Does anyone in this forum know anything about this old dinosaur? It was made in 1989, and I'm having trouble finding parts for it. I am in need of a resistor (R505) and a horizontal output transistor (Q502). I paid to have a TV service come to my home and diagnose it for me, but the repair price is rediculous. The set is in extremely great condition (oak cabinet, oak facial doors), too nice to throw away.

Can any of you help me locate these two items? I've tried to get a value on the resistor and can find nothing. The transistor is also eluding me.

Please help :scratch2: ,

KR

I don't have the schematic anymore, but I know that both of those items are easily available at any electronics store once you get the generic number. I'm sure somebody here has it and can verify the numbers.

Not to be negative, but there is usually a cause for the horizontal output to blow in one of those sets. Causes include the HV divider block, or the rubber insulators on each of the deflection yokes failing, or on later models the flyback transformer causes it. And it's THOSE parts that are no longer available.

Charles

Thank you Charles for your reply, here's what I have so far.....

The R505 resistor is a 3.3K ohm/3 watt resistor....and the Q502 transistor has a part # of 2SD1556. The question I have is where are they located in the set? Is there a board I can remove and take somewhere for service? I paid a repairman to come out and troubleshoot it, and he did, but they want an additional $475 to remove and replace these two little electrical items. I realize one might have to remove old solder, or solder something in place, but if I had a schematic on it....I would try it myself. Can you help me Charles :thmbsp:

KR

I just read that you no longer have a schematic, my bad.

Thank you Charles for your reply, here's what I have so far.....

The R505 resistor is a 3.3K ohm/3 watt resistor....and the Q502 transistor has a part # of 2SD1556. The question I have is where are they located in the set? Is there a board I can remove and take somewhere for service? I paid a repairman to come out and troubleshoot it, and he did, but they want an additional $475 to remove and replace these two little electrical items. I realize one might have to remove old solder, or solder something in place, but if I had a schematic on it....I would try it myself. Can you help me Charles :thmbsp:

KR

I just read that you no longer have a schematic, my bad.

That price doesn't sound that unreasonable to me considering the work required to fix a TV like that. Those two parts are just the obvious problems. There's a very good chance that he will run into a problem that can't be repaired after spening a lot of time on it. There's a good chance that it needs a part that is no longer available. The high estimate is to make it worth his time and to discourage you from having it repaired. Even after a repair, these sets often quickly develop other problems. They are very unfriendly to work on (lots of connectors and cables that have to be removed to get to the boards, then plugged back in before you can test it). Every Mitsubishi I see seems to have dozens of leaking capacitors that must be replaced.

Well, I guess I really haven't set a defining price that will make or break this whole deal. I've paid the guy $155 for the service call and diagnosis already. The TV was free. It just seems like such a shame to throw this old beast away because it literally looks like it has been stored in a box for 20 years. It is immense is size, and immaculate in condition (other than inoperative :D )

You guys appear to be the experts here, what would you do? I've seen the set when it worked good, and the picture was pretty clear too. Should I invest $630 in this thing, or make a new entertainment center out of the cabinet?

KR

Ok, try this::

IF you have a bit of knowledge in electronic repairs-- you can replace the H-output and get the driver resistor for under $10.

When(or IF you replace these), you MUST resolder ALL of the "crispy" points around where that resistor was, and such. It is POSSIBLE that bad connections on the driver transformer have killed the output. SO, for maybe $10-15 or so, you could take a chance.

Then, before you "fire the set up", get a variac(if you can, and know how to use it) and try to "slow start" the set. this could prevent blowing the new one, if something else, like the fly, splitter, a CRT or such is bad. Like others said, mits. are known for (1) bad capacitors all over the place, (2) bad and weak CRT's, that look like shit in a few years, usually, and (3) leaky tubes, on the newer(1994-present) sets.

But you might, just get lucky. I saw a '90 m odel mits. lately, with ehavy doors, with GREAT tubes.but a LOT of bad caps!!

That sounds a lot like my mom's tv except theirs is an 1987 maufacture.It came from a condo in Bethany Beach Delaware in 2000.The original owner didn't want to repair it because it was quote"too big and 13 years old"A new high voltage bleeder cured it.The switching power supply was groaning when turned on but no blown parts .Most of the original parts aren't available but Matt Electronics was carrying replacement bleeders and yokes for those.Don't know if they still have them or not.After cleaning and adjustment it produced a beautiful picture.Don't think it saw many hours in a beach condo.Still running today and gets played 16 hours a day though they use the vcr for the tuner.The IF kept drifting when they had digital cable and they would get buzzing etc every 3 months.The day they gave up Digital Cable 2 years it wouldn't stop AFT searching no matter what I tried so it's on EXT1 with the vcr/dvd combo as the tuner.Even has the original convergence chips.Unbelievable as all those STK4273s failed after a number of years.Convergence has drifted some though.Noticeable to me but they think it looks fine so I leave it alone.This is sort of a golden year Mitsubishi since it's just beyond the yoke failures(85-86) and before the cap leakers(90 and up)or leaky tubes(94 and up)

On yours in addition to resoldering the driver transformer and the area around the transistor there is a capacitor next to it that causes the Horizontal Output Transistor to run hot and fail.It's a 1uf at 160v.I always replace it with a 250v high temp cap(105 degree).You could still have a bad flyback,Hv bleeder or yoke.The problem with gambling a lot of money getting someone else to fix it is you may not get as lucky as my mom and the set has weak picture tubes and end up with a crappy picture.That is one pretty cabinet on that tv though.My mom loves the fact that there's plenty of room to put her nick nacks and pictures.That thing looks huge in their tiny mobile home living room.Takes up a whole wall.They love it but my stepfather is realistic to keep on the lookout for a newer one in case a CRT goes or some NLA part goes.He says he'll make something else out of the cabinet since he's a woodwooker.To nice to throw away.

I know this sounds callous, but I say not to fool with it. That is the newer set with the strong possiblity of a bad flyback transformer since you sad it uses the 2SD1556.

Andy is right about the tech giving that price to discourage repair, because it is VERY common to spend huge amouts of time in troubleshooting and replacing small parts only to find the a NLA part is at root cause. It is sad, and definitely wasteful, but Mitsubishi decided not to support any TV over about 3 years old for parts! I don't know how they think this will keep customer loyalty, but that's their position. I wish I could say something more uplifting, but I wouldn't put any more $ into it...

Charles

Andy is right about the tech giving that price to discourage repair, because it is VERY common to spend huge amouts of time in troubleshooting and replacing small parts only to find the a NLA part is at root cause. It is sad, and definitely wasteful, but Mitsubishi decided not to support any TV over about 3 years old for parts!

You know, this question is a little off-topic, but I've noticed several of the manufacturers are starting to adopt this policy, not just for TV's, but also for other electronics like broadcast equipment. Is there any possibility of having a part manufactured for a piece of equipment that can't be replaced?

I know that they often keep their equipment as secret as possible these days, but if you took it as a black box and replicated functionality without duplicating the internal design. And of course had a lot of money to throw at it, could it be done?

David

I have no knowlege of any sort when it comes to this type of repair. I have taken a basic electrical course that covered transistors, capacitors, series and parallel circuits, voltage drops, etc....but nothing this indepth. I have decided to repair it, only because of the aesthetic condition of the set, and i'm just that kind of guy. You guys are a wealth of knowlege, and I hope to learn what I can from you. I'll post details of the repair. thanks,

KR

go for it, hands on experience is the best you can get. you can read for years and not get the experience that hands on can provide you. mabey it will turn :sigh: out great for you. steve