Mits 55819 vertical deflection failure

[MrPinkNuts]

So I went and did something stupid.. I was fiddling with my piece of garbage DVD player and had the svideo out from it going into the front input on my 55" mitsubishi. I fumbled with the power cord and sent some 120 through ground on the dvd player chassis and I assume through to the tv set.

I've done some research via google..

Now when I try to turn on the set it shuts back down after a couple seconds. Holding menu and input gives the 2-4 error code.. "vertical deflection failure"
It actually came back to life for about half a minute after I had removed the rear input board and poked around a bit..

so if I go on to ebay and find the service manual and some replacement STK392-570 sanyo chips will this fix my problem? Maybe I should get two sets of replacements because I'm feeling cheeky enough to hook the stupid dvd player up again if I can get it fixed. Why don't I just buy a new dvd player? I guess I'm waiting for the new sigma 8630 based x.264 players to get here.. but look what I've gone and done to my precious hd set now

[lcaillo]

The first thing to do is to diagnose the peoblem and not assume that you have bad output ICs. My guess is that if you got is to work by moving things around, you simply have a bad solder connection. This is the most common problem on these sets. Look for bad connections at the output ICs and look for a blown pico fuse. In the power supply secondary.

Frankly, if you can manage to ground the hot side of the a.c. to your set, you are not a good candidate for a DIY repair and I would have a qualified repair tech look at it. If you decide to work on the set yourself, read the information in Sam Goldwasser's FAQ regarding safety at

http://repairfaq.ece.drexel.edu/sam/tshoot.htm#tshgsc

[MrPinkNuts]

well, all the fuses check out ok and the connections on the bottom of the board look solid. I went ahead and ordered the chips (man those things are massive!!) from a guy on ebay who has more than 250 for $9 a pop. I'll let you know how it goes when they get here...

[lcaillo]

I strongly suggest ordering only from the recommended suppliers that you can find in the sticky thread that I created. There are many cheap copies of these chips that have given many folks problems. When you say you checked the fuses, did you check the pico fuses or just the glass fuses?

[MrPinkNuts]

doh I guess I'll go have a look at your parts supplier thread..

I checked all the fuses listed in the service manual. There was only one glass fuse and it was easy to spot but in order to check the rest (eight others, LF251 3A, 5A, 7A & 10A) I had to unscrew and pull the middle board out.

thanks for the pointers leonard!

[MrPinkNuts]

update-

Now the set will stay on as long as the input board is not plugged in on the back, and the menu overlays come up and say power loss, reset clock, etc.

But if I try to power the set on with the board in I get the same problem as before - it shuts itself off after a second or two and the error code is still 2-4, vertical deflection.

I think at this point I will be better off scrounging for a decent used set rather than paying for a tech to come out and tell me theres a problem with a logic circuit that hasn't been in production for five years.

[lcaillo]

When you get menus, you have vertical deflection. Are they distorted in any way?

[MrPinkNuts]

Hi Leonard,

The menus look fine, the same as I remember from before.

The only thing that is strange is when I switch to the DTV input I get a blue band down the middle of the screen.. that could just be a result of leaving the input board off I suppose.

The input board itself looks fine, and I've tried leaving it in with the cord that goes back to the front input connections unplugged with the same results.

I noticed that the coaxial tuners were not part of the input board so I tried to see if I could get anything to show up but no luck with picture or audio there..

[lcaillo]

Odd. Could be something shorted on the input board pulling a supply down. I would have to look at the schematic. Considering the faux pas with the a.c., that would be a good guess. You could have blown anything from a buffer transistor to the switching chip.

The terminal board is not very expensive and hardly worth trying to fix. Part number 935C957001, $70.90 + $25 core.

[MrPinkNuts]

Hmm. I guess it's worth trying a replacement. Should I just call Mitsubishi? I didn't have much luck looking through the recommended parts distributors for that part number.

[lcaillo]

Mitsubishi parts are only available from them directly unless they are common components. You have to get circuit boards from them or through an ASC or dealer.