PD50G1 -Vy Testing Positive Voltage

[ChrisV]

Troubleshooting a plasma with no picture. Looking at the YSUS, the -Vy target is -195. My actual is +195v with only the bottom buffer board attached. There is no voltage on VA or VSC with upper buffer board in place.
I'm thinking, I have a bad upper buffer board. What would cause the -Vy to test positive?
Thanks for any help that is offered

[tom66]

Re: PD50G1 -Vy Testing Positive Voltage

Such a positive -Vy would certainly be explosive to any capacitors nearby, so I doubt it's the case. Just need to reverse probes.

[ChrisV]

Re: PD50G1 -Vy Testing Positive Voltage

Thank you for the reply Tom66.
Just for clarification, if I check voltage in the way that is described in the photo above, with red probe on + and black probe on -, it is a positive voltage. If I reverse the probes and place the red on the - and the black on the + it has the correct negative voltage.
Could there be something wrong with my DMM or would this indicate correct voltage at this test point?
Thanks again.
PS - Thanks for making the service manuals available

[tom66]

Re: PD50G1 -Vy Testing Positive Voltage

I think it's a mistake in the service manual. Nothing to worry about.

[ChrisV]

Re: PD50G1 -Vy Testing Positive Voltage

Thank you Tom