Refurbishment only, I hope.
I bought this good looking vintage 792A puls gen for €10 as "powers on, untested" which I think could be a nice score? It does power on and seems to work, at least somewhat, but the dials and verniers are very noisy so it is a bit hard to tell yet. At one point I did get a steady pulse out of it at around 4.4MHz.
I can't find much on it so does anyone have a service manual or schematic? Does anyone know anything about this generator, specs and age would be interesting?
Front looks nice but BNC's are black. Mains connector on back does not look original but is nicely done.
Top side, tinned traces only.
Bottom side, nice and shiny gold plating I presume? I measured the thickness of traces to about 0.19mm, several times in different places - that is around 5.5oz copper plus gold, right?
The rotary switch contacts are oxidized and dirty and it looks a bit worse than the image below shows. I'm guessing that they are possibly fragile so how should I go about cleaning them? I have Kontakt Chemie Kontakt 60, 61 and WL but I don't like it flying everywhere and desoldering and taking them out feels a bit risky. The vernier pots are encapsulated in metal and without any good holes for thorough cleaning, I think, so I'm guessing I might have to take the switch/pot assembly out and disassemble anyway?
I have never seen components like the dotted red one or that black one, what are they? The color code makes me think that it could be a capacitor but the arrow, a polarized cap perhaps? The black one has three pins I believe, In, Out and Gnd.
And this, above the cap? Measured in circuit there is no continuity or capacitance but 1.715K Ohm across and in diodemode 1.0062V one way and 1.4585V the other way.
Rail voltages are written on the board so I measured them after warming up for half an hour. A bit high but nothing alarming, I think? Resistors in the supply that have drifted over the years?
Rail | Measured |
7.5V | 8.11V |
0-20V | 0-22.14V |
15V | 16.34V |
Help and suggestions on how to proceed are greatly appreciated.