Rear projection TV STK 392-120 LG convergence problem

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Swapan Sutradhar
Swapan Sutradhar's picture
Hi,

Hi,
Could you please let me know which 3-channel audio power amplifier STK ICs have
package 4158 and dimensions 64mm x 31mm x 8.5mm.Wattage may be from 3x25W to 3x40W.
Regards,
Sutradhar.

Swapan Sutradhar
Swapan Sutradhar's picture
Hi,

Hi,
Could you please let me know which 3-channel audio power amplifier STK ICs have
package 4158 and dimensions 64mm x 31mm x 8.5mm and may be wattage from 3x25W
to 3x40W.
Regards,
Sutradhar.

Swapan Sutradhar
Swapan Sutradhar's picture
Hi,

Hi,
Could you please let me know which 3-channel audio power amplifier STK ICs have
package 4158 and dimensions 64mm x 31mm x 8.5mm and may be wattage from 3x25W
to 3x40W.
Regards,
Sutradhar.

daveh56
daveh56's picture
ALWAYS replace convergence

ALWAYS replace convergence ICs as a set. Use the stk392-120 only in this set make sure the IC's are genuine Sanyo IC's otherwise you will have problems.

Dave

Vick
Vick's picture
Hello also had convergence

Hello also had convergence problem bought 1 of the IC 'but could not get all the colors aligned.Bought a nother 1 and get it almost perfect.When align the colors
green and red align well but blue.Difference in Ic is that it dont have the same batch number could that effect it.
Thanks in advance
regards
Vick

Vick
Vick's picture
Hello DJ I did check all the

Hello DJ I did check all the resistors everything check ok.Get the picture very reasonable to the bottom and middle of screen.(to me it seems o.k , customer don't like the idea that it is not exactly right)The top is out(blue) when trying to align the top then it get messed up at the bottom.Maybe could be like Dave said about buying the I.C as a pair?
Thanks for the help!
regards
Vick

Sipheren
Sipheren's picture
Hi,

Hi,
I have the same LG rear projection TV RT-39NZ43RB, I replaced the IC's using the posts here, thanks :). When I turned the set on after replacing the IC's nothing changed so I pulled out the convergence board again and I am going to replace the resistors as well, will this most likely be the problem?

(The red and blue seem to be the colours that are out on my set)

Thanks

Sipheren
Sipheren's picture
I just checked over all the

I just checked over all the resisters, they are all fine so I didnt need to replace them. The image is still not correct but, it seems only the red is out. What should I do next?

Sipheren
Sipheren's picture
I checked the resistors with

I checked the resistors with one leg out, they all seem to read the correct ohms. I also checke the IC solders. All seems good, everything plugged in. Haven't checked the lenses, how do I do that?

I think I may have to do a manual convergence instead of using the auto one, hopefully that will work.

Sipheren
Sipheren's picture
So I am trying to do the

So I am trying to do the manual converge on the TV, this is what it looks like but I cant seem to make it adjust enough to be correct, the red is really out.


Sipheren
Sipheren's picture
It seems the red doesn't seem

It seems the red doesn't seem to adjust very much, the other colours move quite a lot but the red only can move a little. The ic's are new and the resistors are still ok. Any ideas?

Johan Coetzer
Johan Coetzer's picture
How do you get in service

How do you get in service menu please ...................

Sipheren
Sipheren's picture
You press the menu button the

You press the menu button the remote and TV at the same time.

Cheers

daveh56
daveh56's picture
Is the red convergence IC

Is the red convergence IC overheating or is it running cool? If it is running hot you might have a SHORTED resistor. To check them unplug convergence windings plugs first (tv unplugged of course!). If any resistor reads less then 1 ohm it is bad. It could be the convergence control unit is bad. If that is the case GET a NEW TV unless you plan on spending hours and hours and hours and hours adjusting the new convergence unit. Good Luck!

Sipheren
Sipheren's picture
How do I know which ic is the

How do I know which ic is the red one? I replaced boththe ic's, they both are hot when the tv is on but I thought that is normal....

Larry Dillon
Larry Dillon's picture
that is normal maybe you got

that is normal maybe you got a bad ic?? where did you get the ic's from?? you could switch around the ic's to see if the screen problem changes to another color.
Larry D

Sipheren
Sipheren's picture
That's a good idea, will try

That's a good idea, will try it. I got the ic's from the place in Canada in this thread.

Cheers

Larry Dillon
Larry Dillon's picture
tv repairkits.com will ship

tv repairkits.com will ship out to Canada that way you know for sure you are getting original Sanyo ic's

redsock
redsock's picture
Hat's off to everyone here. I

Hat's off to everyone here. I registered specifically to give y'all kudos.

I have an LG RT44 that kakked itself recently. Thanks to reading this thread specifically, fixing it up was a snap.

The STK392-120s weren't difficult to replace, and mine definitely took out two resistors with it. Interesting, I am not 100% confident that the STK392-120 actually died, but replaced them anyway.

In case anyone else was interested in the various resistors that hover around the STK392-120, they seem to be different depending on manufacturer/date/etc.

My board in total has the following metal film resistors:
Qty 9 5.6 ohm 2 watt 5%
Qty 12 220 ohm 2 watt 5%
Qty 6 3.9 ohm 2 watt 5%

and I can say that the lack of auto convergence on this particular model really sucks, doing it by hand after the fact was not my idea of a good time.

My local repair shop here in Australia quoted me $550 to replace it, all up I am into it for $35 and a few hours of my life.

Thanks again for all your invaluable input. Made my life a lot easier and saved me a heap of screwing around unnecessarily.

Cheers!

Larry Dillon
Larry Dillon's picture
redsock, glad to hear you

redsock, glad to hear you decided to tackle this repair yourself one question though the stk chips you replaced them with are you sure that they are the original chips and not the china made or rejects as if you did not buy originals and you cannot buy originals for lets say 35 bucks a set .you must have had a dog of a time adjusting your convergence and through the months as they heat up will drift the adjustment a little at a time till you eventually will not be able to get the lines where you want them. good luck glad to hear you had a successful repair!!!!
Larry Dillon

redsock
redsock's picture
Hey Larry, ha! Well, I bought

Hey Larry, ha! Well, I bought them from richtechparts for $10.90 ea. They claim(ed) that they were Sanyo original parts, and they certainly looked like the real deal when I got them. So that plus shipping and about $3.50 worth of resistors and I was set.

Given that the STK392-120 puts out so much heat, I am surprised that there is not visible damage and/or heat damage to the one that apparently went bad. (Sorta like you'd expect to see after burning up an audio amplifier transistor). Its the reason I said in my post I wasn't entirely sure whether the STK392 actually went bad or not.

In hindsight I would have probably opted to just replace the resistors and see if that actually fixed it, but hey, it is working :-)

So what you are saying is that if the ICs I replaced are dodgy/lame ones that it is only a small amount of time before I get to do the whole exercise again?

Cheers

Larry Dillon
Larry Dillon's picture
highly unlikely they are

highly unlikely they are original chips for 25 bucks those chips cost almost that much for one!!!!!!
Larry D

Sipheren
Sipheren's picture
Got mine to work, I somehow

Got mine to work, I somehow missed to 2 resister on the board, they happen to be the two that are for the red colour.

I just need to manually converge everything, is there a special way to do this, like a template or something?

dayawansha
dayawansha's picture
Sipheren said:

Sipheren said:
Got mine to work, I somehow missed to 2 resister on the board, they happen to be the two that are for the red colour.
I just need to manually converge everything, is there a special way to do this, like a template or something?

hi,,hows ur red colour problm,,is it Ok now..

ello1828
ello1828's picture
Hi I started the thread two

Hi I started the thread two years back and kept myself in touch with all the posting all the time.

I am back to write as my LG time started convergence problem again. It started because I dragged it on the floor for around few meters.
I have changed both STK ICs. but convergence problem hasn't been fixed.

all three colours are out. picture is same even with our without convergence board plugged.
seems it is not even reading convergence board. I looked around no other ic is burnt or solding cracked.

Any ideas.

Thanks for your help in advance.

dayawansha
dayawansha's picture
gtexaust said:

gtexaust said:
Hi I started the thread two years back and kept myself in touch with all the posting all the time.
I am back to write as my LG time started convergence problem again. It started because I dragged it on the floor for around few meters.
I have changed both STK ICs. but convergence problem hasn't been fixed.
all three colours are out. picture is same even with our without convergence board plugged.
seems it is not even reading convergence board. I looked around no other ic is burnt or solding cracked.
Any ideas.
Thanks for your help in advance.

hi...,,,,gte whats ur  tv model...

dayawansha
dayawansha's picture
gtexaust said:

gtexaust said:
TV RT-39NZ43RB here it is. thanks

gte..,with the picture go to picture MENU & go to convergence adjustment means to get the CROSS in the middle of the screen....,,,,just check this CROSS coming or not....,,,,,in this model there is two types of CROSSES coming.....,,,,1 is .....,,,,1 CROSS & the other 1 is  CROSSE....,,,,,try whether theses both types of CROSSES coming...

dayawansha
dayawansha's picture
dayawansha said:

dayawansha said:

gtexaust said: TV RT-39NZ43RB here it is. thanks

gte..,with the picture go to picture MENU & go to convergence adjustment means to get the CROSS in the middle of the screen....,,,,just check this CROSS coming or not....,,,,,in this model there is two types of CROSSES coming.....,,,,1 is .....,,,,1 CROSS & the other 1 is  CROSSE....,,,,,try whether theses both types of CROSSES coming...

sorry some spelling error..........what i meant 1st is 1 CROSS & the other 1 is 9 CROSSES....,,,,just check whether these crosses are appearing when you go through Picture Menu to adjust the convergence......Surprised

redsock
redsock's picture
gte's post said that the

gte's post said that the picture doesn't change even with the convergence board completely unplugged. Sounds like a power-supply related issue to the circuit itself, yah?

If moving it is what caused it to go, I'd be checking supply voltages to see where it has failed.

ello1828
ello1828's picture
no in this model no cross.

no in this model no cross. from MENU it has Auto Convergence which I ran few times.
I checked power supply, it is ok. I do get picture which is completely distorted with all three colours all over the place.

Is there any way to ensure convergence board hasn't got any problem ?

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