Need 302 help

I have a Cambridge 302 that, until 4 weeks ago, was working fine.

Now, at power up, it seems to calibrate the needle just fine and then, after a few seconds, sends the needle sweeping around with a buzzing or clicking sound. It does this a few times and then settles down. Curiously, the circling graphic is illuminated after the needle calibrates.

In flight while thermalling, the 302 works great, both vario and averager, and agrees with the mechanical vario.

In level flight, it is possessed by a gremlin. The needle swings wildly and the audio follows. The speed to fly graphic is way off - indicating "slow down" even at very slow air speeds. However, the vario graphic seems to be reasonably in line with the mechanical instruments. Thus, the vario needle and sound seems to be independent of the graphical vario read out.

I've checked the settings, the polar, and the power supply. All seem to check out fine.

The 302 and 303 units were rebuilt at the factory by a prior owner in June 2012 so I believe I am dealing with a new problem.

Any advice would be greatly appreciated!

Lou

It makes no sense, but when mine started hanging up on initial power up, the
advice I got here was to check that the OAT probe was securely plugged in.
You might check that and the other connector.


"MNLou" wrote in message
...
I have a Cambridge 302 that, until 4 weeks ago, was working fine.

Now, at power up, it seems to calibrate the needle just fine and then, after
a few seconds, sends the needle sweeping around with a buzzing or clicking
sound. It does this a few times and then settles down. Curiously, the
circling graphic is illuminated after the needle calibrates.

In flight while thermalling, the 302 works great, both vario and averager,
and agrees with the mechanical vario.

In level flight, it is possessed by a gremlin. The needle swings wildly and
the audio follows. The speed to fly graphic is way off - indicating "slow
down" even at very slow air speeds. However, the vario graphic seems to be
reasonably in line with the mechanical instruments. Thus, the vario needle
and sound seems to be independent of the graphical vario read out.

I've checked the settings, the polar, and the power supply. All seem to
check out fine.

The 302 and 303 units were rebuilt at the factory by a prior owner in June
2012 so I believe I am dealing with a new problem.

Any advice would be greatly appreciated!

Lou

At 20:36 24 August 2013, Dan Marotta wrote:
Lou,
I believe there is a way to completely reboot a 302, it will also erase all
flight logs.

Hopefully someone can chime in on this procedure.

You might get some contact cleaner and a new toothbrush and clean all
connections, gps, temp probe etc.
With CAI out of business we 302 owners really need someone to service these
units. It would be awesome for someone to pick up this service business.



It makes no sense, but when mine started hanging up on initial power up,
the
advice I got here was to check that the OAT probe was securely plugged in.

You might check that and the other connector.


"MNLou" wrote in message
...
I have a Cambridge 302 that, until 4 weeks ago, was working fine.

Now, at power up, it seems to calibrate the needle just fine and then,
after
a few seconds, sends the needle sweeping around with a buzzing or clicking

sound. It does this a few times and then settles down. Curiously, the
circling graphic is illuminated after the needle calibrates.

In flight while thermalling, the 302 works great, both vario and averager,

and agrees with the mechanical vario.

In level flight, it is possessed by a gremlin. The needle swings wildly
and
the audio follows. The speed to fly graphic is way off - indicating "slow

down" even at very slow air speeds. However, the vario graphic seems to
be

reasonably in line with the mechanical instruments. Thus, the vario
needle

and sound seems to be independent of the graphical vario read out.

I've checked the settings, the polar, and the power supply. All seem to
check out fine.

The 302 and 303 units were rebuilt at the factory by a prior owner in June

2012 so I believe I am dealing with a new problem.

Any advice would be greatly appreciated!

Lou

I did some more research and found the following -

In screen # 10 (0)- In the first option - IAS - the glider was on the ground and not moving. The digital readout was 618 kts and seemed to be variable - stable for awhile and then changing both up and down. When the readout changed, the buzzing sound I am hearing at start up was present.

In the next screen option in Screen 10, ASI - Airspeed Indicator (ASI) zero offset, it was a fixed 3614 and showed the thermalling icon. The manual says this should be less than 1000.

All other options in Screen 10 seemed to be working fine.

The consensus at the field is that the unit needs repair. Might these clues trigger any ideas?

Dan - Thanks for the idea on the OAT. The Air Temperature probe connection is secure and both the instrument and outside temperatures in screen # 10 (0) seem to be reasonable.

Dogger - If I can't come up with a better answer, I may try the reboot option.

Thanks in advance for any help.

Lou




On Saturday, August 24, 2013 8:12:47 PM UTC-5, dogger wrote:
At 20:36 24 August 2013, Dan Marotta wrote:

Lou,

I believe there is a way to completely reboot a 302, it will also erase all

flight logs.



Hopefully someone can chime in on this procedure.



You might get some contact cleaner and a new toothbrush and clean all

connections, gps, temp probe etc.

With CAI out of business we 302 owners really need someone to service these

units. It would be awesome for someone to pick up this service business.







It makes no sense, but when mine started hanging up on initial power up,

the

advice I got here was to check that the OAT probe was securely plugged in.