Rear projection TV STK 392-120 LG convergence problem

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gtexaust
gtexaust's picture
Rear projection TV STK 392-120 LG convergence problem

 have LG rear projection TV RT-39NZ43RB. I had convergence problem six months back & I replaced one OF STK 392-120 IC. which fixed the problem. That time blue colour was out.

Now seems problem is back with green and light purple colour out.

Should I replace both STK ICs this time or the one which I didn't replace last time ?

To avoid same problem occuring again should I also go for STK 392-150 or may by STK 392-180 ?

Also I already have STK IC 392-120 bought from BIC  www.bluestar-online.com, is this right one to replace ?

Larry Dillon
Larry Dillon's picture
You should always replace

You should always replace BOTH convergence IC's at once unless you want to have to go into the TV set again within a few months or so. Blue-star as I understand it, is not the best place to purchase these convergence IC's from. They are very inexpensive at blue-star but that is part of the problem. I always buy mine from http://www.electronic-repair-kits.com/index.html Also, before you install the new IC's, install thermal paste to the backs of the new IC's. Good Luck

ello1828
ello1828's picture
Can you please also give me

Can you please also give me an idea how long Lamps of this TV can last and the

cost of a Lamp for this TV (LG RT-39NZ43RB).
and the best place to buy it from.

Thanks for your help.

ALOVRU
ALOVRU's picture
Larry Dillon said: You should

Larry Dillon said: You should always replace BOTH convergence IC's at once unless you want to have to go into the TV set again within a few months or so. Blue-star as I understand it, is not the best place to purchase these convergence IC's from. They are very inexpensive at blue-star but that is part of the problem. I always buy mine from http://www.electronic-repair-kits.com/index.html Also, before you install the new IC's, install thermal paste to the backs of the new IC's. Good Luck

hi, i also have an lg RT-39NZ43RB tv with a convergence problem. i have ordered the new IC's from www.electronic-repair-kits.com they did not have the STK392-120 in stock so i ordered the STK392-180 instead. will they be compatible? and is it possible for the all the resistors behind the IC to fail? because i tested them and all the 220 OHM 2 W are showing 110 OHM and all of the 3.9 OHM 2 W are showing 2.1 OHM on the multimeter.

thanks.

Dwray
Dwray's picture
The STK392-150 or STK392-180

The STK392-150 or STK392-180 are no better then the STK392-110 the STK392-120 is better BUT if you Want the VERY Best IC use the STK394-160

The STK394-160 is the NEW STK that Replaces the OLD STK392-110,120,150,180 IC'S The STK394-160 Runs MUCH Cooler !

ALOVRU
ALOVRU's picture
Dwray said:

Dwray said:
The STK392-150 or STK392-180 are no better then the STK392-110 the STK392-120 is better BUT if you Want the VERY Best IC use the STK394-160
The STK394-160 is the NEW STK that Replaces the OLD STK392-110,120,150,180 IC'S The STK394-160 Runs MUCH Cooler !

Thanks i have ordered the STK392-120, i would realy like to use the STK394-160 but i have not heard of anyone using them with the LG's yet. (don't want to make things worse) dumb question but do the convegence boards run AC or DC? i'm thingking of putting a pair of 12v DC fans to keep things a bit cooler.

Larry Dillon
Larry Dillon's picture
unless your an engineer and

unless your an engineer and have ran test on these circuits using these IC's would not recommend using these IC's as these sets go through united laboratories rigorous testing using the original IC"s that the manufacture recommends. and changing or modifying a circuit could also void your homeowners insurance, in case there was an fire or something like that yes I Have certainly used different unauthorized parts in a set in the past but I do not make it a habit nor would I recommend someone to do so as well.

Dwray
Dwray's picture
yes most everyone is still

yes most everyone is still using the STK392-110,120,150,180 because you can still find them Sanyo Stoped Making them about 1 year ago and NOW makes the STK394-160 some MFG. has updated there parts info Like Hitachi If you look up the Hitachi Set's that came with the Stk392-110 IC's They now show to use Part# CZ01341 which is the STK394-160 The STK394-160 is what will be replacing the 110,120,150,180 when they are all sold out of the surplus stock that sanyo has on hand now .

The Original Hitachi Stk392-110 was CZ00431 then It was updated to CZ00433 which was a STK392-150 and it was updated to the CZ01341 = Stk394-160

Forgot to add The NEW STK394-160 are $38 EA is another reason why most are not using them .

