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Old 09-10-2014, 10:56 AM
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bandersen bandersen is offline
RCA 741PCS
 
Join Date: Mar 2009
Location: Chicago, IL
Posts: 8,808
Quote:
Originally Posted by robert1 View Post
since i don't have a diagram to look at for that chassis, i could only ask a couple of things. is the horizontal drive control a adjustable coil?, or a variable capacitor? or a pot? if it is a coil type, usually, those have a capacitor across it. it might be leaky. the coil itself, may have shorted windings.

have you checked the current on the cathode of the 6BG6?

i still suspect that red disk capacitor underneath the damper tube socket.
it appears to me that something is drawing too much current in the output stage. it might be that the flyback xfmr may a a few shorted turns or any of the above mentioned things, it also could be caused by a problem in a different circuit protected by that fuse.
You can download a copy of the Sams here: http://www.earlytelevision.org/pdf/C...Sams_160-2.pdf

The drive control is a pot. I'll try replacing the cap and measure all the voltages and waveforms in the horizontal circuits..


Quote:
Originally Posted by truetone36 View Post
Nice to see you making progress, even though there's been a couple of bumps along the way. When you get the bugs worked out, shoot me a PM and I'll get those knobs and the nameplate/control cover out to you.
Thanks, I sure will!

Quote:
Originally Posted by HighHopes View Post
Hi Bob,

I have a question about the small test CRT tubes you use. After you get a set to work with a test tube, do you need to readjust the set again when the full sized tube is installed?

Also, I am thinking these tubes do not use an ion trap, true?

Is the focus coil a problem?

Steve
Yes, you need to readjust, the height, width, linearity etc. They do not use an ion trap and are self focusing.

Leaving the focus coil in place does produce a blurry image. That's why when I unmounted it in the photos above the picture improved.
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