What there is of a service manual is at :

http://exodus.poly.edu/~kurt/manuals...%20Service.pdf

I do believe an actual schematic would help. I need the vertical deflection circuit.

OK, I blew out the power supply by making a short with the probe at the input to the -12 volt regulator. Of course it has an obscure HP part number on it but I can see it is a simple 7912 regulator. It is possible I blew it shorting the input if it has alot of capacitance on the output but that is not really an issue right now. First I will get the power supply up again. The referenced URL there has some basic block diagrams, and I am pretty sure I just blew a fusible somewhere.

But the reason I was in there in the first place is because it has a fault in the vertical sweep - foldover. Like on a TV when the boost cap or circuit fails, EXCEPT on this baby it is at the bottom of the raster as it does not scan top to bottom, but bottom to top.

It is not easy to follow this circuit because of the two sided board, but not impossible. The problem is that those people could put anything anywhere, and do. I can tell the vertical output is common emitter complementary push pull. The collectors are hooked together and are the output high side.

I do not see a third "retrace" transistor anywhere, but knowing how engineers are it might be on the frikken control panel or something. Also, retrace boosters are hard to implement with a common emitter push pull circuit.

I actually cannot see the yoke, but observing the high side of the vertical output I know it has one because it looks pretty much like the yoke drive in a TV. If electrostatic it would just be a sawtooth wave.

I would really like to see a detailed schematic of the vertical circuit here. I do not just "try" parts to see if that was the fault usually and I am certainly not going to start on something like this. I know that in instrumentation I cannot get away with some of the **** you can flub in a TV set or a stereo. I learned the hard way that when they say 15 volts they do not mean 16.5 is OK, it usually is not.

The thing puts out the waveform incoming along with the spectral analysis at the top. A sine wave was showing what looks like severe crossover distortion in an audio amp, but another scope confirmed it was not like that. Looked a little closer and the raster is not filling the screen and there is a compression right there. I also think I am missing one of the function names. They are on screen next to the buttons and none of that lines up of course.

Anyway, I am seeing hints of a "Volume 2" of the service manual which I suspect contains the information I want. I have been almost everywhere and it is not to be found. If anyone has it I need it, even if you have it on paper and could scan me a JPG of the vertical circuit would be fine. (if you can't get my email from this post I will give it to you, unless you can Dropbox it or something)

Really, I can probably do it without but it would take a hell of alot more time.

Thanks in advance for anything helpful.