Digging into the CTC-9

[zenithfan1]

Originally Posted by andy

Considering how it ages, I'm not sure why anyone would want to add new PVA. I just use some foam mounting tape in the corners as spacers (usually 2 layers thick), then seal the edge with silicone. After it's dry, I go around the edge with packing tape for a little extra strength. The safety glass will still do its job without the PVA, there will just be slightly more glare with an air gap.

+1, Also, trying to replace that PVA would most likely end up having air bubbles trapped in it. Sealing it back on the way andy says works beautiful.

[leadlike]

Well, my next step was to mess with the HV. After getting the spare crt installed, I noticed the HV was normal, but I noticed that I couldn't advance the HV beyond 20kv. The picture looked a bit out of focus as well.

The next day was a bit more humid, and on power up, I heard some spitting coming from the cage. Opening up the cage while under power showed some nice corona all around the 6BK4 cap and lead in. The rubber on the wire was all dried out, and the cap was very crumbly.

Well, the Zenith roundie had provided a good crt, why not some HV hardware, too? I pulled the RCA's lucite HV cup, too-as it was warped. Surprisingly, the Zenith's HV cup went right in-they were a perfect match! While the RCA's 6BK4 cap was like any other tube cap, the Zenith's is a massive insulated sleeve that covers the whole top half of the tube. The wire lead is also heavily insulated. With those in, I could ramp up the HV to just under 40 KV! Not that I kept it there.

Now I have a pretty well-functioning roundie. I can now dig into convergence and color balance. Any tips on these settings? What should HV be set to? Can I damage the crt by cranking up the Drive/G2 controls too high?

[zenithfan1]

Originally Posted by leadlike

Now I have a pretty well-functioning roundie. I can now dig into convergence and color balance. Any tips on these settings? What should HV be set to? Can I damage the crt by cranking up the Drive/G2 controls too high?

The HV should be set at 25Kv, and yes, you can damage the tube by turning the controls up too high. If you see retrace lines, back it off until they disappear and then just a hair more. The set ups for it should be outlined in the sams folder.