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Crumbtrail TV Forums: TV Equipment: Projection TV Forum:
RCA R52WH74 convergence question

 

 


Tenn_pin
New User

Mar 21, 2010, 2:24 PM

Post #1 of 17 (12093 views)
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RCA R52WH74 convergence question Can't Post

I have an RCA R52WH74 with a convergence problem. I looked on eBay and matched the reported board and removed the board. Which parts usually fail on the convergence board? Is there a free schematic that can be DL off the internet? I have not been able to locate a rebuild kit for this board. Is the fuse (FL231) that usually goes bad on this board, or on the power supply board? I am a 30 year Pinball hobbiest and now am trying to tackle the repair on my son's TV. Thanks for any help.

Tenn_pin at yahoo dot com



Ron.M
Veteran


Mar 21, 2010, 11:10 PM

Post #2 of 17 (12081 views)
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Re: [Tenn_pin] RCA R52WH74 convergence question [In reply to] Can't Post

Tenn_pin;....

Before you go & blow a bunch of moola on a "new" board or trying to get your board rebuilt , how about you TRY to fix the one you have ?????
Since you seem to have some experience , it shouldn't be that big a deal....
You just need some basic electronics knowledge & soldering skills....
When you say "Pinball hobbiest" , does that mean you play the machines a lot or clean relay contacts etc ????
A "Service Manual" for the ITC222 chassis (Yours) is available online....
However , it's a generic & NOT model specific....

Chances are that the problem is NOT on the "convergence" board.....
You'd have wasted some money & been surprised when you installed the "new" board & it did NOT fix the TV....
IF in the pix below shows the fuse & location of it as correct , then replace the fuse (FL231) with a one half amp pica fuse & RESOLDER ALL THE CONNECTIONS ON THE FLYBACK !!!!



The flyback is the big black thing with the heavy red wire coming from the top , on the left side of the pix...
Turn the TV OFF & let it set for a few hours (Overnight would be best) to allow the higher voltages to discharge BEFORE you start the resoldering.....


GOOD LUCK.....


Later...Ron.M....Cool.....
Veteran & Retired TV technician


Tenn_pin
New User

Mar 22, 2010, 1:58 AM

Post #3 of 17 (12074 views)
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Re: [Ron.M] RCA R52WH74 convergence question [In reply to] Can't Post

I have cleaned many a EM contact and repaired many SS boards in the pins. I also picked up various video games and have done over 100 cap kits on monitors.
I will pick up a fuse tomorrow and replace it. I will also reflow the solder joints on the flyback. The set has not been on for 2 weeks, so the FB should be drained, but I will discharge it prior to attempting to repair.

Thanks for the reply...
R


Ron.M
Veteran


Mar 22, 2010, 2:36 AM

Post #4 of 17 (12070 views)
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Re: [Tenn_pin] RCA R52WH74 convergence question [In reply to] Can't Post

Tenn_pin;....
Thanks for the speedy reply....Laugh.....

Since you clarified your experience (Thanks) , you should have NO trouble doing this repair....Smile...
Also , since the set has been off for 2 weeks , there's really
no need to discharge anything...
But you may want to for your own peace of mind....Angelic...

GOOD LUCK.....

PLEASE post back with the results.....Sly.....


Later...Ron.M.....Cool.....
Veteran & Retired TV technician


Tenn_pin
New User

Mar 28, 2010, 6:38 PM

Post #5 of 17 (12049 views)
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Re: [Ron.M] RCA R52WH74 convergence question [In reply to] Can't Post

I checked the FL231 and it was blown. I had to order a replacement and installed it this morning. Now the set has vertival collapse. I have worked on arcade monitor cassis before. The vertical and horizonal drive line is marked on most boards, but I did not see any such markings on the board. Is the vertical drive on the power supply board? I am sure I knocked something loose, but would like to know where to start. I hate to try and fix something that is not broken, which is why I want to concentrate on only the vertical section.

Thanks,
R


Ron.M
Veteran


Mar 28, 2010, 6:54 PM

Post #6 of 17 (12048 views)
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Re: [Tenn_pin] RCA R52WH74 convergence question [In reply to] Can't Post

Tenn_pin;....

Recheck ALL connectors....EVERY single one....
Look for bent pins , pins pushed thru the board , etc....
Make sure they are in their correct location...
Make sure they are firmly seated....
Since you did not have this problem to begin with , something happened while you replaced the fuse....
Double check the re-soldered flyback connections for a "solder short" between a couple of the pins....

Let me know what you find....


GOOD LUCK.....



