1972 as amended through last year) from
www.rstengineering.com
> if you want the long answer.
>
> Or, I can reproduce it here if you all would like some flame bait.
>
> Jim
>
>
> "Dan Thompson" >
> shared these priceless pearls of wisdom:
>
> ->Wouldn't replacing an approved dimmer assembly with a home-made one be a
> ->"major alteration" that would require a Form 337, and field approval of
the
> ->data, for return to service?
>
>
>
> Jim Weir (A&P/IA, CFI, & other good alphabet soup)
> VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
> http://www.rst-engr.com

Jay Honeck > wrote:
>> Ray has explained to you, twice in this thread, why transistors are used.
>> If you can't understand the technology, stop commenting on it.
> Wow, we normally can't find anyone here to defend the high-tech 1974 Chevy
> Nova technology found in my Piper -- thanks!

Using that logic, we'd might as well disconnect our yokes, and roll a
brand new plane underneath them. It's not practical to redesign
everything on our planes, just because you don't like the way they did it
in 1974 (or '64 or '54).

> Your view is, um, refreshing, somehow. Kinda like the Amish, I suppose, but
> I guess I could get used to it.

My engineering degree trumps your silly little english degree when it
comes to commenting on technology.

> Actually, flying a 30 year old airplane, I have little choice. :-(

Exactly, now your gettting it.


--

__!__
Jay and Teresa Masino ___(_)___
http://www2.ari.net/jmasino ! ! !
http://www.oceancityairport.com
http://www.oc-adolfos.com

> My engineering degree trumps your silly little english degree when it
> comes to commenting on technology.

My Dad -- a high school grad -- used to have a word for all the engineers in
his department.

He called them "employees."

;-)
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

"Gene Kearns" > wrote in
:

>>broke within 1 hour because the mechanic (1) couldn't solder and (2)
>>had no notion of how to properly suppport soldered wires against
>>vibration.
>
> Not to mention prohibition against soldering (unless absolutely
> unavoidable) that most A&Ps have been taught.

Unfortunately, you are right. Lots of A&P's (and IA's) work more off of
old wives tales like this than facts.

Studies have found that *correctly* formed connections, both crimp and
soldered, have virtually identical (and low) failure rates in aviation use.
Only the mode changes - crimps fail from corrosion or pull, *sometimes*
from breakage at the connector. Soldered connections, improperly done,
fail from breakage at the connector and from cold solder joints.

The only real advantage to crimp connectors is that it is a little easier
to *automate* the job, and hence they may be better in the hands of someone
without training. Otherwise, both have their proper place.

-----------------------------------------------
James M. Knox
TriSoft ph 512-385-0316
1109-A Shady Lane fax 512-366-4331
Austin, Tx 78721
-----------------------------------------------

"James M. Knox" wrote:
>
> Unfortunately, you are right. Lots of A&P's (and IA's) work more off of
> old wives tales like this than facts.

No, A&Ps work with the methods and procedures defined in AC.43. The "bible" says
no soldering unless absolutely necessary.

George Patterson
Battle, n; A method of untying with the teeth a political knot that would
not yield to the tongue.

Ya know, this has all been great fun, but a huge time sink. I'll take the
thread up again next weekend, but I won't waste valuable engineering time with
folks who have an honest difference of opinion. Opinion, mine as well as yours,
are like assholes...everybody has one and most of them stink.

See ya after hours...

Jim
Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

G.R. Patterson III > wrote:
: No, A&Ps work with the methods and procedures defined in AC.43. The "bible" says
: no soldering unless absolutely necessary.

While this is not an unreasonable limitation, it is not possible to attatch
wires to a potentiometer without soldering (the initial problem that the
A&P mechanic was to fix), so I had (erroneously) assumed that this mechanic
was knowledgeable about the proper practices of soldering and wire support in
high-vibration environments. Sadly I was mistaken, but the ruins of the
installation were recoverable with proper soldering technique and wire
dressing.

