# Need hep with STK replacement



## karthur (Apr 27, 2010)

I have a Hitachi rear projection (43FDX11B). I have replaced the IK04 and IK05 convergence chips a couple times over the past 5 years. I have just completed the repair again and now I am having trouble.

I "think" that my problem is that I have bridged the pins on 1-2-3 on IK04 when I did the repair. I have tried to follow the trace on the board, but I can't tell where the trace leads. I have also got a service manual for this set, but the diagram does is not plain enough in the manual to tell if they should be bridged or not.

What I need is someone to tell me if these should be bridged or not before I pull the chips out and try to clean the board.

I am "pretty sure" that 1 and 2 was bridged when I took them out. It looks like #3 pin does not actually go anywhere, so it may not matter if its connected to 1 and 2. I have checked the resistors (RK42, 46,50,54,58 and 62) and they are all good.

Thanks,
Kirk


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## lcaillo (May 2, 2006)

Which chips are these? Sorry, but I have not worked on these sets in over 5 years. In most circuits pins 1 & 2 are both ground on the -110 and similar chips, though pin 2 is actually a "virtual ground" and could be floating in some circuits, IIRC. Not sure about the later chips but there are spec sheets for some of them in the convergence repair thread below.

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

If you have had repeated failures you need to read the first ten posts of that thread VERY carefully. It could be cheap chips, or you may have some dc offset or overcorrection causing over heating, or you may need to be more careful about heat sinking.


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## karthur (Apr 27, 2010)

lcaillo said:


> Which chips are these? Sorry, but I have not worked on these sets in over 5 years. In most circuits pins 1 & 2 are both ground on the -110 and similar chips, though pin 2 is actually a "virtual ground" and could be floating in some circuits, IIRC. Not sure about the later chips but there are spec sheets for some of them in the convergence repair thread below.
> 
> http://www.hometheatershack.com/for.../5600-crt-based-rptv-convergence-repairs.html
> 
> If you have had repeated failures you need to read the first ten posts of that thread VERY carefully. It could be cheap chips, or you may have some dc offset or overcorrection causing over heating, or you may need to be more careful about heat sinking.


I have read the Sticky post and there is some really good info there. These are the -150's. I was able to find what I needed in the service manual. Here is a link. It looks like 1-2 are ground, but 3 is not... so I fixed the bridge and the set worked but with some issues. 

Issues being that it would not hold the convergence setting after I powered it off, then on again. However, this morning the set will not even come on and red light on the front panel is blinking. Looks like I will be doing the repair all over again. :hissyfit:

A little history about this set, I first replaced the IC's with STK392-150 back in 2010... then again in Sept 2014.... now the chips went again last week. So, I am no stranger to the repair. I am about ready to toss it and go buy a new TV.:crying: I try to use only Sanyo IC's but this last time, I did order them from China since the TV was working and I had plenty of time for them to be delivered. I have since ordered STK394-250 to replace these... should be here on 1/4/16.

I am going to lift one leg on the output resistors and check the value of all of them today. So I may be replacing resistors too.

Will post back on how it goes.

Kirk

P.S. One question: In the X480296 repair kit info, it says to replace the STK394-110 with STK394-160. I seen where you posted the block diagram for the -250, but not for the -160. Is it OK to use the STK394-250 instead of the -160?


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## lcaillo (May 2, 2006)

Sorry, but I can't say for sure. I don't recall the compatability.

Check for bad connections.


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## karthur (Apr 27, 2010)

If I compare the diagram for the STK394-250 Vs. STK392-120, the only difference is Pin#2. On the -120 it is grounded, but on the 394-250 it is the mute input. (low input: output disabled.... High input: output enabled).

If I use the 394-250, you think it would work if I just don't connect the pin #2? Or is there a way to get the mute input to the IC?

Edit: I just looked at the schematic for the board. Pin #2 is to ground and Pin#3 is not even used. So I am thinking the STK394-250 should work. Here is a link to the portion of the convergence diagram that shows the connections.


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## karthur (Apr 27, 2010)

Update:
Just installed the STK394-250. Set comes on, but I can't adjust the convergence. I tried pressing the "Service Only" button first and then turning the set on.... still no adjustment. I checked the voltages at PDKP and it is +28/-28 volts where it is supposed to be so I am sure its getting the proper voltage to the board. I have checked and double checked for a solder bridge and my connections. All of the resistors check out.

Any suggestions? Guess my best bet is to order a set of STK392-160 and put them in.


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## lcaillo (May 2, 2006)

karthur said:


> Update:
> Just installed the STK394-250. Set comes on, but I can't adjust the convergence. I tried pressing the "Service Only" button first and then turning the set on.... still no adjustment. I checked the voltages at PDKP and it is +28/-28 volts where it is supposed to be so I am sure its getting the proper voltage to the board. I have checked and double checked for a solder bridge and my connections. All of the resistors check out.
> 
> Any suggestions? Guess my best bet is to order a set of STK392-160 and put them in.


Are the output resistors ok?


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## karthur (Apr 27, 2010)

I checked RK42, 46, 50, 54, 58, 62. These check out to be good. These are the ones shown in the "X480296 Repair kit". I also probed around in some of the other ones, but couldn't find any that were open. None look like they are burnt.


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## lcaillo (May 2, 2006)

Check for bad solder joints or loose connectors. If you have power to the ICs and cannot adjust, you either have another failed chip or more likely something is not connected.


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## karthur (Apr 27, 2010)

Best Buy had what I needed to fix it..... A brand new 50 inch LG.

I bought this Hitachi in 2002. It has been a pretty good set. I hate to see it go.

Is there anything inside the set worth pulling out before I haul it off?

Thanks for the help.


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