Trying to say here that there's an impedance matching terminator connecting the "far side" of the top plate and the "far side" of the bottom plate. Raymond

I'm not familiar with the CRT of the 475, I have to admit. The extra pins almost certainly are distributed plate connections. In general, there's just a terminator connected between both "ends". I did

It might be worthwhile to check and see if one of your -0731's will do. The 'scopes are very alike, except for BW of course and ISTR that CRT's of different models were used during the production life

Obviously, I meant Grid bias (3x). Raymond

If I understand correctly, you have a brightness and a (time base) deflection problem. There may be two problems or they may be two results of one (power supply?) fault. Did you try readjusting the CR

Depending on the voltage between grid and cathode, HV and PDA may be ok but still no light visible. Raymond

Are you talking about the HV (-2450V) or the HV multiplier (PDA) voltage output? Checking either (HV and PDA voltage) the way you did it is not a good indication of functionality: Since a neon bulb ne

I'd think that's way out of range for the electrical Geometry adjustments that you mentioned earlier, so probably something is wrong of the sort that Chuck describes. It may be worthwhile to quickly c

Possibly not: In the paragraph immediately following your longish quote the OP writes: "Y Align R1385 and Geometry R1390 will not bring the vertical markers into proper vertical alignment even though

I can't see why my text "I can't imagine you did" makes me call you a liar and your text "I already did" doesn't make you one since the manual clearly shows the answer to your question. In this group,

I can't imagine you did. You have the option to either use Autorange or set Manual ranging. The manual clearly shows that. Strange that "DM502A Autoranging DMM" and the writing "Auto" on the front of

Please explain in what sense "by modern acceptance of the term", it "clearly isn't autoranging". For more info, have a look at the Electrical Characteristics in the manual, available at TekWiki. Raymo

The nameplate shows "DM502A Autoranging DMM"... Raymond

It appears we found one. Raymond

- The 7904 has a primary switching power supply (PSU), so *no variac* allowed: You may overload (and damage) circuits while varying the input voltage. - If the PSU is in "tick mode" (it makes a tickin

This is the situation I had in mind in my post, though written down rather clumsily - incorrectly, actually. There's also the situation where the -12V is - for a short or long period - between say -6V

I'm under the impression that the OP thought he'd solve his problem by replacing the NVRAM with a nice, clean one. You're right that he came up with the idea but our reactions didn't make it clear tha

Please forgive me for asking but I can't quite follow. The OP told us that his 'scope was working fine but that he hadn't been able to resist the temptation to enable "cal" mode and play around. That

... nor the motivation to dive into it... Raymond

Just a hunch, didn't study the schematic much nor thought this through but low -12V (closer to 0V) would lead to Q32 conducting from ca. -7.5V (?), pulling down on R30 (point 10). Could this stop the