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Crumbtrail TV Forums: TV Equipment: Projection TV Forum:
RCA R52WH74 Convergence issue, good FL231 fuse, resoldered flyback

 

 


HostileHST
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Aug 16, 2012, 7:25 PM

Post #1 of 4 (3628 views)
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RCA R52WH74 Convergence issue, good FL231 fuse, resoldered flyback Can't Post

Before I messed with any part of the internals of the TV, the menu came up seemly fine, looked square, no pincushion affect (most the time), just blurry and would separate the colors after being on a bit. There would be times it would have the pincushion affect, but seemed so rare and hardly noticeable, so I didn't care to look into it. Auto Convergence worked at this point and would cure the color separation, but only temporarily. As the TV got warmer with continious use, the time before color seperation was sooner. Next day, the cycle repeats, so the cool down started giving me some clues and started leaning toward cold solder joints. After some reading, I did the flyback resolder trick. All seemed well, till I had to go mess with the TV more cleaning up as many solder joints as I could. I started on the long thin board the main AC power initially goes to before going to the flyback power supply board. Suddenly, after a simple solder clean up job, on just the one board, the dreaded pincushion affected the entire screen, including the menu's.

As a note, I have the same set as D-Rock3, with the ITC222A chassis. The pictures he provided nails mine to a T.

The board in question is mounted in the top section of the TV on the left side. My understanding is the board is the power supply for the convergence amplifier board (not to be confused with the flyback board). The board is getting 156 volts into it, but on the output side, I get 2 volts for the +53 output and 13.5 volts on the +15 volt output, seems the same for the -15 (-13vdc) and -53 (-2vdc) outputs. At this point, my question is about this particular board, what could be causing the voltages to drop so dramatically? I am not stuck thinking it's only this board, I am open to any suggestions that ultimately could be causing the pincushion or 3d affect as most put it.

Been soldering a very long time and am not afraid to venture into any part of the TV testing anything necessary as instructed.

Not sure if this helps, but I never could use the remotes up/down, left/right arrows to control the menu, but all other functions of the remote work and anytime I hit one of the arrows on the remote, the TV's power light would flash indication it was getting a command. A friend said it could be a corrupted remote and I honestly don't care if the remote is bad or not, I only mention it if it's a clue of sorts.

I have checked all 3 fuses repeatedly, even took FL231 out of circuit just for kicks and it still checked fine, resoldered the entire flyback board with my wife's help to ensure nothing was shorting and that all joints were reworked (3 hour job, OMG). Resoldered all joints on the power supply board for the convergence amps and resoldered all the joints on the long thin board the AC initionally goes to. I have no clue how resoldering one simple board could mess a TV up so badly. I've been kicking myself ever since for even bothering with anything more then resoldering the flyback and checking the fuses, but the TV still had issues and I am bent on fixing this beast, thus I "tinkered" it into it's unexpected demise.

The auto convergence tries to work, but quits after a few seconds (just trying to add as my possible clues).

To repeat myself, my personal question is about that lack of -15 +15 -53 +53 volts out to the convergence amps, but willing to look elsewhere as I am not totally stuck on this board being the only issue the TV is experiencing.

A mental note I had made was when checking the +15 output on the power supply for the convergence amps, that same 13.6-13.6 volts was the same as a resistor near the flyback. Not sure if the flyback section or anything the flyback is on, would affect the voltage to the power supply board in question. Obviously, I am theorizing with my britches down with a nice gust of tail wind.



jts1957
Veteran


Aug 16, 2012, 11:49 PM

Post #2 of 4 (3623 views)
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Re: [HostileHST] RCA R52WH74 Convergence issue, good FL231 fuse, resoldered flyback [In reply to] Can't Post

Read/study thoroughly, ask questions - especially before trying ANY service menu adjustments. Many people have adjusted the wrong parameter to the wrong value and the set never worked again!Wink

http://elektrotanya.com/...egoria=&kat2=all

Remember they limit you to two downloads a day so it may take a couple of days to obtain.


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Location: Far, Far Away


HostileHST
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Aug 17, 2012, 1:34 AM

Post #3 of 4 (3620 views)
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HostileHST
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Nov 3, 2012, 6:18 PM

Post #4 of 4 (3436 views)
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