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Old 10-02-2018, 03:58 PM
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etype2 etype2 is offline
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Hi Mike and VK members,

Great news. I think the nominal ultor voltage for this set is 19.5 KV?

I’m told the convergence transformer in question is identical to RCA.

Best,

Marshall

Yes, that is what the nominal HV should be at the 2nd anode. The actual HV generated should be, I think, more like 22.5kv or more. This is due to the function of the 6BK4 Shunt Regulator that keeps the regulated voltage at the 2nd anode at roughly 20KV at all brightness levels. The overhead voltage is so the shunt regulator can do that job at different beam currents. I made this test with no shunt regulation at all. I believe that the initial HV will come up quite a bit after some recapping and tube replacements like the 6BG6 Horizontal output tubes. I still have to go through the tubes and test them all. But this tells me that it is now OK to move forward with the whole project.

Can you go ahead and arrange the convergence transformer purchase? Or are there none left to be purchased? Do I have to build one?

Cheers, Mike


Mike,

I’m glad that we can continue to proceed with the restoration! :-) I’m not sure what the issue is with the transformer. A VK member said “The dynamic convergence transformer is T-701. It needs to be replaced with a Folsom reproduction ASAP, before you damage pots in the focus circuit.” Further, its the same as used in the RCA CT-100. Apparently the part is near impossible to find if bad.

Another VK member said it’s doubtful that John Folsom has a replacement because the last one was sold to a collector. I contacted John a week ago with no response, perhaps my mail went to his junk folder as I haven’t corresponded with him in quite some time.

We don’t know if our transformer is bad? It’s called the vertical convergence transformer T-701. When you reach that point you can test, no? I will post this on VK.

Cheers,
Marshall
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