[TowerTalk] yaesu rotor controller repair

[Kevin Normoyle]

since we're talking yaesu, I'll throw something out in case someone can help. 
I'm shotgunning this debug, but maybe someone has experience that can help.

I have a g-1000dxa controller that had two problems: the preset didn't work, and 
when a rotation of 450 deg. at the rotator only indicated 360 deg of rotation at 
the controller, no matter how i adjusted things.

I have two g-1000dxa, so I was able to compare with known good 
rotator/controller combinations, so I knew the problem was localized to the 
controller.

The other problem was that I couldn't adjust the output voltage to the rotator 
to be more than 20v. The known good one can be adjusted to 28v with 24v typical.

So I couldn't really figure out the operation from the schematic. The controller 
board is not available separately from Yaesu, only it + PSU board for $300. So 
that didn't make sense since digital controller replacements are available for $250.

So looking at all the parts on the bottom of the control board (it's easy to 
take out..double sided..most active parts on the bottom, so can't see unless you 
remove)....it seemed like the most likely suspects were the op amps.

They were available cheap (<$1 each) so I replaced the two quad op-amps (TSOP 
packages..not bad though if you have a fine tipped low wattage iron) and the 
preset worked, but still the 360 vs 450 degree issue. Replaced the two dual 
op-amps and now the indicator goes 450 like it should. The part #s on the 
schematic (and manufacturer) were available online.

But I still only get 20v output, so that issue bugs me. Although this is on a 
lighter antenna array, so it actually turns fine.
I do get some reduction in voltage with the speed adjust and the on-board pot 
adjust, but not like on the known good controller

  I did notice that a series resistor in the output from the controller board 
(from an op amp) seemed to have changed value..I changed that but didn't notice 
any difference.

I'm thinking there might be an issue with some of the transistors on the PSU 
board, but those part numbers aren't immediately available online. (maybe I can 
look harder)

This was all probably due to static or lightning. Although it's possible the 20v 
issue may be due to driving an overloaded antenna array? Wonder if some 
transistor might have gotten cooked.

any thoughts or experiences repairing the electronics on a yaesu controller?

-kevin
ad6z