Toshiba 42H82 Convergence Problems


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Toshiba 42H82 Convergence Problems

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krankshaft
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Aug 10, 2005, 12:53 PM

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Toshiba 42H82 Convergence Problems	Can't Post

Yesterday I turn my Toshiba 42" Rear Projection TV on and the red convergence was off by about 2". It was like watching TV in 3D. Tried the touch focus automatic convergence and it said Touch Focus Error so then I tried adjusting red manually through both the user interface and the service mode to no avail.

The red will converge vertically but not horizontally. I would hate to have to replace the whole convergence board as the service manual suggests but will as a last resort.

When I got into service mode the red line is distorted at the bottom while the green and blue remains nice and straight.

What components on the current board would I need to replace to get the red to converge properly?

I have read 2 IC's STK392-110 should be replaced and the surrounding capacitors. Also I know these ICs are pretty large with heatsinks on them but are they located on the convergence board or the power board? I have read conflicting info on where they are and the service manual is useless for component troubleshooting.

Not sure if this applies to my specific model though.

Thanks for any help in advance.

(This post was edited by krankshaft on Aug 10, 2005, 2:29 PM)

mikemaiertv
Enthusiast

Aug 13, 2005, 6:16 PM

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Re: [krankshaft] Toshiba 42H82 Convergence Problems [In reply to]	Can't Post

Just replacing the two convergance Ic's will in most cases repair the set. Only in about 2% of the time do we find bad caps in the curcuit, so for a first timer just change the Ic's, And they will be monted on the signal board and they will be the only two with the STK392-110 printed on them
Mike Owens Lead tech Maier TV Spokane Wa

krankshaft
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Aug 14, 2005, 12:20 AM

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Re: [mikemaiertv] Toshiba 42H82 Convergence Problems [In reply to]	Can't Post

Thanks for the reply I just ordered the ICs Smile

.

Luckily I have Arctic Silver heatsink compund from when I replaced my computers heatsink so I can wipe off that probably inferior old stuff and use a good thermal compound which may extend the new STK's life.

Good thing to know that the STK is on the signal board and not on the same board with the flyback I'm assuming its on the power supply board discharging those things still makes me twitch Cool

. I made my tool out of an old microwave probe and attached an alligator clip on the end it kind of looks like Apples Discharge tool when they used to sell them.

(This post was edited by krankshaft on Aug 14, 2005, 12:21 AM)

TomP
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Aug 16, 2005, 1:22 PM

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Same exact problem on my Samsung 54". Auto convergence didnt fix the problem and manual Red convergence moved up and down but not sideways.

Been on different forumsa all morning. Read one about an hour and half ago that said to try unplugging the tv for at least an hour...did that and continued searching forums.

just plugged it back in and YES!!! manual red convergence now moving sideways and I was able to fully adjust it!!

The forum post that I read this on...not even sure (been on quite a few) also suggested that a power surge might have thrown it out of wack and to get the best surge protector you can find. Buying one this afternoon.

Hope this helps u 2.

TomP

krankshaft
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Aug 16, 2005, 4:03 PM

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Mine was already on a surge protector had it on one ever since I bought it and we did have a thunder storm the night this thing screwed up. Sadly I tried unplugging it already for one hour to no avail replaced the STK convergence IC's it actually made it worse then the green wouldn't converge vertically.

I ended up replacing the whole signal/convergence board for about $360.00 plus shipping got it at partstore.com my wallet is still in pain but at least I got this thing working again without a labor fee Smile

.

Here are instructions for removing this board wether you want to replace it or want to know how to get it out to replace the STK ICs.

First get the back cover off the tv (6 hex screws) now we will lift part of the chassis out so you aren't putting your screwdriver near the tube driver boards for safetys sake. You will notice there is a plastic frame screwed to the wood frame of the tv. There are 3 wood screws along the back bottom edge of the TV securing a plastic frame down loosen them. Now GENTLY pull the plastic frame which the boards are screwed on back and angle it out to the right the HV wires have plenty of slack for you to remove the signal board. If wires from the signal board are obstructing try pulling them out of their cable clamps to give you more slack.

You don't need to discharge the RED (high voltage wires) from the flyback and its relatively safe to work around them just don't go poking Mr. Screwdriver on them. Or touch any area of the biege power board the signal board is the green one on the right of the tv looking from the back. To disconnect the power from the signal board to the power board get a flat head screwdriver and you'll notice 3 connectors from the signal board to the power board and on the power board side you will see small flaps protruding from the connectors GENTLY pry them up with the screwdriver. Pull out all the connectors from the board if you wish take pictures of them or draw a diagram while they only plug in one place its pretty time consuming if you forget where they go Wink

.