Dwray
Dwray's picture
ALOVRU said:

ALOVRU said:

Dwray said: The STK392-150 or STK392-180 are no better then the STK392-110 the STK392-120 is better BUT if you Want the VERY Best IC use the STK394-160 The STK394-160 is the NEW STK that Replaces the OLD STK392-110,120,150,180 IC'S The STK394-160 Runs MUCH Cooler !

Thanks i have ordered the STK392-120, i would realy like to use the STK394-160 but i have not heard of anyone using them with the LG's yet. (don't want to make things worse) dumb question but do the convegence boards run AC or DC? i'm thingking of putting a pair of 12v DC fans to keep things a bit cooler.

That would be DC Voltage

Dwray
Dwray's picture
STK392-110 is rated 3amp

STK392-110 is rated 3amp
STK392-120 is rated 4amp
STK392-150 is rated 3amp
STK392-180 is rated 3amp

The higher the Amp rating The Cooler the IC will Run and last longer

easyab
easyab's picture
Dwray said:

Dwray said:
STK392-110 is rated 3amp
STK392-120 is rated 4amp
STK392-150 is rated 3amp
STK392-180 is rated 3amp
The higher the Amp rating The Cooler the IC will Run and last longer

I believe the above statement is misleading and could be costly.  It is not the same as a higher rated fuse or a brighter lightbulb.

The various IC's have different specs, one important one is the quiescent current. The higher number STKs have a higher quiescent current (+10%) If you replace a STK 392-110 with an STK 392-150 the small value resistors will "smoke" in many cases and have to be changed with different values.

 The different TV Help blogs are full of people that have put in the "new and improved" ICs then asked what to do now, all the resistors have smoked or the unit will not start.

 Hitachi has considerable information on the use of these ICs. In all cases they tell you to change the resistors for different values, to allow for the higher idle current.  They also include information regarding alignment for minimum idle current in the circuit. This relates to height, width and hor/vert centre.

The design of the TVs is ok, the IC's fail from AC power bumps or lightning (accumulated damage to junctions over time). Semiconductors will run forever if they have a smooth DC power source, are ventilated to operate within temperature specs, and not overdriven. This was demonstrated when com satelites were first used. They had estimated electronic failure in 4 to 6 years and many last 20+ years.  They are replaced when they run out of manouvering fuel or get an induced power surge from the sun.  

When the IC's run too "hot". there is usually a low ohm resistor that has increased in value and causes higher current output from the chip through the feedback in the circuit design.  The resistor(s) may have changed from 1.8 ohms to 2.5 ohms, the TV will still run, but the IC will fail prematurely.

STK 392-110 will work fine if all the small value resistors are ok and the TV is not subjected to a hotter environment than normal or power line related troubles.  Many RPTVs are mounted in enclosed areas with no air circulations or in direct sunlight. These situations will cause the unit to operate at raised air temperature around the IC's resulting in more failures.  Some people have "hotter" houses than others, their convergence IC's will fail sooner.

If you can redesign the convergence circuits and waste your time replacing all the low ohms resistors, go for it. Otherwise use the STK 392-110, or whatever the manufacturer had in the unit.

I know from experience.  When Hitachi came out with "new and improved" replacement ICs we installed many STK 392-120 for STK392-110 in Hitachi and other makes. The result was many burnt resistors, many call backs and big expense.   

The same applies to the Samsung STK392-010 or STK392-040.  Use the original IC. 

easyab

ALOVRU
ALOVRU's picture
easyab said:

easyab said:

Dwray said: STK392-110 is rated 3amp STK392-120 is rated 4amp STK392-150 is rated 3amp STK392-180 is rated 3amp The higher the Amp rating The Cooler the IC will Run and last longer

I believe the above statement is misleading and could be costly.  It is not the same as a higher rated fuse or a brighter lightbulb.

The various IC's have different specs, one important one is the quiescent current. The higher number STKs have a higher quiescent current (+10%) If you replace a STK 392-110 with an STK 392-150 the small value resistors will "smoke" in many cases and have to be changed with different values.

 The different TV Help blogs are full of people that have put in the "new and improved" ICs then asked what to do now, all the resistors have smoked or the unit will not start.

 Hitachi has considerable information on the use of these ICs. In all cases they tell you to change the resistors for different values, to allow for the higher idle current.  They also include information regarding alignment for minimum idle current in the circuit. This relates to height, width and hor/vert centre.

The design of the TVs is ok, the IC's fail from AC power bumps or lightning (accumulated damage to junctions over time). Semiconductors will run forever if they have a smooth DC power source, are ventilated to operate within temperature specs, and not overdriven. This was demonstrated when com satelites were first used. They had estimated electronic failure in 4 to 6 years and many last 20+ years.  They are replaced when they run out of manouvering fuel or get an induced power surge from the sun.  

