[TinCanAlley]

Originally Posted by BeamT

While troubleshooting by substitution can be a strategy, replacing large swathes of parts can have a real risk. At some point in time you can find yourself with a set that doesn't want to work right, and unraveling layers of parts and changes can be extremely difficult.

In the end this is your set and your journey!

Always wait for the DeoxIT to evaporate and dry before you energize.

Diodes can be leaky, the horiz blanking diode CR201 would be a good part to substitute. This needs to be a fast switching diode like a ECG177.

I would take some time to look at the voltages on the Blanking Amp Q202, Vertical Blanking Amp Q217, and 3rd Video Amp Q203. The line between the collector of Q217 to the base of the Blanking Amp Q202 gives you a perfect place to scope the blanker at both the vert and horiz rates. Good waveform to look for in the SAMS. C204 and C202 are critical to horiz blanking.

Were any of the resistors in the Blanking circuit out of tolarance?

Out of curiosity does the Peak Pix control work?

Does this set have a separate focus divider?

Each of the subs were tested earlier in the set. I swapped them in and out until I was certain they all worked as expected. Just never go around to doing the permanent swaps. Now I have and it won't be hard to figure out which one if any fail. I still have all the previous parts.

I can scope them again. I did this back in 2013 on all those outputs and they measured at rated voltages. I also replace CR201 back then and still have the one I removed as the new one didn't help issues, so the old one is still good. Last go around I replaced the 750V Boost diode, Damper diode and Horizontal Blanking. The only other diode I was supposed to change, but didn't, was CR202 Zener Diode 24V across the emitter and collector of Q204. I have that diode and it would be an easy swap.

I'm going to order those two capacitors you noted as I was eyeing them myself, but is wondering what other pieces I might want as I'd like to maximize the order to justify the crazy shipping rates now.

The peak Pix works, the resistors in the horizontal blanking circuit were replaced and it does have a separate focus divider. I replaced that shortly after getting the set as it would sizzle on humid days and upon inspection it was drying and cracking.