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#1
08-26-2005, 03:56 AM
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roundie color off
My color to RCA roundie is off, any suggestions, areas to look?? Crank down monitor bightness if picture washed out.
Last edited by vintagecollect; 08-26-2005 at 03:57 AM. Reason: . 
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#2
08-26-2005, 06:10 AM
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It looks like you're missing the luminence information and are only seeing the chroma info. I'd check the video circuits starting at the delay line and on out to the crt.
__________________
"proximo satis pro administratio" KAØSCR
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#4
08-27-2005, 04:08 AM
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what does switch look like???
what does service switch look like??? Pic Please!!!
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#5
08-27-2005, 07:12 AM
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What chassis model of set is this?
The really old ones like before ctc-11 did not have a service switch. The early-mid 60's sets like from ctc-11-16?? had a 2 position slide switch, one for normal and one to collapse the picture to a horizontal line for setting screen controls. The later 60's sets have a pull out type switch with 3 positions usually... normal, raster (blank raster for setting purity) and service (horiz. line) The service switch is always in the vertical circuit and sometimes in the video circuit.
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#6
08-27-2005, 07:28 AM
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Without the model type/number and the schematics we can't give you a heplful instruction.
The screen shot looks like a failure in the luminance amplifier circuits behind the separation of the color signal. Usually such failures are easy to fix. In some cases the true failure is in the A.G.C. circuit. See http://audiokarma.org/forums/attachm...chmentid=28089 It looks like a failure in the luminance unit, but it was the A.G.C.! You can test it by detuning the received TV channel. If there is snow on the screen when I receive no video signal, the luminance amplifier might be OK.
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#7
08-29-2005, 02:52 PM
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Yes, video goes off when color turned down
You guys are great for info!! What specific stages should I pay special attention to??? I double checked the Chroma circuits -----what about the Bandpass stages(is this the lumenence stage????) & others to look at??
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#9
08-29-2005, 05:55 PM
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The CTC-10C has a service switch. Mine gets intermittant every few years. A good cleaning always restores it to running fine.
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#10
08-29-2005, 06:53 PM
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Check the delay line for continuity.
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#11
08-29-2005, 07:05 PM
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check B+ to video circuit
as I remember sometimes some of the 5w resistors would open up supplying B+ voltage to the video amplifier. The 1st thing to do is always check for proper power supply voltage, you could have an open electrolytic cap.
__________________
[IMG]
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#13
08-30-2005, 02:01 AM
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good info
I have recently double checked status of delay line = good. Will see if voltages off value. Double check status of caps even though they are new.
Is the "Y" stage also known as the Band Pass Stage??? please reply with answer- need confirmation.
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#14
08-30-2005, 02:47 AM
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Ok, If it's a ctc12, ctc15 or ctc16, the service switch is on the back of the chassis ind is a *two position slider* that goes sideways. There are also 2 slide switches that go up and down, one for video peaking (sharpness) and one for "kine bias" (CRT bias). These two have about 4 positions each. I think the service switch is between them.
The "Y" stage, or stages actually are the video amplifiers. There are three of them. The first two are in the same tube. This tube is on the IF board. Looking in the set from the back, the IF board is the one toward the front and to the left, and shielded. It's the tube at the right of this board. The 3rd one, the video output, is a 12by7. It's on the chroma board. Thats the biggest board (back close to you). The 12by7 is at the far left of this board. If it's a ctc7, ctc9, ctc10, or ctc11, likely none of this applies except the part about the 3rd video tube being a 12by7. If it's a ctc20, likely none of this applies at all. The bandpass amp is part of the chroma stuff and is probably working fine, judging by the pic you posted. It's not a "Y" stage. Best of luck, John Last edited by blue_lateral; 08-30-2005 at 02:50 AM.
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