WD-65735 needs help!
 

Mitsubishi WD-65735 ballast no-power situation.

Yep, it finally happened. The Mitsu 65" is dead, and I might be in for a rather hefty parts bill unless someone has a better idea.

Just put a third bulb in the set, I've had it for 5 years. It's on most of the day, so that's why I went through so many bulbs. Only 2 weeks after new bulb #3 went in, I come home from work and the wife says TV is broke. Sure enough, no light out the back. I figure the new bulb went out, but it's fine. Troubleshot it down to some sort of issue with the main board underneath the power supply.

Here's what I have so far:

There is a pin labeled 'lamp relay' on the power supply board, which receives around 3 volts DC from the main board when the lamp is (supposed to be) on. 3 volts goes to a discrete transistor driver circuit, which then activates the relays for the lamp ballast. It's the same exact circuit for mains input, only mains has a single relay. So I make the assumption that the ballast is not being told to turn on, and jumper 'main relay' to 'lamp relay' on the power supply. Kills the whole set, there's a short somewhere in the lamp circuit so that any time I jumper it the mains relay goes open. I removed the lamp relay wire from its connector on the power supply side and tried again, light comes on no problem when I jumper it. I assume this means the main board is bad ($400, f that), or it thinks there is a fault in the lamp so it is off for a reason...

I don't feel safe leaving it jumpered, because if there is an overheat condition I could be setting myself up for a fire. So what's my best shot at fixing this, besides the uber expensive main board replacement? Should I try a ballast board first, on the off chance the fault lies there?

Does the led flash any codes? That will get you closer to the issue. May take several tries, but a code will eventually show up. I can get the parts for very little here. let me know what you need and I'll be more than happy to send them your way. BTW, those are pretty decent TV's and pretty simple to repair/disassemble. Have one at my shop for sale and I just repaired a customers(DLP chip)

Any chance you could post me a main board and a ballast for troubleshooting purposes? If either of them ends up fixing the problem, I'll pay and send what I don't use back.

No codes, because the green timer light never stops flashing. Yes, they are very nice sets and make a great quality picture. That's why I'd like to keep it, it's given me good service till now so I can't see dumping it for it's first offense. :smoke:

Any chance you could post me a main board and a ballast for troubleshooting purposes? If either of them ends up fixing the problem, I'll pay and send what I don't use back.

Stupid double posting work computers!

I'd try to fix that Mitsu. I just googled Mitsubishi, and found out that they are now out of the rear projection TV business for good. Not only that, but RPTV itself is a dead technology, having been upstaged by today's flat-panel LCD and plasma televisions.

If your RPTV cannot be repaired, I would say replace it with a similar size modern LCD or plasma set and don't look back. Unless you have some special reason for wanting to keep the Mitsu RPTV, you would probably, IMO, be better off with a modern flat screen. Just a thought.

Why this set? Because the image quality is as good as an LCD (if not better than some) plus you could not approach the price with a 64 inch LCD at the time.

The discussion makes me wince, though. Mine is used only about an hour a day, so maybe that's all that's keeping me from the same failure point.

I don't understand LCD's pushing these out of the market, it seems a poor judgment to me to insist on something thinner at a higher price. The depth is not that great, and you can't put anything else on that side of the room anyway whether you have something thinner or not. It's not at all like the old CRT rear projos that really ate up floor space.

Wayne,

It's these damn kids and their newfangled thin tubeless sets, and cars with wheels that are too big- you wouldn't understand. :D

You're right of course, there was no way to touch a 65" flat panel for anywhere close to what I paid for this. Plus the picture quality is very good on this set, I hate trashing anything that works as god as this one does (did). If mstaton can get the boards for it I'll give it a go, if not it may not be economically viable to repair. In that case I may have to store it till a donor set pops up on CL.

I think the problem, if you want to call it that, is that RPTVs use (by 21st century standards) outdated technology, and today's TV makers don't want to use 25-year-old tech when modern flat screens use less power and take up less room than the older sets did. Don't forget, a large-screen RPTV set can draw up to 500 watts, depending on brightness, etc. settings. Years ago, large-screen console b&w tube TVs were notorious for being power hogs, some sets drawing 300+ watts in normal operation.

Early RPTVs may have been as large as you say, but I've seen pictures of sets, such as Zenith's Space Screen 45 (I saw an old ad for one on Youtube recently), that take up no more space in an average-sized living room than a traditional 25" CRT console TV -- and with the SS45, the screen disappeared into the cabinet when the set was turned off. This may have been a selling point for the SS45s, but the mechanism that raised and lowered the screen would fail after a period of time. The screens were fixed permanently in the up (viewing) position and the drive motors unplugged when the drive system failed. No more disappearing screen, but at least the TV still worked, and many such sets were kept and used until they developed more serious problems, causing the owner to junk them.

PM your address and I'll get them out next week

Apparently you haven't read any labels lately, my folks have a 46" plasma that draws over 400 watts from the outlet. My 65" DLP draws about the same, but with a much larger picture. My CTC-4 draws under 400...

Of course, for the price you paid then (if you bought it new at a regular store) plus the three bulbs, you could definitely get a 65-inch flat-panel set today. That is why rear-projection sets have now gone away, the price advantage is not there anymore, though they were certainly a good value for many years.

It's pointless stating what one 'could' have done, it's not like I was going to sit there without TV for 5 years while saving the money I wasn't spending on bulbs for a better unit. :D Besides, some of the flat panels have pretty horrible track records too. How many times this year am I going to hear about another y-sus board going out, or a power supply getting taken out by a bulging capacitor? My Mitsu had no bad caps on it, all the important ones were actually Nichicons which surprised me a little.


I have an update:

I actually did the shameful thing, and called the TV repair guy. Yeah yeah, I know. For $50 they stuck it on their bench, and confirmed what I already knew: the main board is toast, but interestingly it seems to have been caused by the DMD board shorting out so I need both. Mitsu say they have both parts available, $300 for the main board and DMD for around $100. I'm hoping the repair place tells me the same, so this can be resolved for around $500. The 50 I paid to have it picked up applies to the final bill as well, so hopefully this will be resolved soon without a lot of bitching about money. They were surprised I actually wanted it fixed, but it's been a good runner for me and I can't see giving it up if I can get 5 more years out of it. How many flat screens are still around after 10 years?

Sorry miniman, all my sources did not come up with any parts. They said that they are hard to find that work. :(

None of the internet places had any either (shop jimmy, ect), but Mitsu claim they are in stock. Probably a lot of warranty work being done on these. What's interesting is mine didn't fail in the same way I usually read about, most people are complaining of 'dots' or 'measles'. I had no such defect. In fact the DLP chip in mine looked brand new after I dusted it off, no haze or halo or anything. I think it's just a case of overheated parts to be honest, the fans in this set don't move near enough air to keep it cool. So when I get it back, the first thing I'll do is take the fan off my CTC-4 and put it on the DLP set. Color wheels, cooling fans.... something all too familiar about all of this. :yes: