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#1
10-28-2006, 08:31 AM
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1992 Mitsu. large CRT set...bad caps?
I saw a really big (36"? 40"?) CRT Mitsubishi set at a thrift store yesterday. It was made in 1992 and powers up. There is snow on the screen but the scan lines look bunched together in the center like there is a bad cap in the vertical.
Is this a model which will have tons of bad caps and will end up being a "white elephant" or did the mitsubishi bad cap phenomenon come to an end by 1992? I don't want to get the set if it's likely to have a bunch of future cap failures. 
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#2
10-28-2006, 08:57 AM
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If the crt is good and the price is right, change the bad caps and you will have a set with a heck of a nice picture. Not sure if that one has the PIP board problem common to the mid nineties ones, but even that is easy to fix.
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#3
10-28-2006, 12:00 PM
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If caps don't do it, replace the scan diode that supplies the B+ to the vertical chip. I recently saw one that measured good with the diode check on my Fluke meter, and there was B+ to the chip. Picture was shrunken just like when caps are leaky, but the cause was aleaking diode! That was a CS-40501 40" crt set.
Charles
__________________
Collecting & restoring TVs in Los Angeles since age 10
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#4
10-28-2006, 03:25 PM
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Chad,
Is that the big monstrous Mitsubishi set with the particleboard cabinet and large assortment of a/v connections on the back and if I remember correctly, an exhaust fan for air circulation? Those are awesome sets and have a great picture, it would be well worth picking it up. The high school I used to work for had several of those, some mounted on massive wall brackets, and some on carts. The only drawback - they weigh a ton!!
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#5
10-28-2006, 06:50 PM
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Just replace all of the bad caps that show any signs of leaking and the set will last. It's a lot of work but the picture on those sets is great.Look at the negative leads of all the electrolytics closely and any evidence on the board. Take the large ones on the secondary out and check them. Most likely they will be leaking as well as a 470 Uf 50v cap in the power supply. Replace the 1 Uf 160v in the primary of the horizontal driver circuit whether it checks good or not. This will be good preventative maintenance to prevent Hor out transistor failure down the line. As for the obvious problem it could be capacitors or the diode that was mentioned.1993 was the year they introduced the troublesome PIP module so this one shouldn't have that problem.I've repaired a lot of these old Mitsubishis sometimes replacing as many as 50 capacitors. I do a thorough job checking and replacing and cleaning up corrosion and they last after I do them. The customers that own these usually go for the repair as they cost a lot when they were new.The crts last forever and I've never seen a bad flyback on one either.Only saw 1 1989 model with a weak tube about a year or so ago. The guy was retired and told me it was on 16 hours a day every day.
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#6
10-28-2006, 08:02 PM
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Thanks a lot for your help...I think I will go ahead and probably get it. I saw it again today but the truck was loaded up with trash to haul to the dump so I couldn't pick it up. Am not sure how much they want but should be reasonable. It is a large upright console with an black ebony wood type finish.
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