TC-RM251S monitor chassis problem

Paiku

Crazed MVS Addict
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Jun 14, 2005
Posts
141
So, months back the flyback transformer in my mvs-u4 started sending out archs.

Recently I found this replacement (http://www.ebay.com/itm/TOEI-FLYBACK-TC-RM251S-TC-RM29J-USED-IN-CANDY-CABS-/380431411451?pt=LH_DefaultDomain_0&hash=item58937aa8fb So I bought that and had the old one replaced
I noticed however there was one of the two pins next to the circular row of pins tha was was missing on the new transformer.
See pic* No clue if that has anything to do with the current issue I'm getting.
pig_saknas_zps02d8d96f.jpg

Anyway so I've plugged the chassis back and now I'm getting this mess along with a very hi-frequency sound from the monitor.
Game sounds seems to work no problem.
2013-10-09145626_zpsf1651604.jpg


I'm completely clueless and lack the knowledge. Tried looking for colds under the pcb, but things doesn't "seem" too bad.
I've fiddled around long enough with this now and could definitely use some proper :help:
 
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max 330 mega

The Almighty Bunghole
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Dec 14, 2004
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4,300
tried dialing in the 2 knobs on the flyback? also, high pitch noise means the flyback is working. it emits a high pitch noise... may be higher than usual because it is dialed up too high on one of the knobs? also the monitor has nothing to do with the speakers or the mother board, so yes you will still hear all the typical game noises. it looks as if the monitor cannot find sync. you sure youve got everything plugged back into the monitor chassis?
 

Nerdygrrl

Krauser's Shoe Shiner
Joined
Jul 24, 2011
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232
That looks like a sync issue. IIRC I am pretty sure there is a 24K and a 15K "plugs" near the flyback on that chassis make sure you are plugged in/set to the right frequency. I think this is the right photo.



 

Paiku

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Max 330 mega: I've turned the two knobs on the flyback but doesn't seem to affect the high pitch noise. Also pretty sure everything is correctly plugged back, been plugging it on and off several times now.

Nerdygrrl: Thank you for the pictures. I've tried both of these "plugs" but noone of them fixes the scrambled picture.



Thanks for the replies.
 

Nerdygrrl

Krauser's Shoe Shiner
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Jul 24, 2011
Posts
232
Max 330 mega: I've turned the two knobs on the flyback but doesn't seem to affect the high pitch noise. Also pretty sure everything is correctly plugged back, been plugging it on and off several times now.

Nerdygrrl: Thank you for the pictures. I've tried both of these "plugs" but noone of them fixes the scrambled picture.



Thanks for the replies.

Hmmm, maybe I gave you the wrong location. I no longer have my U4, I'll go back over and look at my photos and see if any provide better detail..

Do you see a set of jumpers labled with the above mentioned frequencies? They should be next to one another.
 
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Paiku

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141
Appreciate all your help :)

I can't see any frequency label in the area.
2013-10-20 15.01.54.jpg

...
What does the H-freq pot do? Althou that one is glued in place.
 

Paiku

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Jun 14, 2005
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141
So... bumping thread once again since I decided to try and get this fixed.

I got rid of the glue on the h-freq pot and the b+ pot and fiddled around. After some adjusting of these pots + h-hold I'm finally having some good progress.

However as can be seen I'm having some odd issues still. It almost looks like the picture overlaps itself showing a large block of dark/streached out graphics. I've tried to do small adjustments but can't get rid of it without losing sync.

My first guess is this needs new caps? Any ideas?

2013-12-09 19.14.06.jpg
 
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