Build Your Own Arcade Controls Forum
Main => Monitor/Video Forum => Topic started by: msolajic on September 09, 2009, 07:46:09 am
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Hi all,
as someone said in this forum, this monitor should be a Hantarex MTC9000A (or it is a MTC9000 European model).
First thing - Jailbars. I have already ordered the capacitors needed and will replace them all on the chassis. Hopefully, this wil solve the problem. (Picture 1)
Second, it has visible retrace lines. Will the cap kit solve this, too?
Third, there is some problem with the brightness / contrast. I have tried to adjust it, but the best I can get isn't quite satisfying. I have forgotten to take a picture, but I've simulated it in a screenshot from mame. (picture 2 - regular mame screenshot, picture 3 - simulated monitor screenshot). How to get around this issue? I have also attached the pictures from the game, you can clearly see that there *IS* a big difference.
Fourth, there is some strange noise in the form of lines on the screen, it is visible even if I disconnect the game board. I don't have a clue what would cause that.
And the last one, it looks like the flyback was changed at some point. When I took the monitor apart to clean the dust from the chassis, I found out that there are some broken tracks which are directly connected to the flyback, and that some pins of the flyback aren't soldered at all (picture 5). Since the monitor is working, should I repair those tracks and solder the remaining pins of the flyback to the chassis? My grandfather always told me "If it ain't broken, don't fix it", but this really bothers me.
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I have added a annotated picture with the broken tracks and unsoldered pins. One of those tracks and two unsoldered pins are clearly a ground for the flyback. Could this cause the noise I am seeing on the screen?
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baring in mind i'm not an expert let me make an attempt at this...
the jailbars and retrace lines you have remind me more of screen being adjusted to high or sync not being quite right...so assuming you haven't tried those adjustments already that would be something to try(cap kit is always a good idea regardless though)...the screen adjust would be on the flyback and the sync knob should be clearly marked in most cases so should be able to find it...
if the screen knob is indeed adjusted too high that might help with the contrast thing...could also just be a mame setting somewhere...i don't use mame so can't help too much there...
as for the traces, etc on the flyback...I have several boards whose flybacks have points that are not soldered, so until i looked at a schematic or heard from someone more knowledgeable than myself, I would just leave them unsoldered for now...and the traces you should be able to test continuity with a multimeter to see if they need any work...I have lots of scratches like those on some of my boards that don't actually cut the traces...
again, I'm no expert and these are just opinions off the top of my head...but maybe gives you a couple safe things to play with while you wait for one of the experts to chime in ;)
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top solder point is for the xformer core . usually not a critical solder point .
the next connection needs to be resoldered. looks like this ground point has been arcing .
a gentle scratch is usually of little consequence . unless arcing is observed .
deep scratches breaking the trace, or trace cracks need to be patched .
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Thanks for the replies.
the jailbars and retrace lines you have remind me more of screen being adjusted to high or sync not being quite right...so assuming you haven't tried those adjustments already that would be something to try.....if the screen knob is indeed adjusted too high that might help with the contrast thing...
If I turn down the screen control the picture gets really dark. Hardly visible. I have adjusted all of the controls (contrast, brightness, RGB gain & cutoff) to get the best image.
could also just be a mame setting somewhere...i don't use mame so can't help too much there...
That's a Silkworm original PCB, not MAME. MAME was just used to illustrate what is going on.
the traces you should be able to test continuity with a multimeter to see if they need any work...
a gentle scratch is usually of little consequence . unless arcing is observed .
deep scratches breaking the trace, or trace cracks need to be patched .
On the picture it looks like a scratch, bit infact it is broken. There is no continuity on those two traces. That will be repaired.
top solder point is for the xformer core . usually not a critical solder point .
the next connection needs to be resoldered. looks like this ground point has been arcing .
OK, will do that too.
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Hey, I'm afraid these are the best pictures I could get for you of my MTC9000A's flyback as it's installed/working in one of my machines at the moment, these are from photographs of past repairs
It was replaced at some point in the past by a sloppy technician thus the awful soldering and a resoldered trace, but all the pins seem to be soldered in and it's working just fine. I intend to replace this myself at some point!
If you need any more advice on this or replacement flyback, swallowamusements.co.uk do a lot of Hantarex repair and parts and seem to have some info on the MTC9000A so maybe give them an email :)
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Amazing! I can't believe that monitor is still functional with that kind of solder work.
Then again I once had a K7000 that displayed symptoms of a dead smoothing cap. The cap was bad for sure, but as I was checking out the rest of the chassis I noted that the red wire on the yoke connector wasn't even soldered on. Okay, maybe a thread. It had obviously been that way for a very long time. Replaced the smoothing cap, hit the flyback and yoke joints with the solder, and viola! Beautiful picture.