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#1
05-05-2009, 06:42 PM
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tuner subbing
I replaced the paper and filter caps on my ctc5d. Also replaced resistors that were out of tolerance. I tried running the set,and all I have is raster and noise out of the speaker but not what I was trying to watch. So, I will diagnose the set next by running it and checking voltages. The cable coming from the chassis to the tuner that caries the signal is a RCA jack,(if that 's the correct term). To bypass the tuner for testing purposes can I hook that cable to the back of a DVD player?
Last edited by radio nut; 05-05-2009 at 06:43 PM. Reason: can't type very well 
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#2
05-05-2009, 07:38 PM
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That won't work, as the tuner output in sets that old was the video intermediate frequency (IF). Basically, it's the TV channel converted from its original frequency to 41 to 45MHz in more modern sets, or 20 to 25Mhz in very old sets. But this signal hasn't been demodulated yet.
What may work is to grab the tuner output from another known working TV set. One that uses the same IF frequencies. Make up 3 cables with F connectors on one end, and RCA connectors on the other. and use a cable TV splitter, the source tuner feeds the splitter input, and one splitter output feeds the source tuner's own TV set IF input on its chassis as it did before, and the other splitter output feeds the TV under test's IF input. The source TV tuner still needs its B+ and AGC control lines, and the source TV chassis will provide its tuner with these. And the source TV will present video on its CRT, and sound, so you know you have a TV channel tuned in. Conversely, as another test, to see if the color TV's tuner is working, make it the source and do the same splitter trick with its IF output with the splitter.
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#3
05-06-2009, 08:52 AM
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I use a Tuner Subber that has been here for years and indispensible. It is a solid state tuner in a box with a potentiometer and a couple of batteries. The poteniometer varies the AGC so it can interface with the chassis better. I have seen them on EBAY now and then. If you have an old rotary transistor tuner it could be used if connected properly with batteries
They are time savers to say the least. I just looked, mine is by Castle Tuner.
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