Now loosen the screws from the board to the plastic frame and the support for AV board at the back (4 screws) then remove the little screws visible near the A/V Phono connectors once all of them are out pull the little plastic bezel off. Now if you wish pull up on the A/V board and it disconnect from the signal board. Now for removing the board itself don't pull straight up on the board or you'll break it pull it up from the power board side first then slide it to the left and pull it out. If the board doesn't come up check for screws DON'T FORCE or you may crack the board.

Replacing the board is very straight forward the connectors will only connect in one place so you can't screw them up. Also there were 2 vacant connections on my Toshiba 42H82 where no cables connected one on the metal shielded tuner board and another on the signal board.

The only thing you have to watch is the 3 plugs for the tubes my cables were marked from the factory the red connector had a red line on it same for the blue and the green had no mark because its the remaining cable. Just match them up to the printed Red, Green, and Blue on the board and you can't go wrong Cool

. But if you do all that will happen is your TV colors will be all funky Tongue

.

I'm still mad at this 2002 TV breaking this soon though especially because it doesn't get any heavy use Mad

.
Thanks For The Tip Though I'm Sure It Will Help Other People Wink

.

(This post was edited by krankshaft on Aug 16, 2005, 4:33 PM)

sreered
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Sep 24, 2005, 12:09 AM

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Thanks for all the info about replacing convergence IC's. My 4 year old Toshiba 50H81 suddenly failed coverging red after a power fluctuation. I already obtained two Sanyo STK292-110's from audiolabga.com and am out to replace them per instructions here. I think I can desolder and solder the IC's fine but my main problem is getting the signal board out.

So far I have removed the back cover, unscrewed the plastic frame, and tilted the plastic frame (on which the boards are screwed) to the right. Please see attachment 1. I am not sure how to detach the signal board from the power board per instructions here. Please see the red arrow in my attachment. Are those the connectors I should be disconnecting?. Am I risking a shock if I touch the red HV wires in that process?. I switched off the T.V for over a day but I just want to make sure. I also would like to know if I should disconnect any wires from signal board to be able to take the board out and solder the IC's.

The 2nd attachment shows how it all looks right now. This is how far I could tilt the board. Am I doing this right?.

Any help will be appreciated. Thanks!

(This post was edited by sreered on Sep 24, 2005, 12:13 AM)

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toshiba_50h81_1.jpg (134 KB)

toshiba_50h81_2.jpg (128 KB)

krankshaft
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Sep 24, 2005, 12:40 AM

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Re: [sreered] Toshiba 42H82 Convergence Problems [In reply to]	Can't Post

Yes you are doing it right you see those white power connectors take a screwdriver and you will notice a tab on the power board side use the screwdriver to pry those two white connectors up. Same for the little blue one. Then disconnect any connectors going to the signal board.

As for the HV wires don't worry as long as there are no cracks in the insulation even if you do touch them it won't do any harm.

Once you have all connectors on the signal board removed then remove the 2 AV board cables then loosen the rear AV board support screws (3) two on each side securing it to the plastic frame and one on the right behind the AV Card support. Then to loosen the AV card bezel remove the 6 or more screws around the Video Inputs and loosen the bolt around the center coaxial connector. Remove the AV board bezel and support now simply pull up to remove the AV card and put it in a safe place. Since it will wobble if you leave it in when you flip the board over for soldering.

Next remove all of the screws securing the signal board to the plastic frame including the ones that secure the power board and the signal board once all have been removed lift the board upward from the power supply side (left side) don't lift straight up or you will break the board since there is a lip on the right hand side of the frame. If the board doesn't lift up easily from the power board side you have forgotten screws don't use excessive force or you will crack the board (a $350.00 mistake for your information). Just keep that in mind when you are handling the board and you'll be fine Cool

.

Post back if you need more info Smile

.

Also I hope you tried unplugging the TV for a little while before attempting this you never know.

(This post was edited by krankshaft on Sep 24, 2005, 12:51 AM)

sreered
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Sep 24, 2005, 7:37 AM

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Thank you very much. I will give this a try Smile

krankshaft
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Sep 24, 2005, 2:06 PM

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Re: [sreered] Toshiba 42H82 Convergence Problems [In reply to]	Can't Post

Also don't forget use desoldering braid on the IC pins you also will need to desolder the 4 heat sink pegs as well you should buy a manual squeeze hand pump since they used alot of solder on the heat sink pegs once the heatsink and the IC pins are desoldered then you can simply pull up on the heatsink and the IC and the heatsink come up as one assembly then unscrew the IC from the heatsink.

Also be sure to remove the old thermal compound from the heatsink by wiping most of it and finishing it by rubbing the rest off with some rubbing alcohol. Then put new thermal compund on the back of the IC and the heatsink you can use ordinary heatsink thermal compound for CPUs this can be found at any computer store for about $10.00 and under. This stuff comes in a syringe so you simply squeeze a small bead on the heatsink and chip and smooth it over with a handheld straight razor knife.

