I put a power supply in from another 'scope. It starts right away.1. The problem is definitely in the power supply.
The power supply runs out of the 'scope with a load per the manual.
Installed in the 'scope and running on an isolation transformer so I can attach anothe 'scope:
I shorted the current sense resistor and put a 'scope on the collector of Q1040. The?PS does?not start. No sign of Q1040 turning on.I put an analog meter on the current sense resistor. The voltage is steady at 103 mV (515 mA).2. It is not overcurrent preventing starting.
Heat blown into slots in the top cover does speed up recovery. It does not take much and I don't really know what I'm heating. Something center or more to the front I think.
When running the AC current flickers at 1.1 amps and seems to want to drop to 1 amp. I have seen it running at 1 amp with jumps to 1.1 amps.
My other 2465 runs steady at 0.95 amps. It?has one less option board.
There is?something surging power. If the current surges were caused by any of the regulators after T1060 it would show in the current limit sensing.
Same goes for anything in the Q1060 and Q1070 drivers. It only leaves the Q1062 circuit or the voltage doubler input. I did not change the voltage doubler capacitors.
Any suggestions? Remember I have to disconnect 18 cables, remove the top cover with the CTS and GPIB option boards, and remove the power supply for every test.
All aluminum electrolytic capacitors except the doubler pair have been replaced. CR1022 and Q1040 have been replaced, so has C1024.
Q1050, Q1060, and Q1070 would show up in the current sense if they were the cause.
