Help!
First and foremost, this board has already been an immense help to me—just wanted to make sure I said a big thank you to you people up front.
My problem is with an (inherited) ’01 Mitsubishi WS-65857. Received it from a relative who hadn’t had it in use for a while, sat in a living room for about a year. Tested it on site, powered up and looked great. Took it home, no problems, powered up at the house. Ran across this board and started making a list of potential tweaks for the new-to-us TV, and came home from work on day two to hear my wife’s “Uh-oh”. TV powered on, blue screened for a moment, static out of speakers, screen cut out entirely, sound still worked. Input button still worked, power button still worked. Cycled TV on/off a few times, checked my surge protector, and tried again. Same result, each time. A loud double pop and the screen cut out, audio (getting weaker) still worked. Unplugged set, waited 30 mins, plugged back in, tried again. TV powered on by remote only, VERY weak audio (which faded out entirely in a few seconds), power button no longer worked. I left TV on for 10 mins or so, to see if it was a warm-up issue, but no dice.
So I unplugged the TV, let the caps drain overnight, and opened the back. From what I can tell, a very slow CRT leak from the center lamp had been hitting the middle circuit board over a period of years, which had capillaried out over the dust on the chassis to reach about 40% of the horizontal area of all three boards, mostly contained to the middle board, where some green corrosion had formed over a few hard circuits behind the large central heat sink (I can describe this location better if desired). Powering on and running the TV for a few hours had hastened the fluid loss, I found wet fluid on the red CRT lamp connector, and on the middle board at the corrosion site, nowhere else in the cabinet.
Read here about CRT leaks, took the chassis out of the cabinet (yes, I marked my connections), and went after the whole board with a toothbrush, Q-tips, and acetone. Corrosion wiped right up, wiring looked good, most of the rest of the board cleaned as well. All caps on the entire board look OK, not puffed, blown, or leaking. Plugged everything back in, same problem—TV LED blinks three times at plug-in, power button does not respond, remote control WILL power on set, no discernable audio or picture, power LED is steady green when on.
Did I just inherit a paperweight, or is there hope?
TIA,
mtglick
Should I interpret the resounding silence as respect for the dead? :) (sigh)
Just in case it makes a difference, as far as I can tell the fuses are all intact.
I am thinking about this one. I am mulling over the situation. So please do not think you are being ignored.
Thank you! If there is any addl. info you need, let me know and I'll post as soon as I can.
This could be a tough repair my friend. I have seen leakage from the CRT's that ruin the boards. It is not the liquid, per say, but the corrosion the liquid causes. Also the fact that you heard popping sounds is or could be an indication something blew out. You will need to just start doing electronic troubleshooting from scratch. Another suggestion, would be to go to ptscorp.com, get the telephone number, call them and see if they still repair those Printed Circuit boards. Do not tell them it had liquid on it, so clean the board up well. They may even have an exchange for you. Good Luck, and let us know how you make out with this TV set.
Thanks for the lead, if anything else occurs to you let me know. The boards themselves look pretty good--is there something I should look for/remove (i.e. hidden corrosion) from the boards prior to shipping them to pts?
Will post when I have a result.
nope, just make sure it is clean, and call them to make sure they will service the board.
Just a follow-up, PTS can do the whole chassis for $300 plus ship. I'm going to pack and ship this week, and will let you know what the end result is!
Thanks again,
mtglick
You are still going to have to correct the CRT leak you know.
Thanks for the reminder, I'm trying to take it one step at a time--I figured there was no point correcting the leak if the TV was unsalvageable.
Hi Larry,
I have been reviewing these posts and your advice is terrific. I have a similar CRT leakage / power cycling problem but with my Mitsubishi VS-60803. I am a certified bench tech and know my way around PCBs, but I don't have a service manual or any schematics to guide me in my troubleshooting. I can see where the Blue CRT has been leaking onto the Signal board and I highly suspect that this is causing an intermittent short. I can try pulling this board and just cleaning it, but it would be great if I could check some known test points to see if there are any bad components.
Any/all help would be greatly appreciated.
Thanks! Ken
Email: [email protected]
Nope, sorry i do not have this service manual but you can download one or get a paper copy from HERE. You will need to correct the leak. I do not know if Mitsubishi has any gaskets for this tube. We used to just replace the entire picture tube to correct it or install a plastic piece under the leak that would direct the liquid away from the printed circuit boards. Good Luck
Hi Larry.. reading the forum you already helped me with the blinking light on my WS-65813 THANK YOU SO MUCH ... fixing that problem I saw a small CRT leak from the left lamp.. It still didnt get bad enough to reach the boards due to some cables... But what can I do to prevent it and/or is there a fix?
Thanks again
Mark
[email protected]