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Ok tuner cleaned and ruled out no more flickering. So now even though it’s said not to take things to be right in sams like the voltages the Motorola schematic shows voltages higher then sams so the next thing is I really need to find out why the voltages are so low in this set even after 15 minute warm up.
275v=256v 190v=177v 145v=140v 640v=539v 770v=750v Motorola shows much higher, these voltages are just to low something is not right. Pin 8 of v6 is supposed to be 230v but it’s 110v so if the main power supply voltages are low so is everything else. I had already checked out the power transformer and found it to be fine and 15 minutes is long enough for the thermistor to heat up and I had checked that as well IIRC it was 1 or 2 ohms. And all this is checked with 121v at the outlet. |
Again, no 2 sets are alike, so you should never take the voltages listed in the SAMs as an absolute, variances of 5-10% is normal.
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If all are off by 20 percent then none are pointing you to a particular trouble. The ones that are off by a much greater percent are telling you where to concentrate your trouble shooting. Pick one at a time to work on, and eventually you will fix one and then another. |
This is as much video I have got so far from the sets own tuner but is there another area I could look into like maybe the blanking amp judge by what the image looks like since I turned the IF coils one at a time and kept count in or out but if I turn them I start to lose the video so I left them alone. I’m just trying to figure out if another circuit besides the agc could make this image like this. No change in turning the agc little difference when turning the noise gate.
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If agc can distort and mess up video shouldn’t it kill audio as well.
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The posted pics are still a very strong sign of a IF alignment problem. The picture almost looks negative, much worse than when fed in at the 2nd IF or test point A.
As many will say, you can NOT adjust the IF visually, simply tweaking a coil a bit to see if it improves what you see on the screen will get you no results, as they interact with each other, the entire process must be followed with a rf frequency generator or sweep marker generator anything else will just make is worse, as anyone else can tell you. |
Yes the video looks like a negative but the pic I posted back a few pages was done with the subber on pin 2 of v2 but since changing the 22ohm resistors in v1 and v2 I am not able to get that back again not sure why
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It was said in a previous post that if the trap at the antenna input was bad it would be impossible to tune anything in so with that said if the trap were good then if it’s turned in either direction it should change what’s on screen already to at least some degree this one does nothing at all and yes I marked exactly where it was before touching it. Is there a way to tell if it’s bad sams says it’s a 15k pot which it is a pot but it only uses 2 connections no center wiper so I guess it varies the 15k itself from under the adjustment knob.
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That almost looks like a detector circuit problem.......
Does it get sound? noise that changes with channel selection? I think maybe you should contact a Priest and get an Exorcism for this tv...... . |
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The 3 pictures you posted above look to me like the delay line is open, and you are
just getting the color portion of the picture to the screen. Only in this instance it looks like there is no color..... Does the color control, tint, or contrast control have any effect on the picture? If any what does each control do? Be specific to each, and the effect. be clear in your description. Is the detector diode in there correctly, not backwards. Are each coil close to the correct resistance? Voltages on the Video Amp & Output ok? Is the sound crisp & clear, full tone no noise mixed in etc..... Full clear volume? . . |
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This is the latest don’t know why it flips.
Video amp 9-172 7- 13 8- 116 6- 14 Video output 7- 250 6- 153 2- 11 1- 11 |
Is it possible the video detector diode has gotten reversed? (I haven't read thru this whole tome, so this might have already been asked.)
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