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· Registered
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Discussion Starter · #1 ·
I was lucky enough to be given a Mitsu VS-55707 by a VERY frustrated owner. The set would work beautifully for minutes or weeks and then suddenly shut off. Tries at turning it back on again only resulted in the fist-pounding two second turn off.
The first things I did were fairly standard, cleaned it out, looked for bad caps, leaky CRT’s etc. Nothing looked out of the ordinary. Hooked everything up and since it was working great I left it to the kids for “beta” testing.
It took a week or so, but it did finally shut down. I poked about the back of it and didn’t really do anything more than pull the HV off the flyback, heard a static pop and put it back on. Turned on the TV and viola, it worked great for another few weeks. No, I do NOT consider that a fix or faith healing! Just unlucky that something that was wrong got reset and made it impossible to do any more troubleshooting until the problem came back again.
The next time it went out I got a bit more involved before just pulling things. I took out the signal component board (on this model the convergence and tuning or combined on one PCB). Nothing out of the ordinary still, other than one of the cable terminals at some time had been almost completely pulled off the TV. Probably by someone moving the TV further than the cable cord would allow. While I had it out, I went ahead and touched up all the solders on the convergence IC’s. Put it all back together and again, it worked for a few weeks.
The next time it went out the symptoms increased. The coaxial A and B inputs no longer work at all. All of the RCA inputs work fine; the shut is a bit more frequent. I didn’t really have the time to do much at this point (plus I had just had major reconstructive surgery on my right wrist) so the set sat for about 3 months being used on occasion by the teens with their video games primarily… when it would turn on.
All of this has taken pretty close to a year. The set still does its shut down. I get the 2-4 vertical deflection error code, wait a bit then get the 1-2 skiddo no error code.
In the mean time, wrist healed and back to work again. I did a coolant change on my brother in laws TV, worked great. So I got a bit more ambitious and picked up the broken TV’s (projection) I could find in the local area for next to free. One of them was a 53” Hitachi with a very obvious convergence problem. A bit of poking about the threads here and ordered up 2 sets of stk392-150 IC’s plus some support resistors, pico fuses etc.
The Hitachi is very happy and looks fantastic! The mitsu is still grumpy and needs a few days for his caffeine to kick in.

That brings us up to today. A few minutes ago I was looking for some answers to this here in the forums and ran across this thread;
The symptoms were VERY close to what I had;


From a "Cold Start" (after having been off an hour or longer) the set will not come on if
the previous viewer shut the set off while the YPrPb input was selected. It takes literally
about 50 presses of the on button (either remote or front of set) to get it to stay on. When
attempting to turn on the green power LED will come on for about 3 secs then immediately go
back off.

If you shut off the YPrPb input source material (HD sat receiver) the set may then come on a
few attempts sooner.

If the previous viewer had selected any other input besides YPrPb before turning the set
off, then it will immediately turn on and work fine provided you do not quickly
switch to the YPrPb input. If you switch to YPrPb before the set has been on at least 2 or
3 minutes the set will immediately shut down.”

The set had been unwilling to turn on at all after I changed out the convergence chips. I read this tid bit and great a brain storm, “lets disconnect the cable!”
So I did, and yup, it started right up without hesitating and gave the old 1-2 code.

At this point I am debating pulling the signal comp. board again and removing all of the cable input from it and trying again. Or, I could just let it go as is and not worry about more repairs until it presents more issues. Either way I am not in a hurry. We have the Hitachi for the kids video games and a very nice Samsung DLP for movies.

I will post more on this set as it presents. Please share your thoughts with me.

· Plain ole user
11,205 Posts
Check for bad solder joints on the vertical yoke wires at the connectors on the yokes. Also, these sets have had some caps go bad in the low voltage regulator circuits and the main PS. You need an ESR meter to find them, usually. Other possibilities are a coolant leak that you have missed. This is the MOST common issue on this model causing intermittent problems.
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