Hey y'all, I set up my PET 2001-32N for the first time in awhile, and with newfound confidence, I decided to tackle the issues plaguing the unit.
The most glaring of which were the following:
- The picture feed on the display would drop out, and come back with a smack (figured it was a solder joint)
- The top line or two of text would be squished horizontally (sounds like a capacitor)
- The top few lines of text wouldn't be at the very top of the screen, and would also be squished vertically
I put it on the bench, opened it up, and replaced electrolytic capacitors C3, C9, C12, C13, C15, C17, C22, & C23, which has solved problems #1 & #2. I would have replaced the remaining 3 electrolytics if i had them in my stockpiles. Problem #3 was not solved by the capacitor replacement...
So I cranked up the brightness knob past where you would normally want to set it, and the horizontal lines across the screen showed me more about problem #3. The whole vertical deflection is nonlinear.
I've hooked up my scope to a few spots to see what kind of wave forms I get, and they mostly look okay, with proper voltage ranges. But based on the crude drawings in the schematics, I'm seeing that the wave forms near the vertical yoke (pictured), and near the base of Q10 aren't quite the right shape.
Long story short, I'm not sure what the next step in my repair process should be. Any ideas what I should test & try next?