Trinitron KV-36XBR250 Last Try

[YamahaFreak]

I really do not want to trash this set, but I am about out of options/ideas. The set's mainboard is physically cracked in two places, likely from mishandling, and likely why it was dumped. When plugged in and turned on, I get everything but high voltage and a picture. (Have not checked for CRT filament.) I have degauss, sound, controls for volume/channel/input, etc., just no HV or picture. Standby LED flashes unendingly.

I am looking for a replacement mainboard as a last ditch effort at restoring this set. Would anyone here happen to have one? Again, this is the KV-36XBR250; it has the controls for volume, channel, and power on the top of the set.

[Dangler]

Can you bridge the cracks with small wires soldered to the board? That might take care of the problem.

[radiotvnut]

I've done that before with good results. Of course, there was that one set where I spent hours jumping across all the cracked traces, only to discover that the shadowmask inside the CRT was damaged. I've also junked a few TV's where there were too many small traces damaged and I didn't feel the set was worth the effort. Then, there was that 20" APEX silver TV/DVD combo that someone wanted me to fix because they had sentimental attachment to it (whatever). That set had been dropped and the board suffered major breaks around the flyback transformer. I took a chance and spent about two hours fixing the cracks, the set worked, she paid me well for my trouble, and everyone was happy.

[wa2ise]

Originally Posted by Dangler

Can you bridge the cracks with small wires soldered to the board?

I've done that, and I also added some epoxy to the cracks to try to strengthen it.

[YamahaFreak]

Thanks for the replies, guys. My mate, who has consoderable soldering skills, has looked it over and tried his best to repair the obviously broken traces, but with no luck. D: I wonder if I couldn't ship the board to someone here to get a better opinion?

[AiboPet]

This "cracked board" thing is almost 100% of the problems with the little micro TV sets I collect. Dirty pots....and almost ALWAYS some crack somewhere around the flyback. These little tiny sets get tossed and dropped alot, and the flyback is the one item with enough mass to cause a break in the board.

Little wires from some solder point North and South of the break will almost ALWAYS get the little bugger playing again. Put on your GOOD eyes when looking for these cracks. If in doubt....put your meter on the little beep/diode/resistance setting...and check for continuity between a North and South point of what you think looks like a break.

If you use little wires for jumpers....make sure they are insulated unless it's a very small low voltage jumper. Try and keep from bunching any of the wires close to eachother, especially around the flyback traces.

Very small sets....or anything you suspect was dropped, you have to check the CRT socket and anything like a "neck board". PULL the board from the CRT socket and see all the pins ARE there and not broken off...and then check for cracks on that CRT board. This is a good time to also make sure a drop hasn't broken the VERY end of the CRT off and LIBERATED the vacuum.

[rpm1200]

I wonder if you might be able to get a main board from a different model, then program the ID in the service menu to make it work. I found this page at Encompass Parts:
http://www.encompassparts.com/item/3...A/Phase_Iii,_A
that suggests you might be able to use the board from a KV36FS, KV36FS10 or KV36FV15 instead... worth a try, what do you have to lose at this point?

[holmesuser01]

I had a dead 27EXR25 set with a cracked main chassis board. I worked on it for about 10 days re-tracing my work with tiny lengths of wire and an ohmmeter. Finally, it was all done, but would not turn on.

Turned out that the regulator on the G module was bad. I replaced it, and the set has been working just fine since 2003... when I got it. It is now on its 2nd CRT, and still going strong!

[YamahaFreak]

Well, my father got tired of this set sitting around, so after nine months, I salvaged the speakers from it and curbed it. I am surprised the trash men actually took it...

[dieseljeep]

Originally Posted by YamahaFreak

Well, my father got tired of this set sitting around, so after nine months, I salvaged the speakers from it and curbed it. I am surprised the trash men actually took it...

Especially a heavy beast like that one.

[old_coot88]

Originally Posted by wa2ise

I've done that, and I also added some epoxy to the cracks to try to strengthen it.

Did that with many cracked boards over the years too, adding epoxy to stabilize the repair.
One particularly nasty repair did not involve cracked boards, but deeply burned-in char paths from soda pop being spilled into the set. It created a complex of B plus-to-ground char paths in the board, shorting out the B supply which kicked the breaker. Had to jump the breaker to make the char paths incandesce white so I could see 'em. After thorough cleaning, sealed the cleaned-out channels with epoxy.
The power supply diodes survived the brutalization, but i replaced 'em anyway.
Customer was very happy.

[YamahaFreak]

Originally Posted by dieseljeep

Especially a heavy beast like that one.

Indeed! I actually had the set apart by the road the first trash night of the week, and they refused to take it. I put it back together, and they took it on the next trash morning.