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#17
07-11-2015, 09:50 AM
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Dumb question, but you have subbed the h.oscillator tube, right?
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#18
07-11-2015, 01:42 PM
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Quote:
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Bruce
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#19
07-12-2015, 02:23 PM
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#20
07-12-2015, 02:25 PM
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#21
07-12-2015, 03:08 PM
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Oh, be aware that it won't work right if you have the replacement diodes, one or both, in backwards. Carefully remove them from the circuit board (so traces don't peel up) and tack solder the old diode package back in.
You want to avoid creeping layers of errors and defects from making life harder.
__________________
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#22
07-12-2015, 06:10 PM
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Lets keep in mind what seems to be going on.
It seems when cold the pix has lots of lines. This IS the hoz osc off freq. No question........ I assume as it warms there are less lines then the pix comes in but is trying to float side to side & is very touchy. First thing is to get the osc stable. Its probably a cap but check all the resistors also. You can use freeze mist on the caps. Just a little on one at a time. Too much can cause a good cap to drift. After it warms back up move to the next cap. After you get the osc stable if its still trying to move side to side start checking around the diodes. Also there is a sample pulse coming from the flyback to the phase ckt. Check that, resistors are often stressed there. If you can also post the hoz part of the schematic, a big help ! 73 Zeno 
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#23
07-12-2015, 09:35 PM
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Okay, I took a short video of the horizontal not locking in...
https://www.youtube.com/watch?v=7Gtz...ature=youtu.be I also added the horizontal section of the schematic... I have replaced all capacitors, less disc caps, and replaced most of the resistors, and left in those that measured correctly. I believe the diodes are installed correctly, the cathodes, (banded ends), as common, both ends I soldered in the middle , where the middle leg of the dual diode was soldered in. Replaced the Horiz. Oscil. tube, a few times with different strong tubes. I also used Deoxit in the hor/hold pot. Nothing seems to be working?
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#24
07-13-2015, 07:17 AM
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this is why a video is needed. Its not the AFC diodes at all. The horz osc freq is way off and no amount of sync signal will help. in other words this is not a "locking in" issue. Locking in implies a horz freq that is near the correct freq but not synced up to the video sync signals.
I would suggest you put back what ever you took out there just to reduce the number of variables. Last edited by DaveWM; 07-13-2015 at 07:28 AM.
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#25
07-13-2015, 07:25 AM
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Next would be did you try adj the horz osc coil. if its working this should change the freq (and number of lines to fewer until it can be momemtary lock anyway).
Did you confirm the values of parts that have been replaced so far. Did you replace the cap across the horz hold coil. Did you confirm the value of that cap, did you make sure the replacement cap that was used was good? did you make and adjustments to the trimmer cap? any parts that have been replaced should be double checked to make sure you did not make a 10x error.
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#26
07-13-2015, 08:41 AM
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EXACTLY !!
If you try the hoz coil first clean the customer control R6b & put it dead center. Put a flag (piece of tape) on your alignment tool so you can count the turns & go back if need be. 73 Zeno Quote:
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#27
07-13-2015, 12:33 PM
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If the osc. coil is soldered to the board check for cold or cracked joints at it's terminals, I've had troubles with board mounted coils developing bad joints and strange problems resulted.
__________________
Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4
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#28
07-13-2015, 12:52 PM
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other thing to check, the horz hold pot, make sure one side is not open. I like to use analog meters to check the action as well as the continuity of the end terminals. Analog meter movement is a better tool for evaluating the action, than a digital meter. confrim the voltage divider resistors that feed it as well. Dont forget to confirm ground connection of that pot as well.
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#29
07-13-2015, 03:15 PM
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If the h.freq. coil has a hollow slug requiring a hex alignment tool ('diddle stick'), be sure the correct tool is used. Otherwise you'll fracture or split the slug making it impossible to turn.
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#30
07-13-2015, 03:19 PM
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Quote:
__________________
Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4
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