Carbon composite in place of carbon film

[TinCanAlley]

Originally Posted by DaveWM

I checked my manual the white green should be 22v pp close enough to sams 20v.

you need to calibrate the scope use a 9v battery if there is no calibration point on the scope (more modern ones have a 5v pp square wave generator to test to). put a 9v battery and note how far a trace deflects, adj the vert amp to get a size that is easy to work with and will nearly fill out the screen on the scope if it was 22v (so make the 9v move the line little less than 1/2 the screen that way a 20v spike will nearly fill it. There are markings on the screen if you try to use those to represent 1v each.

increasing the sweep rate should let you see fewer spikes. I dont know much about scopes only the one I have, so not sure how keying works on yours.

This might be a stupid question, but should the probe be plugged into the vertical input or the horizontal? I am unable to get a decent size display with the horizontal input, but with the vertical input I can expand to fill the screen. Only issue is, I believe I need the horizontal input because we're aiming to check the horizontal circuit, right? If that's the case, I think this old thing is in need of repair.

Now on to the setup issue. I decided to check the red G1, G2 and screen voltage both in and out of setup from the pins on the CRT. I figured that if the line wouldn't come up at all for the red, it was the best to check. Here's what I got.

The first number is in normal mode and second is in setup mode:

G1 = 161, 192
G2 = 605, 612
Scr = 33.6, 34.3

Now the G1 is supposed to be 140V and the G2 should be around 590V. The Screen voltage is supposed to be around 36.4. Except for the G1, all numbers are pretty close. I don't know how much voltage difference is allowed for G1, but if I understand things correctly, it's voltage varies in conjunction with the G2.