1966 GE PortaColor Restoration

[Dubis7]

Hey, so any help here would be appreciated. I need some guidance on how I can go about testing this next component.

I've discovered that the SAMS numbers don't line up with the numbers stamped on the bottom of the Portacolor. that's going to make this much more difficult to test at the component level when I'm working from the underside. Does anyone know if there's a rhyme or reason to match them up?

Second point: I'm almost certain my problem is related to the ringing color circuit. It was previously called "infamous" which I assume means this is a common source of trouble. My tube outputs all have the correct voltages, or at least in range, and replacing both the Chroma and Color amps had no impact.

So here's what I'm thinking: knowing that my burst gate signal is present (or at least operating at the right voltage), and pin 10 of the 8BU11 is still outputting a voltage in a tolerable range, my problem is likely to be either:

1. The crystal
2. The 2.4 pf capacitor marked at C80 on the SAMS schematic
3. The 220 ohm resistor marked as R93 on the SAMS schematic.

I have no means of testing the crystal, but Moyers has the part so I'll plan to test the other two and, if those are fine, I'll replace it.

Here's the thing, though. While I've identified R93 on the top of the schematic, it looks like the crystal is buried under a shield which in turn is blocked from the underside by the plastic support running down the center. So that's my second question: Are there any tricks to getting at this thing, or do I need to tear this down further to pull the whole unit apart?

Again, I'd be incredibly appreciative of any help here. I'm eager to get this working and I've made serious progress in figuring out where the problem ISN'T, but I want to make sure that as I get further into the weeds here I'm not doing anything that would damage any parts.

[Dubis7]

Realized I never updated this thread - the portacolor is working once more. I can't tell you exactly what was wrong, I fiddled around underneath for awhile, swapped the crystal and discovered that the pinout was different, swapped it back to the original and the color was back.

I had also touched up a few solder joints around the tube sockets while I was down there. It's been stable since so without having actually replaced any parts I'll suppose that there was an intermittent cold solder joint somewhere that I caught. Unless it comes back.