Ok, I have repaired hundreds of these sets--this one uses two STK-392-570 convergence chips---I have seen many of them where in the first 30 minutes or so the chips are intermittent, I call it Flakey----you need to replace both chips---very common on this set.
The chips can be purchased on Ebay for less than 14 dollars plus shipping (for a pair)----the real question is are you able to do this repair if I provide you with detailed instructions for this model?
If you are able to do this you can save a lot of money--most shops are going to get 300-400 for this kind of repair----sooner or later if you keep using the set this way---it will go dead---there are fuses that protect the chips--when one goes the set will instantly shut off.
There is a very simple reason this happens--these two chips are about 2 1/2 inches wide and 1 1/2 inches tall with 18 pins each---the back of each chip is metal and a white grease is applied to each chip before it is mounted to a large metal heat sink--after some years the grease dries out and one of the chips goes because it cannot move the heat fast enough to stay cool.
Let me know what level of soldering skill you have--I have start to finish instructions I am willing to post here for you----if you remove the front speaker grill on the set and the inspection plate behind it you will see the two chips on the center circuit board on a large metal heat sink---
If you are not able to do this repair--I have lots of free advice about how to get it fixed---I have fixed hundreds of these sets---once the chips are replaced and the set adjusted---it will not have this problem again for 5-8 years----very good sets and much more dependable than LCD or Plasma sets.
IF YOU HAVE ANY QUESTIONS OR NEED HELP-do not hesitate to ask me here---I am here to help people.
Regards, SD TECH
Comments:
Oct 08, 2009
- you want the information posted here? The rules here do not permit me to ask or Give my email--I will post them here-several pages--you will have to copy them from here.
Oct 19, 2009
- The instructions are a bit long so I am going to post them here in several parts--the site cannot handle the whole thing:
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392-570 Replacement
Mitsubishi convergence IC replacement: this applies to sets
that use (2) STK-392-570
The Idea here is to get the Middle Circuit board out so you
can replace the Convergence Ic’s.
HERE is what you will need: (most of this you can buy on the
internet or at local electronics stores)
Two new: STK-392-570 CONVERGENCE IC’S
One good soldering iron
Solder
De soldering braid or wick
Liquid flux
Heat sink compound (grease)
Denatured alcohol
One short Philips screwdriver
One small clean toothbrush
One electric screw gun to REMOVE screws
Turn the set on and examine the picture for how the
Convergence looks bad---when you are done examine it again---once in a great
while you will get and install a new IC that is bad. Remember this when you
have finished—if the convergence is still bad but different from what you
started with you may have installed a new I.C. that was bad.
Turn the Set off.
- Unplug
set.
- Remove
back cover.
- Remove
front speaker grill and inspection plate behind it.
- Remove
the 2 or 3 black screws that go thru the back edge of the plastic frame
that hold the chassis down.
- Where
all the video and audio jacks are on the right edge of them you will see a
diagonal plastic (Black) remove the two brass screws from the outside
edge, remove another to the right bottom and a third smaller screw forward
and to the left; remove plastic piece and all four screws and set them
aside.
- Look
carefully at main board in center of the set.
- You
will find a number of screws hold it into the plastic frame.
- Towards
the left back edge of this (to the right of the plastic you removed) you
will find a metal cover with a small screw on either end. It has a lot of round holes punched in
it.
- Remove
both screws and pull the shield up and off---remove the board beneath it
by releasing the two tabs on the bottom right side and pulling the board
out—handle it with care as it is the digital convergence board that stores
the set’s memory of adjustments.
Set it aside
- At
this point you need to pull the entire Chassis back at least a few
inches---If it does not slide back look for a plastic latch on either side
near the front of it. Some sets
have the latches on the left or right side—black plastic tabs that lift
up.
Oct 19, 2009
- IF ANYONE NEEDS THE COMPLETE INSTRUCTIONS LET ME KNOW--I HAVE JUST POSTED HERE THE FIRST PAGE TO GIVE YOU AN IDEA--Thanks Gary--glad to hear it turned out good---you are right--it is not the most easy set to do this with---but I have already got a lot of thanks from people who were able to do the repair!
SD TECH
Expert
