RCA 621ts Restoration

[vts1134]

Originally Posted by old_coot88

To check resistance of the -110V source to ground, just look for a DC path to the nearest ground symbol in the schematic (hint: it goes thru the ion trap coils), and add up the values of the resistances in that path. And see if the sum agrees with the ohms reading you get on the meter (+/- 10% or so).

Such an easy answer to my question. Seems silly that I had to ask, but now I know. All of the resistance readings on the negative sides of the capacitors read correctly.

Originally Posted by old_coot88

Hmm.. so the power xfmr CT is the negative voltage source*, supplying 110V negative for stuff elsewhere in the chassis. And the main filter for it is the 40mf.cap (square symbol). Can't read it too good, but i b'lieve it's C128A). The positive side of this cap should go to ground. Is this wired correctly? If it's not, the negative supply would have a large ripple on it. So check this first, and then check for ripple. And verify that there's 110V negative on it (+/- 10% or so).

This is wired correctly, and there is -110v present.
I believe that I am checking for ripple, but perhaps I have the test wrong. I have put my meter on an AC 4v scale. I've connected the ground lead to chassis ground and the probe through a .1mfd cap to negative on C128. Is my test correct, and am I seeing ripple on the meter?
http://www.youtube.com/watch?v=b5BBxQlqp1o