2465B what should the Inverter voltage be with a primary test load be?


The triangle ripple seems very high at 15-20V, check the ESR and capacitance of the bus caps on the PRI REG,

Usually the ripple of a switcher should be ~ 1-2% of the DC, not 10%.



Hi John,

I know this an old thread, but I'm in the process of repairing a PS as well.

I got the same: a rock solid 120.4V ,but with a ( bit distorted) 15-20V triangle riding on top.

After reading your message, I assume there is a typo in the service manual flowchart.

Stay safe,



Can any one tell me what voltage you have seen with the "primary test load"?

I have been working on a 2465B that had a burned smell on power on.

(message 87960 and 87620)

I think the primary problem was that the -8V cap C1102 leaked and the board under it turned conductive and fried. I have drilled a hole in that spot now.

Something else is not working

I removed the all the caps on the secondary side of T1060 except for the +5VD and I have two, Two ohm resistors connected for a +5v load.

The inverter runs with a low input voltage (less then 90VAC) but cuts out as the input voltage increases.

To try to track down the problem I made a Primary test load and connected it.

I get about a 120 VDC average across the test load but the voltage swing is more like +/- 10 V to 15 V with a triangle wave with the positive tips flattened.

The Inverter trouble shooting flow chats say that their should be 120V with a 1V P-P triangle wave.

The only thing I can see is that R1071 has been hot. Other then the larger triangle wave I don't yet see what the problem is.

Not making any progress I went to another working 2465B with power voltages that check ok and removed the power supply, I had to change the X2 line capacitors anyway.

I placed it in the original bad scope and it worked.

To compare with the non-working supply I took it back out on the bench and connected the primary test load and get the same looking wave which has a much higher P-P voltage then listed in the manual. 120V with about 20V peak triangle wave (smaller p-p as the load is increase by 75W but still at 10-15 volts p-p)

Can any one tell me what voltage you have seen with the primary test load?

Should it a 1-2V triangle or 20V triangle wave?

If it should be 1-2V what would make it higher?

John Snyder