Run each test with only 1 gen online, 50 to 100 amps load, try to hold conditions quite similar for each test.
some other thoughts:
look at big E terminal, small 20awg terminal.
double check each GCU voltage. Is it stable at 28.5? is it stable with load? is it stable with RPM change?
select cockpit red switch to off. Is the voltage of a running generator, cockpit switch selected off, .7v to 1.0v at idle? this checks the quality of the permanent magnets inside the Generator.
ASSURE that NO ENGINE GENERATOR has a cooling fan installed. (possibly a borescope through the black sooty outlet.) or it mat be necessary to unbolt the cooling exhaust.
#3 Gen Light occasionally, Much troubleshooting. Gen 3 amps tend toward zero. #1 seems to “take the load”
#3 gen troubleshooting, #1, #3 gen shunts…..?Removed?
Old Auxilec presentation:
The valve opens correctly with shop air applied, and the controller disconnected, and slight vacuum applied to control circuit
Front valve will open when control i connected straight to the pneumatic relay.
Ground prepress seems to work correctly
Aircraft pressurizes hard on the ground, straight to 3 psi at idle. Fwd valve will not open via the controller.
Turns out the limit valve was failed. It had opened because the pilots got the cabin to 17,000 feet. Then the brass seat fell out of place. Then valve leaked from then on .
Removed failed altitude limit valve PN 102466-1 SN 88-2322. Installed serviceable valve received on form. PN 102466-1 SN 17-1898
Removed failed anti-ice pressure reducing valve PN 38E59-1D SN 2907 -U. Installed Ovrrhauled valve recieved on AVITECH W.O. 1021932 PN 38E59-1D SN RF3502.
Move #1. . Rh ob spioleron, outborad end of the pushrod shorten 1 .5 turns.
Move #2 left speed brake panels loose. Lower two cable found at 16,17.= 30lbs.
.tighten 2nd to the bottom 1 turn, loossrn bottom 1 turn.