Author Topic: Anyone good at repairing monitors?  (Read 429 times)

pdiggitydogg

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Anyone good at repairing monitors?
« on: November 13, 2014, 02:13:48 AM »
As mentioned in another thread, I have an old Mitsubishi am-2752a monitor that needs some repairs.
The short of it is it is only giving off 6v from the power supply, according to my local repair guy (who I am about to give up on).
I cannot get a service manual for it (can't find one!) nor do I have schematics...
What do I do, fellas? I want this thing to work. Its quite good...
Can anyone walk me through fixing it? I am not interested in dying from CRT voltage...

BigusSchmuck

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Re: Anyone good at repairing monitors?
« Reply #1 on: November 13, 2014, 12:16:01 PM »
I'm assuming you mean pc monitor? There is a bunch at value village etc for dirt cheap $5 I think? Might be worth it just to go that route...

cjameslv

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Re: Anyone good at repairing monitors?
« Reply #2 on: November 13, 2014, 12:41:22 PM »
I'm assuming you mean pc monitor? There is a bunch at value village etc for dirt cheap $5 I think? Might be worth it just to go that route...

It's not a pc monitor.

As mentioned in another thread, I have an old Mitsubishi am-2752a monitor that needs some repairs.
The short of it is it is only giving off 6v from the power supply, according to my local repair guy (who I am about to give up on).
I cannot get a service manual for it (can't find one!) nor do I have schematics...
What do I do, fellas? I want this thing to work. Its quite good...
Can anyone walk me through fixing it? I am not interested in dying from CRT voltage...

Well the only 29" i knew of that has good documentation is the elusive nec xm2960. You just dont see many 29" broadcast monitors around much anymore. Might look into the sony pvm/bvm but i only see 20" models floating around. Sad to see nice sets like that dying off.
« Last Edit: November 13, 2014, 12:46:55 PM by cjameslv »

pdiggitydogg

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Re: Anyone good at repairing monitors?
« Reply #3 on: November 13, 2014, 02:39:51 PM »
Correctomundo. Its a 27" screen presentation monitor, with multi sync, composite, s video, RGB BNC, and VGA Excellent sound too, BTW.
It's the only monitor like this I've ever seen in person.
I have a 13" pvm with s video too, but this thing dwarfed that in every which way. I have a 27 Trinitron too, but it doesn't do RGB directly and I've had trouble with the yuv converters.
Ugh. I so want this fixed!

cjameslv

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Re: Anyone good at repairing monitors?
« Reply #4 on: November 13, 2014, 03:52:55 PM »
Correctomundo. Its a 27" screen presentation monitor, with multi sync, composite, s video, RGB BNC, and VGA Excellent sound too, BTW.
It's the only monitor like this I've ever seen in person.
I have a 13" pvm with s video too, but this thing dwarfed that in every which way. I have a 27 Trinitron too, but it doesn't do RGB directly and I've had trouble with the yuv converters.
Ugh. I so want this fixed!

Yeah lol gotta luv crt sizes, 29" with 27" viewable, wonder why they dont just size them by the viewable and ditch the actual tube size? Ya most consumer tvs don't do rgb in the states, but usually will have component/dvd inputs that work pretty good for sd tvs.

thesteve

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Re: Anyone good at repairing monitors?
« Reply #5 on: November 13, 2014, 04:17:27 PM »
i fix TVs/monitors
been working on them since the mid 80s
would need a bit more info then you have given so far
most sets i never see a schematic or manual

pdiggitydogg

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Re: Anyone good at repairing monitors?
« Reply #6 on: November 13, 2014, 09:34:32 PM »
If I were to get the unit back do you think you could walk me through checking parts?? I own a multimeter and can easily check traces, but I have a feeling there is a lot if stuff inside this beast.

thesteve

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Re: Anyone good at repairing monitors?
« Reply #7 on: November 14, 2014, 07:40:10 AM »
i could help, but i dont know how far we would get
often its what you notice while looking for something else
there are standard failures as well, but what they are depends on the circuit design
you said its only got 6V off the supply, that is an odd failure as most run about 130V as their main supply to the H-Out transistor.
shorted parts generally short to 0V
the story of the failure is always helpful as to repair we must roll back its death

pdiggitydogg

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Re: Anyone good at repairing monitors?
« Reply #8 on: November 14, 2014, 09:14:41 AM »
My guy said he replaced a couple "parts"...

Here's the story of its demise:
Day 1 of receiving the monitor, I bring it home and boot it up after many years of it sitting in a dry room, on a rolling cart, high off the ground.  I let it warm up for awhile while I reset the adjustment knobs to zero/middle.  This monitor has no on-screen display, just black until it receives a signal.  I play several minutes worth of a game, on s-video and check the composite input, too.  I leave the monitor on and eat dinner, afterward returning to some more gaming - maybe two hours.  Power off, it's bed time.
Day two, I come home and decide to play some more games.  I turn the unit on, let it sit for a minute and boot up the same console as the previous day.  No picture.  Audio works fine.  I check my inputs and still nothing.  Try the same console and wiring on another monitor and it works fine.
I reconnect the console to the Mitsubishi and cycle the power.
For a split second, there is video before the screen goes black - audio still works fine.
I cycle the power again out of curiosity and this time the picture flashes but the audio is very low (even at max volume).
Realizing something is borked, I turn it off for awhile before trying again later...  No picture flash, still super quiet audio.

And that's all I know...  It worked perfectly fine, without color distortion, brightness issues, or otherwise on day one.

In all honesty, I really feel like I should pick it up again, from the repair guy.  If for no other reason than he isn't able to fix it and someone else (maybe me with some help?) can.

thesteve

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Re: Anyone good at repairing monitors?
« Reply #9 on: November 14, 2014, 01:17:41 PM »
sound like a plan
the lost pic isnt unheard of
did the screen have static cling (not seen, but felt) when powered up the first time no pic?

pdiggitydogg

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Re: Anyone good at repairing monitors?
« Reply #10 on: November 16, 2014, 06:32:14 AM »
Oh that's something I hadn't thought of...
I want to say there was no static on the day it had no picture. I remember it was quite strong on the first day of use. Very noticeable...

thesteve

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Re: Anyone good at repairing monitors?
« Reply #11 on: November 16, 2014, 07:07:13 AM »
so the high voltage circuit dropped out first
still need to know how its built

pdiggitydogg

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Re: Anyone good at repairing monitors?
« Reply #12 on: November 16, 2014, 09:33:30 AM »
I am going to contact the repair guy this week and arrange a day to pick it up.  It will be a couple days, since I get out of work late the next few days.  I'll post pictures when I get it back and opened up.
I know there is a separate board for damn near everything inside, due to its age.

thesteve

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Re: Anyone good at repairing monitors?
« Reply #13 on: November 16, 2014, 12:38:57 PM »
age has little to do with it

PunkicCyborg

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Re: Anyone good at repairing monitors?
« Reply #14 on: November 17, 2014, 03:51:24 AM »
Hopefully you can resurrect it, that is a badass monitor worth saving.
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