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Rca ctc-53x
Just got a RCA model EX 417WR Remote control tv with CTC-53x Chassis. Uses low voltage focus crt 18VDP22. I have poor focus and not sure how to correct this. There is no focus pot however the wire leading from the focus pin of the crt has three placement positions. One pos. is 0 volts another is 310V and last is 790v. There is a resistor inside the picture tube socket and measures correctly. The 0 volts provides best focus but still out of focus. The high voltage is higher then normal about 22k. There is a strap that can be cut to make high voltage higher according to RCA service guide. Voltage 22k when strap was attached. 25k not straped. Hoping someone can help with this focus problem.
My line voltage is a little high around 123VAC. Perry |
#2
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One of the forum members suggested a very mild rejuvenation. When those CRT's are a little weak, the focus isn't that great, even though the gray-scale might be good. I never tried it, your results may vary. |
#3
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Beltron would help.
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#4
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Almost always its the CRT. A LIGHT rejuve will perk things up
but low focus jugs need everything perfect to look good. I would NOT use a Beltron on it. Its the brute force way. Beg borrow or steal a modern checker from the 70's up that has a "clean & balance" setting like a Sencore or B&K. Also if this is the hybrid chassis watch out for resistors in the hoz osc. The go up in ohms & eat horz outputs without any symptoms. 73 Zeno LFOD ! |
#5
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Ctc-53
Thanks members. I used my B k on clean and balance and now I have a decent focused picture. This is a striped down tv. I think RCA's version of a porta-color.
No HV Pot, No focus control, AGC, Blue, Green drive. series string. Surprised that the company known as the pioneers of color would produce this crappy set. Looks OK but not a performer. Nice it has remote control. Perry Last edited by iong; 01-26-2018 at 09:08 PM. |
Audiokarma |
#6
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I have the 14" version, CTC51X. The picture isn't quite as clear as it could be. |
#7
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If this is the all tube set ( also in 14") they are VERY tube hungry
& suffer from dried intermittent sockets too ! Its just to damn hot in there. I have taken a few of them & changed the low level tubes one at a time & saw a small improvement with almost every one. When done if it has a good jug the pix can be fantastic. ( you need a sleeve of 5GH8's !). Compactron sets were the same way....... Last one I did was a favor* set. Girl that worked at the Deli & made our coffee every morn. She did have an awesome rack but her OM made more than I did. Boss said the tubes were obsolete so fill her up no charge. I did & that set came out SWEET ! * favor set. A set belonging to someone poor or down & out. ALWAYS a dried up & worn out set, usually a console with a "beautiful" cabinet. Guarantied to loose you $$ and have difficult problems. The word NO has no meaning to the owner. And when done you charge a token fee, about 1/10th the normal bill they dont even thank you ! 73 Zeno |
#8
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Last edited by andy; 11-18-2021 at 05:02 PM. |
#9
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Ctc-53
I now have good focus and brightness however my high voltage is 24k and I can't get it lower. Should be max 22K. Think I need to check resistors. I'll have to get a Sams. The RCA service manual has a slightly different 53x diagram.
Perry |
#10
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I would rather have higher HV, than not enough. Two KV is not too high to worry about. If the rest of the set seems to work alright and focus is good, it should be OK. |
Audiokarma |
#11
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Ctc-53
There is a strap in parallel with a resistor on the Horz output board. This is the only high voltage adjustment. Rather the strap is connected or not there is no change in the high voltage at all so there is clearly something wrong. I guess i need to check the components but I need Photofact 1271. There are a few different CTC-53 chassis with slight differences in high voltage section.
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#12
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Last edited by andy; 11-18-2021 at 05:02 PM. |
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