[gbanco]

Hello all, this is my first post, and I hope that I can find some advice. I have a Toshiba 57H81, and it has a convergence issue. I'm no expert, but after surfing around the internet today, the problem seems to be consistent with bad convergence ICs.

This TV has the STK392-110 ICs. I see that some people recommend upgrading to STK392-150 or STK392-180, or (including a reference on this forum for another 57H81) the STK394-160 (although this seems to be for a different current requirement?). Does anyone have sound advice as to whether or not I should "upgrade" if I'm going to be replacing them, and to which version? I saw one post on a different forum that states that the resistors need to be replaced with lower ohm resistors if upgrading. Any advice on all of this?

Also, if anyone has the service manual for this TV, I would be grateful if you could send it my way. You could email it to me at my user name at gmail.

Any other tips anyone else has are very greatly appreciated!

Thanks in advance!

 

[gbanco]

anyone? :sad:

 

[lcaillo]

Sorry about the delay in response. I am at camp with scouts and working from my phone...
I have used the 394-160 in these sets but have heard off others that have had problems with that sub. There may be a difference in the muting cicuit that some have speculated or there
may be some counterfeit chips in the market. For those reasons I do not recommend subbing unless you are willing to take chances and are sure that the ICs are the problem. Many have become confused with problems like bad solder joints, fuses, or dcu problems. It is best to not introduce more variables.

Be sure to read the convergence repair sticky very carefully.
Posted via Mobile Device

 

[Loki2012]

gbanco,

I would like to know the results of your repairs. Did you use the original IC's, upgraded, or ??

 

[gbanco]

Loki2012,

Sorry for the late reply... None of my resistors, or other parts seemed to be bad, so I just went ahead and replaced the ICs with the originals (STK392-110) and left everything else alone. It worked like a charm, and the TV has worked fine ever since - knock on wood. Hope that helps.

 

[gbanco]

And thank you lcaillo, and this forum for your guidance...

 

[Eugene]

Hi gbanco,
This is the first time that I hear of advice to replace convergence ICs. Where did you find that level of advice on the internet? Unless you are a TV repair tech, I would shy away from this journey. Usually service manuals will take you through a circuit board adjustment, voltage check, waveform adjust procedure. I would suggest that it would be the exception to beleive that a straight substitution of ICs would do the trick. For me the unknowns outweight the benefits. I would stand down. And sleep at night!!!

 

[gbanco]

My problem occurred back in July 2009. I'm sorry, but I honestly don't remember the exact troubleshooting process I went through or specifically where I got the information that I thought it was a convergence IC problem...

I just looked around for a couple of hours, comparing the look of my problem with the look and description of other pictures posted on various sites. I guess I figured that for the $20 bucks I paid for the replacement ICs (ebay), and the couple of hours it would take to replace them, it was worth a shot...

I'm certainly not an expert, or a TV repair tech - just someone with a fair amount of general technical ability who was looking for a cheap fix... Maybe I just got lucky, but just replacing the convergence ICs with new, original type ICs worked perfectly...

So maybe Loki2012 (if he hasn't proceeded already with the IC replacement) should take cyberian's advice and not proceed without testing the other possible problems... But I'll take my luck and continue to watch my working TV. 8)

 

[lcaillo]

Hi gbanco,
This is the first time that I hear of advice to replace convergence ICs. Where did you find that level of advice on the internet? Unless you are a TV repair tech, I would shy away from this journey. Usually service manuals will take you through a circuit board adjustment, voltage check, waveform adjust procedure. I would suggest that it would be the exception to beleive that a straight substitution of ICs would do the trick. For me the unknowns outweight the benefits. I would stand down. And sleep at night!!!

He seems to have solved his problem, Eugene.

In fact, most manuals do NOT take you through specific checks and adjustments on convergence problems and many repair techs do not do much more than change the ICs to see if it works, and don't bother to do any significant adjustment once the do. The reason that many people DIY these, as I note in the very detailed sticky here at HTS, is that the level of service that they get from many a "TV Repair Tech" for the amount charged is far less than what one can DIY with a little homework.

Your suggestion proves to be incorrect information, as the vast majority of repairs of this nature ARE just changing the ICs, followed by some tweaking that most techs don't bother to do to get the most performance out of the set. There are some caveats, and I go to great length to discuss the matter here if you would like to learn something about the matter:

http://www.hometheatershack.com/for.../5600-crt-based-rptv-convergence-repairs.html

 

[Eugene]

Leonard,

Pardon my unfamiliarity with the HTS forum. I was looking for the stickys but was not able to find the one you referenced. I was not aware that we had DIYers who had the experience to try this and the TV Techs such as yourself who would share that knowledge with the forum. Cudos to you for writing the procedure and someone actually repairing their set on your direction. I definitely was not challenging you. I was not aware of your post. I was just erring on the side of caution.
A while ago I spent many emails on another forum trying to learn what I could offer a client who had a fuzzy picture on a Mitsubishi DLP RPTV WD82837. SteveH finally recommended that I should not attempt any tweaks at the customers site. It was a forum you once recommended to me. I am not a DIYer in this area. So I was OK with not attempting any adjustments after wading thru the service manual.
Thanks for brining this to my attention.

 

[Loki2012]

I was working on my brothers Toshiba 42H81 tv, took the board out and back home (I live an hour away). Since then my brother bought a new TV, and I have picked up the old one and put it in storage. Over the next few weeks, when I have time, I will do the repairs and post the results. Thanks everyone for posting their experience!

 

[ssteelma]

Thank you very much for the info on this site that allowed me to replace my convergence chips last week. I do have some specifics that took time for me to figure out that may save time for the next to try:

1. Removing the circuit card containing the heatsink/convergence chip assembly got to complicated. I finally removed the screws around the outside fixture/frame and was able to move the chassis as an assembly for access to solder joints on the bottom..
2. Even with the tiniest 90 degree screwdriver ratchet thingey from Sears I still had to remove the shielding from the assembly facing the chips to have any chance at accessing the heatsink screws. Apparently most of it is soldered to the circuit card. The side facing the chips does pop off but I did a bad job figuring it out and had to kludge it back together. Not exceptionally sturdy but works. Took several hours undoing/installing the component/reinstalling the screws.
3. One tube of thermal grease from the Shack was plenty. I bought 2. Also bought solder braid for solder removal.
4. Convergence chip leads on the closest component were fairly easily cut. I had to use a long standard screwdriver and small hammer to shear the other component's leads at the component body. The leads are long enough that there was no damage to the through holes.. Solder braid removed most all solder and cut leads fell out (hopefully not to cause another problem).

Thanks again,
Scott