$429 Dimmer Switch

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 !

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

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

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

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)

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...