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  #106  
Old 10-19-2017, 05:05 PM
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I have the CT-100 coil list around here somewhere, whoch should be identical or pretty damn close. Keep in mind that those little white inductors have a different Q than the modern replacements and that can have an effect on performance.

I'll go look through my file cabinets when I get home.

As for your second question, I have to answer that with a question: do you plan on running the set right off a wall plug, or do you plan to only run it on a variac or Sola at say 115 or 117 VAC?

I highly recommend you hold the line voltage to 115 or 117 volts whenever running the set, and calculating the new dropping resistors for 115 or 117 volts.

You can, however, calculate the new droppers for whatever the line voltage is in your neck of the woods, say 122 VAC or whatever.

Small changes in line voltage creates a larger swing in B+, and the 21-CT-55 flyback already has a tendency to overheat and burn up. Whatever you do, make sure the droppers are sufficiently sized, and the horizontal section has been completely checked before moving on to other areas of the restoration. I'd hate to see your fly smoked from B+ that was a touch too high.
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  #107  
Old 10-19-2017, 06:33 PM
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A few hours ago I found Nick's coil list and edited my post to reflect that.

I've got a 1KVA VRT isolation trans waiting for it. I may put a variac in series to set the line voltage if I don't like what the VRT is putting out. The mains voltage here varies a bit so most tube sets end up run off a VRT anyway.

It will be a while before I get to working on or finishing this set. Plan is to order enough parts for several sets (some of which may be done first), plus replenish my cap stocks to nominal quantities, as a winter stock up. I'm seriously considering restuffing all the caps in the 21CT55 which is going to take time as is checking everything over before power up. As with any early color set with an unobtainium flyback there are going to be a lot meters on it for the first power up with the H out tube connected.
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  #108  
Old 10-19-2017, 07:07 PM
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I don't restuff as I feel there are few, if any sets, truly worth the effort. To each his own though...


About the inductors, the original white ones are obviously the best fit electrically. Check them and any that aren't open, leave. Some more may open during the restoration, but if any survive, they're worth keeping in my opinion given my experiences with my CT-100 (now John's).
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  #109  
Old 10-19-2017, 10:13 PM
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Not sure what troubles you had, but this is my Merrill after total inductor replacement with the new ones from the list I put together. Looked pretty good to me.



Crappy picture and there’s a hint of a drive line, but the color was stunning.
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  #110  
Old 10-20-2017, 08:55 AM
WISCOJIM WISCOJIM is offline
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Quote:
Originally Posted by Electronic M View Post
I've got a 1KVA VRT isolation trans waiting for it. I may put a variac in series to set the line voltage if I don't like what the VRT is putting out. The mains voltage here varies a bit so most tube sets end up run off a VRT anyway.
You should get one of these for each of your sets.



(see thread: http://www.antiqueradios.com/forums/...?f=15&t=209410)

.
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  #111  
Old 10-20-2017, 10:59 AM
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Quote:
Originally Posted by WISCOJIM View Post
You should get one of these for each of your sets.



(see thread: http://www.antiqueradios.com/forums/...?f=15&t=209410)

.
That's just a rebadged Sola CVT, and it can't supply the necessary current to a 21-CT-55 anyway. The Colorvolt came out in the late 60s and was limited to about 3 amperes, so about 350 volt-amperes of apparent power.

A CT-100 draws just a hair under 500, I think the 21-CT-55 is about 540 or so. A CTC-4 draws 375 watts, the CTC-7 and 9 chassis are in the vicinity of 360 watts. A nice thought, but not really practical for any 50s roundie. A nice 750 VA or 1k VA unit is superior.
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  #112  
Old 10-20-2017, 02:15 PM
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Quote:
Originally Posted by WISCOJIM View Post
You should get one of these for each of your sets.



(see thread: http://www.antiqueradios.com/forums/...?f=15&t=209410)

.
I sort of do....I don't have that exact model that turns it's self on and off, but I've got 4 outboard CVT/VRT units (2 250VA units, a 500 and the HEAVY 1KVA unit), and I've been using my VRTs with remote switched outlets...So in the end the function is similar only I don't have to get up to turn it on and off.
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  #113  
Old 10-21-2017, 07:27 AM
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Quote:
Originally Posted by miniman82 View Post
Not sure what troubles you had, but this is my Merrill after total inductor replacement with the new ones from the list I put together. Looked pretty good to me.



Crappy picture and there’s a hint of a drive line, but the color was stunning.
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