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Discussion Starter · #1 ·
I have a mitsu WD-62525. I believe my lamp died a couple months ago. I have since purchased two replacement lamps...neither of which seems to work. I have gone as far as attaching leads to the lamp so that I can test for voltage when the tv turns on. I see 49VAC when the tv turns on. After a couple minutes the lamp light glows red.


I have checked for continuity between the two lamp contacts, there is none. I checked a regular 60w ac light, which gives continuity. I'm wondering if anyone can test their known to be good lamp for continuity to see if it should have continuity?
 

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I am currently having a similar problem with the same Mitsu. The lamp has finally givien up and I tried replacing it with the one I purchased from Mitsu last year when the set told I should order one. Instead of working it is doing nothing. I checked to see the lamp they sent me and they had substituted 915P020010 which is the correct lamp for the set with 915P026010-A which according to one of the sites I visited says will not work in our sets. Is this the lamp you received as well?

I currently have an e-mail sent in to Mitsu service awaiting their reply.
 

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Quote:
Originally Posted by jetrep /forum/post/12915917


The lamps I tried (2) were identical to the original. I bought Sony and have the MItsu sitting in a box in the basement.

There's a fairly common problem with these sets where several capacitors on the power board swell/leak resulting in a degraded 5V supply to the ballast card (the end result is a red lamp light). A handful of people here have successfully replaced these caps.


The service manuals will facilitate getting to the power board:


V26 Chassis Replacement Manual
http://www.megaupload.com/?d=6MKC3A3V


TV Service Manual (V26):
http://www.megaupload.com/?d=OMFZ8E7B


See this link for pictures:

http://www.avsforum.com/avs-vb/showt...8#post11856198


It's the two 3300 uF's on the left side of the board (next to the metal heat sink) that cause the red lamp problem. You can use Mouser.com to buy replacements:


Part Number: 647-UHE1A332MHD

Voltage: 10V

Capacitance: 3300uF
 

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Quote:
Originally Posted by jetrep /forum/post/9512706


I'm beginning to believe a properly functioning mercury lamp should not have continuity between its contacts

The TV's ballast card initially issues a high voltage pulse to ignite the lamp and then scales back to a lower voltage to hold it. There's continuous synchronization between the ballast card and the light engine throughout the process. If you get a red lamp error & replacing the lamp doesn't help, your problem is likely one of the following:


1. bad power board (see previous post about capacitors)

2. bad ballast board (can replace with generic ballast board for cheap)

3. bad light engine (no cheap fix here)


Check back here if it's not #1 and I can direct you on how to differentiate between #2 and #3.
 

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Discussion Starter · #10 ·

Quote:
Originally Posted by noplasma /forum/post/12916375


The TV's ballast card initially issues a high voltage pulse to ignite the lamp and then scales back to a lower voltage to hold it. There's continuous synchronization between the ballast card and the light engine throughout the process. If you get a red lamp error & replacing the lamp doesn't help, your problem is likely one of the following:


1. bad power board (see previous post about capacitors)

2. bad ballast board (can replace with generic ballast board for cheap)

3. bad light engine (no cheap fix here)


Check back here if it's not #1 and I can direct you on how to differentiate between #2 and #3.

Just opened it up and checked out the capacitors. They all look good
 

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Quote:
Originally Posted by jetrep /forum/post/12923517


Just opened it up and checked out the capacitors. They all look good

Have you verified that the 5V supply is good? There's a Test Point on the power board (5V TP). Remember that even slight bulging indicates a bad cap (it doesn't have to be leaking). But if your 5V supply is near 5V, that provides final confirmation that the caps are good.


The link below provides info on differentiating whether it's your light engine or ballast card. If it's your ballast card, you can replace that generically for like $60, I think.

http://www.avsforum.com/avs-vb/showt...6#post11713496
 

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After reading everything , over and over I worked up the courage to crack the back of my set, and there it is both capacitors are popping just like in your posts and so I am going to order the replacements and give them a try. Is there anything I should pay attention when removing the board in order to replace these?

You folks are awesome, I would never have tried this on my own.
 

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Discussion Starter · #13 ·
I checked PA on the power board. I get 5V across 1&3 and 2&3. Further inspection showed no signs of bulging on any caps.


I moved on to J14. On startup I get no voltage across 8 & LAMPEN. I get a constant 3.3V across 8 & LAMPLITZ. I get a constant 3.3 across LAMPEN to chassis ground. Constant 0V across chassis ground and LAMPLITZ. 1.6V across 8 & 1...and 5V from 1 to chassis ground.


What now?
 

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Quote:
Originally Posted by Ray65 /forum/post/12963998


After reading everything , over and over I worked up the courage to crack the back of my set, and there it is both capacitors are popping just like in your posts and so I am going to order the replacements and give them a try. Is there anything I should pay attention when removing the board in order to replace these?

You folks are awesome, I would never have tried this on my own.

The main thing is that if you don't have much experience at soldering, be careful not to splatter and be sure you don't make a "solder ball" that has little connectivity to the board metallization. And remember to match + and - correctly on the new caps.
 

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Quote:
Originally Posted by jetrep /forum/post/12964326


I checked PA on the power board. I get 5V across 1&3 and 2&3. Further inspection showed no signs of bulging on any caps.


I moved on to J14. On startup I get no voltage across 8 & LAMPEN. I get a constant 3.3V across 8 & LAMPLITZ. I get a constant 3.3 across LAMPEN to chassis ground. Constant 0V across chassis ground and LAMPLITZ. 1.6V across 8 & 1...and 5V from 1 to chassis ground.


What now?

See image4 at this link:

http://www.avsforum.com/avs-vb/showt...8#post11533188


In this image, the scope reading shows normal start-up behavior. The top yellow line is LAMPLITZ and the bottom green line is LAMPEN. The differences in your measurements probably have more to do with measurement time (with respect to the TV power-on cycle) than whether you're measuring against the J14 ground or chassis ground. I recommend that you make all of your measurements against the J14 ground and try to estimate what the off/on changes are. If you never see LAMPEN change with respect to that ground, I would suspect the Light Engine.


Other data points: do you ever hear a "click" from the spark-gap indicating that the TV is trying to light the lamp? And did you confirm that all the voltage test points on the board board are correct?


p.s. there are a few more troubleshooting pics at:

http://www.avsforum.com/avs-vb/showt...0#post11530780
 

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Quote:
Originally Posted by Ray65 /forum/post/12964371

Attachment 100658

Attachment 100659


These are what I found in my set, there is also a slight swelling in a couple of the 1000 uf capacitors, which I believe the correct number for these is 647-UHM1C102MPD from mouser.

It's probably a good idea to replace all visibly swollen caps while you have the board out.
 

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Well I got the caps in today, and I could barely contain myself to make it through the day at work and not leave early to get a jump on the mission.

The de-soldering was tough but I got thru it and I put everything back in and when I plugged it in my light changed, it was flashing yellow now, duh.. I hadn't put the filter cover back on and there is a sensor there as well like on the actual lamp cover. By the way I put my old lamp back in and everything is happy, I have a picture, sound and everything is beautiful.


Thank you so very much noplasma



I would never have attempted this without the great information you folks have on this forum. You are truly awesome, I can't tell you how happy I am have to saved a load of money and kept from trashing my set.
 
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