Also after you replace the ICs your convergence will be off the first step is to try and use touch focus if that doesn't work post here and I'll let you know how to adjust it manually and don't try the user mode convergence it won't work you'll need to get into service mode convergence don't worry its an easy process to adjust alot easier then that useless dumb crosshair user convergence IMO. If necessary.

(This post was edited by krankshaft on Sep 24, 2005, 2:22 PM)

sreered
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Sep 25, 2005, 9:16 AM

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Thanks for all your help :). I got the signal board out yesterday. I will get to the soldering part today.

sreered
Novice

Sep 25, 2005, 9:46 PM

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I did everything right and put the new IC's in but the convergence problem is not solved Frown

. It's just like before. Red converges horizontally but not vertically. I mean I can move red left and right in all convergence modes including service mode but can not move it up and down. Red is bowed down from top and bowed up from bottom. I am not sure if I should be replacing any other capacitors or resistors surrounding the convergence chips. I think I should take the signal board to a local T.V service center and see if they can fix anything!. Any advice?.

If I must replace the part, is it "SIGNAL CONV Board,PD0073A" at partstore.com?. It is listed at $228. There is also a "DIGI-CONV Board,PD0078A" at $133 but not sure what that is!.

(This post was edited by sreered on Sep 25, 2005, 9:50 PM)

krankshaft
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Sep 26, 2005, 2:48 PM

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It could be one of the surrounding capacitors but since I have no schematics I can't tell you which one I'm sure if you take it to a T.V repair shop they will replace whats needed. I would say their first guess is always the convergence ICs so it would be best to tell them its not that.

As a final move try to ask your question on about.com and maybe they can tell you the exact component you need to replace. These people are experts in TV repair.

Go to this link and click ask question enter your question and you should get a reply by e-mail within a day.

http://allexperts.com/...ert.asp?Expert=13142

or

http://allexperts.com/...pert.asp?Expert=9867

If you want a second opinion.

At the worse case scenario 100% replacing the signal/convergence board will repair the TV however going that route you would also need to desolder some old parts from your old board though those 2 rf shielded boxes (tuner & pip module) you only have to desolder 4 points on each securing the the RF boxes to the board the cards themseleves just plug into a slot. Remove the 2 riser cards and the plastic clips holding them (SRS 3-D Module & the Dynamic Pincushion Card) (DPC). And finally desolder the coaxial cable connector plugs from the two tuner demodulators. The plugs look like ordinary A/V plugs soldered in place.

The digi conv board is the board for the touch focus your problem doesn't lie there its the singal conv board I wouldn't order from partstore.com unless your ready to wait since they mostly back order these from the factory. Try tritronicsinc.com if you need it since they will let you know if they have it in stock.

(This post was edited by krankshaft on Sep 26, 2005, 2:51 PM)

KKCT
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Oct 1, 2005, 9:57 AM

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Hi Krankshaft,

I am having a convergence issue with my Panasonic 53" Projection TV. Can you please help me on how to remove the power board from the signal board as I am planning to change the ICs. I am stuck here. I saw the picture posted by the other gentleman here. I couldn't really understand how you were telling to remove these 2 boards.There are 3 white color connectors from the power board to the signal baord. From what I understand these connectors are removable. My concern is how can we remove these. Whats the meaning of PRY? Can you please elaborate in detail how I can remove this? Also if you can tell me the part name for the convergence board in case I end up replacing the entire board..hence I wan't to keep it handy.Thanks in advance !!

Thanks,

KKCT.

sreered
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Oct 1, 2005, 11:33 AM

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KKCT, I can tell you about separating power connection from signal board. The three white connectors you see should have a small tab protruding on the left side (towards the power board). You have to carefully reach these connectors from the power board side and lift the connectors up using a flat head screwdriver. Make sure you don't poke the red wires. Position the flat head of the screwdriver under the connector tab and gently lift up the connector. It will open towards the signal board. Hope that helps.

BTW, you are not removing the white connectors. You are just lifting them up so they are disconnected from power board Smile

.

(This post was edited by sreered on Oct 1, 2005, 11:35 AM)

KKCT
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Oct 1, 2005, 1:13 PM

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Thanks Sreered....will follow your advice !! Hopefully it should work fine now. In case if I am having any problems, can I have your contact # so that I can reach you directly(only if you want to give ur # otherwise its fine). Also by the way what happened to your TV set? Did you end up replacing the entire convergence board? If yes can you pls mention me that part # as well as its name !!

Thanks much for your help !!

