Capehart Troubles...

[jpdylon]

From what I can tell everything should be working.

The oscillator is working. I can get a 15.74khz signal at the HO grid pin 5 and 3, and you can hear it singing.

After everything warms up, I can hear a faint fizz at the CRT anode and in the HV cage. It fizzes again when I turn the set off. If I pull the anode from the CRT it doesn't make the noise. I guess HV is there, but I still cannot feel it on the back of my arm and hand as I pass it by the tube face. I thought I had good continuity on my HV lead to the rectifier, but I'll double check again.

After replacing R96 CRT voltage at pin 10 is around 350v. There is very little change when I disconnect the CRT socket.

Other than that, I'm not sure what else to do here. Perhaps the near dead tube is to blame. I raised the filament voltage to 9 volts on my CRT tester but the emission didn't budge. Its just a cooked tube. I've tried rejuvenation but its just no use.

I guess for now its dead in the water...

[wa2ise]

Does your CRT need an ion trap? If it does need one, and it's missing or misadjusted, you won't get a picture on the screen.

[jpdylon]

I've tried moving the ion trap around, but I don't see any difference, even in a dim lit room

emission on this tube is next to nothing

[jpdylon]

I confirmed that its the CRT this morning.

I was curious to see if the chassis was working the way it should. I found a 70 to 110 degree adapter and connected the chassis to a 110 tube I had in another project set. The CRT tested like new, so I figured if the chassis works, we should see light. I made a crude HV extension, connect the tube and powered up. I had no way of properly connecting the deflection yoke, so i just waited for the spot. BINGO! we have light! So I turned off the chassis, discharged the tube and breathed a sigh of relief. The chassis is working fine.

I was contacted by a member who has a 16KP4 he would sell me. At the end of the month, i hope to purchase it and get this baby working right again!

I love this place. Thank you to all who helped me troubleshoot the chassis.

[peverett]

I had a tube like that once. No matter how many times I tried to re-juvinate it, it had no emission. No shorts, etc, just no emission.

I found a parts set with a re-built CRT. This worked fine.

[kbmuri]

Jordan -

Just wondering where you're at with the Capehart. Thought this thread deserved a bump.

- Kirk

[jpdylon]

Kirk,

I received a good CRT from Tim. The chassis is near complete except for a vertical blanking circuit that I would like to add.

My only problem now is finding the spare time to get to the set. Working 6+ days a week makes it difficult to find spare time.

I may also attempt some cabinet restoration. The top has seen better days.

[kbmuri]

Jordan -

I know what you mean. I can only work on my sets for a few hours on Sundays if I'm lucky. That's why projects like my soundless Admiral drag on so long.

I'm glad that Capehart is in good hands, and nearly restored. I haven't seen another one yet, or I'd own it. Definitely a tough get. Make sure to post a shot of it working, sometime.

- Kirk