(tuno) wrote in message . com...
The B40 that came with my glider has this curious fault: after
experiencing an updraft of 10 knots or greater, the rapid,
high-pitched (i.e. "saturated") audio tone gets "stuck" and continues
indicating 10+ knots until the B40 registers a negative value (sink).
Has anyone else encountered this problem or know if there's a fix?

-ted

Ted I am a Borgelt Dealer in the US, and asked Mike Borgelt about
your problem.

Richard Pfiffner
Craggy Aero
www.craggyaero.com

The pointer and the audio are driven by the same signal. Every B40
gets tested for full range of the audio and I've never seen this
problem in nearly 900 B40's, however examination of the circuit
diagram indicates to me that I think there is a problem with the
LMC660 quad op amp on the audio board. One of the four amps level
shifts and inverts the meter signal so as to drive the audio generator
and this is the only place something like this could occur. I suggest
the LMC 660 be replaced and I'm pretty sure the problem will go away.

We can fix this or any competent avionics tech should be able to
perform this fix.

Regards

Mike
Borgelt Instruments - manufacturers of quality soaring instruments
phone Int'l + 61 746 355784
fax Int'l + 61 746 358796
cellphone Int'l + 61 428 355784
Int'l + 61 429 355784
email:
website: www.borgeltinstruments.com