KKCT.

sreered
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Oct 1, 2005, 2:12 PM

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No, I have not replaced the whole signal board yet. I called couple local TV service centers and one of the guys agreed to look at the board and see if any other defective components need to be replaced. I gave the board to him today and he is going to get back tomorrow after checking. I am still hoping I don't need to replace the whole board. More than the price, I don't want to wait weeks since these parts are usually back ordered.

I will check this thread later so post here if you run into any problem.

To those looking for local TV service centers, I think the easiest way is go to superpages.com, enter "tv repair" in keyword and enter your location. You should find listings under "Televisions Service & Repair" category.

(This post was edited by sreered on Oct 1, 2005, 2:20 PM)

KKCT
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Oct 1, 2005, 2:20 PM

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Thanks Sreered !! Will try & keep u posted if I have any problems. By the way as I was unable to remove the signal board , I already ordered the ICs from electronix.com & replaced it with the old ones but the TV has gone even more worse now..Earlier there was a Blue line coming in the picture but now there is a hissing sound & when I switch off the TV, it goes off after some fireworks sort of thing !! Im really scared..hope I haven't messed up something else. One person told me that the ICs from elextronix r pretty cheap & they told me 2 try the ICs from audioblga.com. Hence I have ordered for the new ICs from there & hope to remove the board & do the soldering properly this time. Guess earlier there could have been a soldering issue..hence it didnt work. Do you have any suggestions??

Thanks,

KKCT.

sreered
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Oct 1, 2005, 3:59 PM

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Hmm, if you did not remove the signal board how did you solder the ICs?. Those pins are close to each other and the solder has to form a good connection without touching other pins.

KKCT
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Oct 1, 2005, 4:29 PM

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I just removed all the screws, all the connectors except the white ones which connects both the boards & then tilted both the boards together n did the soldering !! Smile

KKCT.

KKCT
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Oct 5, 2005, 3:38 PM

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Hi Sreered,

I am with my TV right now trying to remove the power board from the signal board. I am not able to disconnect the white connectors..Please help asap as Im off today..tommorow onwards I'll be @ work..hence I have time today to do or else will have 2 wait for 1 week. Im trying 2 insert the flat screwdriver under the tab but when I try to lif it up, I fear something will break. Is that the right way 2 do??Thanks again !!

KKCT.

sreered
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Oct 5, 2005, 8:22 PM

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Yes, that's right. With the flat tip of screwdriver just lift the connector up from the power board side. You need to use some force but gently. It's like moving the tip of the screwdriver up without moving your entire hand up. Try to keep your hand stationary and give an upward thrust to the tip of screwdriver.

KKCT
Novice

Oct 5, 2005, 10:06 PM

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Re: [sreered] Toshiba 42H82 Convergence Problems [In reply to]	Can't Post

Thanks for the reply Sreered..!!Thats exactly what I tried..Can you please check the picture I have attached here guess the tab is one with the black arrow..right..I put the screwdriver below the tab & tried 2 lift the connector upwards but looks like the tab was attached to the base..the tab like thing broke :-( & the connector is still intact. Not sure if I am doing the right thing. Can you please advise. If you can give me ur # or chat ID, that could be very helpful for me 2 solve the problem. My yahoo messenger ID is krishibm. Please HELP !!

Thanks,

KKCT.

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sreered
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Oct 5, 2005, 10:21 PM

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KKCT, yes the tab is the one with black arrow. See if you can lift the first white connector by inserting a finger under the gap. Approach from the signal board side and lift the connector with finger. Lift it so it opens towards the signal board side. I was able to do this on my Toshiba. But you should be able to easily do this with screwdriver. I am not sure how the tab broke. I hope it's not designed differently on Panasonic.

KKCT
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Oct 5, 2005, 11:59 PM

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Re: [sreered] Toshiba 42H82 Convergence Problems [In reply to]	Can't Post

Hi Sreered,

I am not able to lift the connector with the finger..looks like the tab is attatched & not removable. Also possible that this thing is designed differently for Panasonic. Can you suggest any other way how we can remove these connectors or any place from where I can know the details??

Thanks,

KKCT.

Guinry
New User

Oct 7, 2005, 9:41 PM

Post #25 of 66 (11609 views)
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Re: [sreered] Toshiba 42H82 Convergence Problems [In reply to]	Can't Post

Sreered,
I have a Toshiba 50H82 with the same convergence problem. I ordered the 2 STK392-110 IC's from audiolabga.com and installed them, but it didn't fix my problem either. I have checked a few random caps on the board with a meter, but haven't found any bad ones yet. I'm a little hesitant to spend $230 for a new board in case it doesn't fix my problem.
Any word from the tv repair shop about your board?

Thanks to everyone for the helpful info posted here, and any suggestions are much appreciated!

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