Later...Ron.M.....Cool....
Veteran & Retired TV technician


Tenn_pin
New User

Mar 28, 2010, 7:12 PM

Post #7 of 17 (12046 views)
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Re: [Ron.M] RCA R52WH74 convergence question [In reply to] Can't Post

I did not resolder the FB, but I did look at the solder joints under a magnafying glass and they looked OK, so I did not try to "FIX" it.
I did recheck all ribbons and connectors. There was a lot of josiling of the board to get it out, so I may have caused a cold solder joint that way. The arcade world has free schematics everywhere. Is there a place that has a free schematic for this set? I am a cheap ass bastard and hate to spend money on something I will use 1 time.

Thanks,
R


Ron.M
Veteran


Mar 28, 2010, 9:05 PM

Post #8 of 17 (12044 views)
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Re: [Tenn_pin] RCA R52WH74 convergence question [In reply to] Can't Post

Tenn_pin;....

IF you are NOT going to follow my advice , what's the sense of me giving it ????....Mad...
Bad connections are NOT always visable !!!!....
Re-solder the damn flyback...PERIOD !!!!...
Not only are you;=>..."""I am a cheap ass bastard""" , but one that doesn't listen very well....



Later....Ron.M.....Cool.....
Veteran & Retired TV technician


Tenn_pin
New User

Mar 28, 2010, 10:52 PM

Post #9 of 17 (12041 views)
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Re: [Ron.M] RCA R52WH74 convergence question [In reply to] Can't Post

Sorry, did not mean to offend. It is a time issue. Besides, there was no verticle collapse prior to the fuse repair. This is a learning project for me. Sorry to bother you and thanks for the input.

R


Ron.M
Veteran


Mar 29, 2010, 12:12 AM

Post #10 of 17 (12037 views)
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Re: [Tenn_pin] RCA R52WH74 convergence question [In reply to] Can't Post

Tenn_pin;....

"""It is a time issue."""
I have NO idea what that means....
If you are talking about rushing a repair on a TV , a lot of times that's NOT a good idea....PATIENCE , sir , Patience pays off ....


"""Besides, there was no verticle collapse prior to the fuse repair."""
This is what I said in post #6;=>...""""Since you did not have this problem to begin with , something happened while you replaced the fuse"""....
I was reffering to the loss of vertical sweep....(BTW:...You can NOT repair a fuse , you replace them..)...

FL231 provides B+ to the vertical output IC ,etc , via the Flyback....
IF you blew the new fuse because you failed to re-solder the FB pins then you could have done further damage....Pirate....
OR "maybe" you just got lucky & blew ONLY the new fuse....
CHECK FUSE !!!!
IF you do NOT re-solder the Flyback , I'm done with you....Frown.....
So make the time....
Those pins are NOTORIOUS for causing the problem you have....Shocked.....

I have the manual & for now , that's all you need to know....Wink....

BTW:=>....
You did NOT bother nor offend me....
Pissed me off a little , maybe....Unsure....
But , I'm I'm a big boy & can handle it.....Angelic....
So it's your call....Solder the Flyback & we'll move on....

"""""This is a learning project for me."""
Then listen & we both will do fine....OK ????....

GOOD LUCK....

Later...Ron.M.....Cool....
Veteran & Retired TV technician


HostileHST
New User

Aug 15, 2012, 5:39 PM

Post #11 of 17 (8277 views)
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Re: [Ron.M] RCA R52WH74 convergence question [In reply to] Can't Post

Initially I had a very slight bend in the screen with color separation (3D affect, but only after it would warm up), so I did the fly-back trick and checked the FL231 fuse (was and is good, even took it out once to test, just to be sure) and it corrected the problem, but then I decided to touch up the long thin board the main AC power goes to and now the screen is so far out of joint and the convergence no longer works, even though it still shows up in the menu and attempts to converge, but stops right away. Again, I've done the fly back, checked fuse/s, re-soldered 3 boards including the fly-back board, power supply board to the convergence amplifiers (this is not the dual IC kind, but has a long string of transistors/mosfets) and the previously mentioned board that the main AC power goes into before it gets distributed to the fly-back and so on boards. I get about 156 volts to all boards mentioned yet on the power supply board for the convergence amplifier board, there isn't one proper voltage coming out at the +15, +53 sections. Instead it shows 13v on the +15 output and 2 volts on the +53 output. I am curious, if the board is getting the ON signal to the power supply boards or simply have some output caps that have gone bad. BTW, I re-solder the flyback twice and have checked the fuse at least 4 times. When I say re-soldered, I used solder wick to remove the old non lead solder then used 60-40 as it's replacement solder. Oh, before all this happened, the menu screen looked fine, convergence worked fine, just would separate the colors until it went into that 3D affect after about an hour or so, but it never really did bend anything like it is now. How would re-soldering one board, and checking all connections possibly cause an otherwise, "ok" tv to go bad. UGG.


jts1957
Veteran


Aug 16, 2012, 12:28 AM

Post #12 of 17 (8268 views)
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Re: [HostileHST] RCA R52WH74 convergence question [In reply to] Can't Post

WTF!