Perhaps we are (I am) expecting too much of one man. This particular mechanic
is extremely knowledgeable about structures and most powerplane issues. He's
less knowledgeable about electrical problems, and not at all comfortable with
electronic items - I helped him diagnose some bad engine monitor probes (not
in my plane). If he had told me "I do not think that I can perform this
repair" I would have been perfectly happy, and would have gone elsewhere.
--
Aaron Coolidge (N9376J)

>Not to mention prohibition against soldering (unless absolutely
>unavoidable) that most A&Ps have been taught.
>

I was never prohibited from soldering and spent hours doing it. Granted this
was 20 years ago.

One thing about these aircraft dimmer switches is that there is typically very
little service loop in the wire bundle so very often you have to lie on your
back and solder upside down. I have also seen installations where it could
take nearly an hour just to expose the switch for soldering and more to put it
back together correctly.

It always amazes me how often things were designed without any thought to
future maintenance requirements.

John Dupre'

In article >,
(JDupre5762) wrote:

> It always amazes me how often things were designed without any thought to
> future maintenance requirements.

I suspect your typical 30-40 year old piston single was designed mostly
to meet a sales price point. I also supect if you told the guys in the
factory who built the 1968 Arrow I fly that this plane would still by
flying 35 years later, they would have thought you were nuts.

"Roy Smith" > wrote in message
...
> In article >,
> (JDupre5762) wrote:
>
> > It always amazes me how often things were designed without any thought
to
> > future maintenance requirements.
>
> I suspect your typical 30-40 year old piston single was designed mostly
> to meet a sales price point. I also supect if you told the guys in the
> factory who built the 1968 Arrow I fly that this plane would still by
> flying 35 years later, they would have thought you were nuts.

Most things are made for and sold at a price point otherwise there would be
no such thing as different models.

The kettle I bought yesterday for $19.99 was made for a pricepoint as was
the $9.99 kettle.

The same for aeroplanes

I don't have an opinion. I just want to learn. Come back and cast some
more pearls ....

Meanwhile, I did find out a couple more semi-official FAA opinions:

http://www.faa.gov/avr/afs/news/archive/Jul_Aug2002/Parts.htm

http://150cessna.tripod.com/obrienonownermadeparts.html

Again, the gist seems to be that owner made parts have to be based on
approved data of some kind. The owner can't just roll his own, no matter
how much better it is, without a field approval.

"Jim Weir" > wrote in message
...
> Ya know, this has all been great fun, but a huge time sink. I'll take the
> thread up again next weekend, but I won't waste valuable engineering time
with
> folks who have an honest difference of opinion. Opinion, mine as well as
yours,
> are like assholes...everybody has one and most of them stink.
>
> See ya after hours...
>
> Jim
> Jim Weir (A&P/IA, CFI, & other good alphabet soup)
> VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
> http://www.rst-engr.com

(JDupre5762) wrote in
:

>>Not to mention prohibition against soldering (unless absolutely
>>unavoidable) that most A&Ps have been taught.
>>
>
> I was never prohibited from soldering and spent hours doing it.
> Granted this was 20 years ago.

There is still no prohibition against it. I went through the
"maintenance procedures" manual last night, and soldering certainly gets
short shift... but nothing prohibits it. Reading more recent articles,
soldering appears about as common as crimping (not saying it is done as
often, but rather that the two are simply considered both standard
methods for making electrical connections).

Crimping is still favored because, with the right tool, almost any moron
can do a good crimp. Soldering is like crimping without an automatic
tool - can be done just fine, but requires someone who knows what they
are doing. [But isn't that what we wish regardless?]

The key is good quality workmanship on the connection, with adequate
strain relief and anti-vibration bundling as necessary. Done right, ANY
good connection should last a lifetime.

-----------------------------------------------
James M. Knox
TriSoft ph 512-385-0316
1109-A Shady Lane fax 512-366-4331
Austin, Tx 78721
-----------------------------------------------

>Again, the gist seems to be that owner made parts have to be based on
>approved data of some kind. The owner can't just roll his own, no matter
>how much better it is, without a field approval.
>

Yup...there is the key. And by regs, the installing mechanic is responsible
for assuring this to be so.

And Jim, I'll be back this weekend when I have more time.....with my "smelly"
opinion