[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

G5400 rotator problem followup

A few months ago, I mentioned a problem that I was having with the Yaesu
G-5400 rotator control box. I had mentioned that it appeared to no longer
provide an output of up to 5 volts to allow full calibration under WISP.

I finally figured out the problem and it was a bit more obscure than you would
expect. Therefore, I'll share my findings with the group. I had checked
including the op amps and diodes. The problem appeared to be both elevation
and azimuth, but all the components appeared good. My assumption was that
this problem occurred after a close lightning strike, but I had not used
the unit
for some time so could not be sure.

Finally, I decided to check the voltage output adjust potentiometers and found
that they had both fried near the end stop thereby giving a high resistance
at the final adjustments. This is also the reason why the outputs were not the
same for both azimuth and elevation. It is also the reason why the idicator
meter displays were not affected since they have their own adjustments.

It appears that a near lightning strike did affect the unit. The output
adjustments do not have a series resistor in the output leg where by the
metering potentiometers do. Never thought to check them first since they
were adjusting the output voltages, just not sufficiently to give the 5 volts.

Hope this is helpful to someone else.

Reid Bristor,  WA4UPD
Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org