Either change your user name back or start your own thread! Mad


-------------------------
Location: Far, Far Away


HostileHST
New User

Aug 16, 2012, 1:40 AM

Post #13 of 17 (8264 views)
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Re: [jts1957] RCA R52WH74 convergence question [In reply to] Can't Post

I only have one user name and posted under this this thread cause it applies to the same model TV I have. If I had posted a new thread using the same model number, I can only imagine I would be told there is already a thread for that model, thus, why I posted in this one to avoid any issues with admins.


jts1957
Veteran


Aug 16, 2012, 2:01 AM

Post #14 of 17 (8260 views)
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Re: [HostileHST] RCA R52WH74 convergence question [In reply to] Can't Post


In Reply To
Initially I had a very slight bend in the screen with color separation (3D affect, but only after it would warm up), so I did the fly-back trick and checked the FL231 fuse (was and is good, even took it out once to test, just to be sure) and it corrected the problem, but then I decided to touch up the long thin board the main AC power goes to and now the screen is so far out of joint and the convergence no longer works, even though it still shows up in the menu and attempts to converge, but stops right away. Again, I've done the fly back, checked fuse/s, re-soldered 3 boards including the fly-back board, power supply board to the convergence amplifiers (this is not the dual IC kind, but has a long string of transistors/mosfets) and the previously mentioned board that the main AC power goes into before it gets distributed to the fly-back and so on boards. I get about 156 volts to all boards mentioned yet on the power supply board for the convergence amplifier board, there isn't one proper voltage coming out at the +15, +53 sections. Instead it shows 13v on the +15 output and 2 volts on the +53 output. I am curious, if the board is getting the ON signal to the power supply boards or simply have some output caps that have gone bad. BTW, I re-solder the flyback twice and have checked the fuse at least 4 times. When I say re-soldered, I used solder wick to remove the old non lead solder then used 60-40 as it's replacement solder. Oh, before all this happened, the menu screen looked fine, convergence worked fine, just would separate the colors until it went into that 3D affect after about an hour or so, but it never really did bend anything like it is now. How would re-soldering one board, and checking all connections possibly cause an otherwise, "ok" tv to go bad. UGG.


The only model number I see is in the subject line. (Re: [Ron.M] RCA R52WH74 convergence question).
Do you know how many different model numbers RCA used this chassis in?

You HAD a similar base symptom, but rest of current problems (after fuse & resoldering flyback) are your own doing. Which answers you own statement (Questions usually have a "?" - not a ".").

Quote
How would re-soldering one board, and checking all connections possibly cause an otherwise, "ok" tv to go bad.



-------------------------
Location: Far, Far Away


HostileHST
New User

Aug 16, 2012, 2:51 AM

Post #15 of 17 (8256 views)
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Re: [jts1957] RCA R52WH74 convergence question [In reply to] Can't Post

What would you have me do? I posted in the only place with this model in these forums.

The question/s is obvious, I needed to know what might cause the board to not put out +15 and +53 volts. Is the input voltage to high, the 156 volts that is? Could it not be getting the PS/ON signal, if not, what could cause that? Could a too low or too high B+ cause a shut down on the board that supplies power to the convergence amplifiers?


The questions are there, I simply didn't use question marks, don't fret my friend, I will help too when I can.


jts1957
Veteran


Aug 16, 2012, 3:24 AM

Post #16 of 17 (8251 views)
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Re: [HostileHST] RCA R52WH74 convergence question [In reply to] Can't Post

Once you select "TV Forums: TV Equipment: Projection TV Forum:," at the right side there is a "Post New" button to start a new post. Unimpressed

There also is a "Search Posts" button along the top of each page. Putting "R52WH74" in Search String blank produces 4 pages of results. Wink


-------------------------
Location: Far, Far Away


HostileHST
New User

Aug 16, 2012, 3:33 PM

Post #17 of 17 (8246 views)
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Re: [jts1957] RCA R52WH74 convergence question [In reply to] Can't Post

Thank you jts1957, for whatever reason, when I did my search prior to posting, I kept getting 0 results, was frustrating at the time, but glad to see it was user error, I can except that. Again thank you for pointing me in the right direction and I apologize for posting in the incorrect place.

 
 
 


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