When the IC's run too "hot". there is usually a low ohm resistor that has increased in value and causes higher current output from the chip through the feedback in the circuit design.  The resistor(s) may have changed from 1.8 ohms to 2.5 ohms, the TV will still run, but the IC will fail prematurely.

STK 392-110 will work fine if all the small value resistors are ok and the TV is not subjected to a hotter environment than normal or power line related troubles.  Many RPTVs are mounted in enclosed areas with no air circulations or in direct sunlight. These situations will cause the unit to operate at raised air temperature around the IC's resulting in more failures.  Some people have "hotter" houses than others, their convergence IC's will fail sooner.

If you can redesign the convergence circuits and waste your time replacing all the low ohms resistors, go for it. Otherwise use the STK 392-110, or whatever the manufacturer had in the unit.

I know from experience.  When Hitachi came out with "new and improved" replacement ICs we installed many STK 392-120 for STK392-110 in Hitachi and other makes. The result was many burnt resistors, many call backs and big expense.   

The same applies to the Samsung STK392-010 or STK392-040.  Use the original IC. 

easyab

 when an IC fails will it always take a couple of resistors with it?

thanks. 

ALOVRU
ALOVRU's picture
thanks for all the help

thanks for all the help/advice guys, it's all fixed now. i replaced both ICs with original Sanyo STK392-120 from http://richtechparts.com/i-24-STK392_120.html and did a fan upgrade to the convergence board. i put an 80mm 12v arctic cooling fan on each heatsink (fits perfect) and ran a 12v regulator also used Tuniq TX-2 thermal compound for better heat transfer.only two resistors were affected, but were well within 10% of spec so there was no need to change.

rich321
rich321's picture
I have a convergence with my

I have a convergence with my LG RE-39NZ43RB the green would drop from the centre top down below the bottom of the screen after reading all other related convergence problem I have checked both sets of the three resistors 47 K OHMS; 0.125 W; 5% all in range and replaced both convergence CI (STK392-120) (Sanyo) and now I still have a convergence problem but it has change as the green now drops from the centre top down as before but the centre bottom now goes up instead of down making the very centre of the screen perfect I have tried to auto converge, is it possible to do a manual converge ? changing both convergence CI (STK392-120) has altered convergence problem but not cure it please help any ideas welcome

Larry Dillon
Larry Dillon's picture
I have said it one I have

I have said it one I have said it a tousand times!, unless your an engineer and know how to do united lab testing ALWAYS use what is in the set, true, as th other member have said the other STK IC's wil run coller but will load down h bias ans feedback circuits resulting in prematur falure of those circuits.

rich321
rich321's picture
Larry Dillon said:

Larry Dillon said:
I have said it one I have said it a tousand times!, unless your an engineer and know how to do united lab testing ALWAYS use what is in the set, true, as th other member have said the other STK IC's wil run coller but will load down h bias ans feedback circuits resulting in prematur falure of those circuits.

i have replaced the STK IC'S with the same STK IC'S and tested the resistors but still will not auto converge is it scrap

Larry Dillon
Larry Dillon's picture
you probaly have bad feed

you probaly have bad feed pico fuses or links or perhaps, bad feed resistors or supply coils, measure the voltage going to the ic's and see where you loose it.

rich321
rich321's picture
can you tell me what type and

can you tell me what type and value the mat green resistor is on the convergence board posion number R2734 as it is hard to determine the color? ,also the type and value of the 3 mm long component on the convergence board posion number L2704 as i have broken a leg off it.
LG, RE-39NZ43RB / board number MP-03AA(CONV-OUT)6870VS1531A(0)030314 HUR.M.Y
thanks.

rich321
rich321's picture
can you tell me what type and

can you tell me what type and value this resistor is 11.5mm long 3.5mm wide as it is dificult to determine the color?

LG/ RE-39NZ43RB / board number M03AA(CONV-OUT)6870VS1531A(0)03314 HUR.M.Y. board posision number R2734.

