Prototype set is here

[John Folsom]

Possible Leaks in Metal Cone portotype color CRTs

1. Evacuation seal (copper pinch off type)
2. Wire to glass seals at base (not very likely)
3. Glass to metal seal at faceplate of tube
4. Glass to metal seal between neck and rear of metal funnel
5. 8 welded bolt heads which protrude through sides of metal bell, part of the phosphor dot plate and shadow mask mounting assembly
6. Metal to metal weld between front and back of metal funnel (similar to 21AXP22)

Summary: Lots of places for these tubes to leak!

[MelodyMaster]

Originally Posted by John Folsom

Possible Leaks in Metal Cone portotype color CRTs

1. Evacuation seal (copper pinch off type)
2. Wire to glass seals at base (not very likely)
3. Glass to metal seal at faceplate of tube
4. Glass to metal seal between neck and rear of metal funnel
5. 8 welded bolt heads which protrude through sides of metal bell, part of the phosphor dot plate and shadow mask mounting assembly
6. Metal to metal weld between front and back of metal funnel (similar to 21AXP22)

Summary: Lots of places for these tubes to leak!

Now this has me worried. The picture on the 21AXP22 in my Admiral 29Z1 (C322C16) was pretty dim years ago. I stupidly tried flashing the cathode, but that made no difference. I'm now wondering if the tube was indeed going soft. It needs a few tubes put back in and capacitor replacements before I can try it again. If the sulfide tube IS shot at least I have a NIB 21FJP22 to replace it with.. but those rich reds will be gone.

I had a 1981 Sony XBR in which the picture tube went completely to air after 8 years. At $700 in 1990 dollars for a replacement that was the end of it.

This is a fascinaitng thread. Thank You.