I'm trying to fix my '73 Zenith 25CC25. The problem is that the horizontal sweep is not wide enough, so my picture is compressed horizontally. I've lost about 10% of the width on each side. Other than that, it's fine. I have both the Zenith service manual and the Sam's for this set.
I've tried other hor osc tubes (6U10) and hor out tubes (20LF6) and none of the ones I have (which should be good) worked any better (but some were a bit worse. Not too surprising.)
This is a hybrid set, with 3 Zenith Duramodules. I have spares for each module, but swapping in the appropriate spare made no difference.
I checked the B+ in the Horizontal stages, and it's fine, 274 V.
The Vertical also seems fine, but I just tried to check the 2nd anode voltage, and got garbage readings from my HV probe. I'll take that probe to work tomorrow and check it to see if I can nail down that problem. It says I only have ~6800 V, which seems impossible. It's supposed to be 26 kV, so if it was really that low I believe the vertical sould be WAY overscanned, which it's not.
I've checked a few resistances that I can get to easily, and so far they all seem good.
What I haven't done so far is try to get a scope in there to look at the signal at each stage, so at this point I don't know where the problem starts.
I'm hoping someone here will still be familiar with this old set and can suggest some good places to look next.
thanks,