I think the colors are orange gray silver gold = 0.38 ohm 1 watt. thanks.

and can you tell me what this one is below with one leg missing 3mm x 2mm posion number L2704 and a symbol under it on the board shown below, thanks.

rich321
rich321's picture
i have now discoverd the

i have now discoverd the resistor is a 3.9 ohm 2 watt metal film as the colors have darkend and the other is a axial lead inductor 1 Microhenry if any one is interested.

iga
iga's picture
I have a problem with red

I have a problem with red color, two resistors (2730 and 2736 are out), i am going to change the stks, about the colors of R2734 resistor in my board ( mp-03aa *conv-out* ) has orange withe gold gold, about the L2704 the colors are brown black and gold, hope this help you

iga
iga's picture
I changed the stks ans the

I changed the stks ans the resistors and all works great now, my inversion in local store was 30.00 dlls more o less becouse i am from mx, chears.

rich321
rich321's picture
iga said:

iga said:
I have a problem with red color, two resistors (2730 and 2736 are out), i am going to change the stks, about the colors of R2734 resistor in my board ( mp-03aa *conv-out* ) has orange withe gold gold, about the L2704 the colors are brown black and gold, hope this help you

iga said:
I have a problem with red color, two resistors (2730 and 2736 are out), i am going to change the stks, about the colors of R2734 resistor in my board ( mp-03aa *conv-out* ) has orange withe gold gold, about the L2704 the colors are brown black and gold, hope this help you

thanks iga i have already replaced R2734 resistor with a 3.9 ohm 2 watt metal film infomation from circuit diagram all works well thanks anyway.

rich321
rich321's picture
larry dillon

larry dillon
more problems with my LG RE-39NZ43RB the sound went dead so I switched the TV off standby for 1 hour when I switched it on again it crackled and clicked so I switched of at the plug for 1 hour and when I switched on this time no sound and I also have a convergence problem I then auto converged the Tv,the convergence is now ok but still no sound.In november I replaced both OF STK392-120 IC and resistors which fixed a convergence problem and a axial lead inductor which I damaged.
Do the convergence IC or the replaced 3.9 ohm resistors operate the sound ?

I would appreciate any help please.

Larry Dillon
Larry Dillon's picture
good pictures you should put

good pictures you should put them all together in a how to do article and submit it to the editor for publication?

Larry Dillon
Larry Dillon's picture
If I am not mistaking I think

If I am not mistaking I think they are 2.2 ohm 2 to 3 watt flamproof resistors

Larry Dillon
Larry Dillon's picture
yes those are 3.9 ohm and and

yes those are 3.9 ohm and and unless your an engineer, always replace the parts with the SAME that you took out including the STK IC"s

rich321
rich321's picture
DJnupi said:

DJnupi said:

Larry Dillon said: If I am not mistaking I think they are 2.2 ohm 2 to 3 watt flamproof resistors

Thanks Larry!
i hope people will google on the model number and end up here.
there is lots of info in all the posts here, good for the world.
about the resistors, 
2 of them are indeed burnt(the green ones top right in the resistor picture), and like in a previous post, the coloured rings changed colour.
the white turned grey. but those that are not burned, have the colours "orange white gold gold",
3.9 ohm, 5% tolerance, and i guess 2 watt.
 i like it better when my resistors burn than something else, so will buy the same.
atleast they are cheap, and you see whats wrong ...
allready ordered 2 sanyo STK 392-120 and will post if it works

replace the blown resistors before the ICs as the blown resistors cause a convergance prob and my damage the ICs
check all resistors out of curcuit (by removing one leg) so as not to trigger semiconductor devices using a multimeter in ohms that best fits the value of the resistors

rich321
rich321's picture
DJnupi said:

DJnupi said:
rich321, i read a bit about lg backprojection tvs,
because i have a convergence problem myself.
i read about a 25v rail in the powersupply, which could be failing.
check if you get 25v
i heared some circuit in the front is also fed by this, so check the power led?
maybe your convergence does work now, and suddenly is taking more power from the supply, thus burning the supply?
readers, check next page for more images!

where is the 25v rail ? i have checked the power led and is ok, thanks 4 the PM hope you get yours sorted.

My lg did not converge after first changing the ICs i then found some blown resistors and changed them and the tv converged ok with no need 4 auto converge.

dayawansha
dayawansha's picture
RICH 321,,,,IF U STILL HAVE

RICH 321,,,,IF U STILL HAVE THE PROB REGARDN UR 'LG' TV,,WRITE TO ME,,I WILL HELP U SURELY,,ANY ONE WITH LG TVs ASK ME,,I AM A SRILANKAN...

dayawansha
dayawansha's picture
Larry Dillon said: What is a

Larry Dillon said: What is a SRILANKAN?

hai,,,,what i meant i am living in a country name srilanka...,,,like any person living in america use to say i am an 'american' right?...............,,,so i am permenently living in srilanka,,,,,thts what i mentioned i am a 'srilankan'....thanks.,,daya.

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