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Originally Posted by Steve K
Here is the horizontal section of the CTC-7. I also have the schematic for the 9. Is this the only part you wanted to see or would you like the entire schematics?
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Steve, please send me the schematics for the ctc-7 and for the ctc-9 if you have them in a digitized form.
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Originally Posted by roundscreen
Mistakes, don't ya hate that. 450 ma now thats some horz drive. When I solder boards I take a small screwdriver and scrape the board around the traces and connections I worked on. Since i am a walking mistake I double check all the work I do.
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Usually I take a small screwdriver too and scrape the board around the traces and connections I work on. But the boards of this vintage set are very old and I thought that I would damage it by doing this. Therefore I didn't do it this time. You know the results. )-:
But I'm very happy that nothing more was destroyed and hope so. This I thank you, because I had always running the meters and I see on them that something unexpected happened very fast. If I hadn't run the meters I probably had first noticed the defect when smoke and fire came out of the chassis.
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Originally Posted by Bill R
Sounds like you have it. Nice work.
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Yes, it seems so. I noticed that the control range of the horizontal frequency has become smaller. When I turn the core of the horizontal hold, the brightness is getting darker or brighter, I can see that this has an effect on the horizontal output drive. In the momemt I can only display a tv program with CCIR / Gerber format, i.e. 50 cycles vertical and 15,625 cycles horizontal scanning lines. When I try to display NTSC and adjust the horizontal hold up to 15,750 cycles, horizontal frequency is disturbing by small interupts, i.e. there are misfires in the frequency with bright sparks in the middle of the screen. With 150k (R603) the 6CG7 might be overloaded. I have just the exact voltage values in the horizontal oscillator unit of the set asccording to the RCA manual.
But I have received now the complete Sams Photofact papers for the ctc-5 in jpeg-files. (Please PV me if you want it too.) In the Sams the schematics are more detailed and with different voltage values than in the RCA manual. Here are they (in brackets are the values of the RCA manual):
Pin 2 of the 6CG7: -15v (-27v)
Pin 3 of the 6CG7: 10v (5v)
Pin 6 of the 6CG7: 215v (235v)
Pin 7 of the 6CG7: -70v (-88v)
Pin 3-6 of the 6CB5: 6v (7.5v)
Pin 4-5 of the 6CB5: -30v (-40v)
One can see that the values of the Sams are lower than the RCA values. The RCA values are border values in my opinion. I would lower the resistance of R603 down to 130K or 120K to avoid overloading of the horizontal oscillator.