Thursday, June 23, 2011

AKAI LCT3201AD LCT3285TA does not power up - fix power board MLT169A MLT169B

Dec 2012 update:
You can now buy the repair kit or have your power board repaired through our web store.

This is yet another classic in the bad capacitors department, so without further delay here is all you need:

SYMPTOMS may vary since all caps on the board can go bad and it's impossible to know which go bad before which. On that last board shown on the picture below almost all capacitors on the secondary side of the power board were bulged and in cases like this it may become fatal first on the inverter power line or on the main power line. Depending on that the TV may stop powering on or may stop losing back light (display) while still working.

In our case the Akai LCT3285TA had the typical problem of first not wanting to power on the first time the button was pressed and, after a few weeks, not wanting to power on at all.

Click on the pictures below for a higher resolution image and please pardon the quality  - they were made with a phone this time for a difference:

There were a total of 8 apparently bad capacitors on that board - two at the bottom, three in the middle, one at the top and two smaller ones hiding under the heat sink as indicated above.

I think I got a picture of those too, but when I got to posting the blog there was no picture in the phone and the TV was already closed and returned to the customer.

So here are the pictures were available:

Replacing the two below the heat sink required that first the two transistors using that heat sink get unscrewed from it and then the heat sink itself gets de-soldered from the board.

That's pretty much all of can get the caps, find replacement and do it all by doesn't get much easier than can source the parts or you can just buy them at our store...or you can have us repair the board.

Either would be better than replacing the board with another used one that may do the same thing very soon!


Jamey Ratzlaff said...

My caps EC18, 19 & 20 are all blown. The solder joints look like someone has already replaced them. Is there a diode that might have caused them to blow?

Thanks, J

Unknown said...

There probably needs a heat shield because the heat sinks ove heat the capacitors. I had the same problem in xerox power supplies and replacing the capacitors and put something to shield them from the heat. My unit blew the three capacitors between the heat sinks that's what I'm going to do.

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