MV1FZ video sync issue

lions3

lions3

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Hey, just picked up a MV-1FZ to drop in my NAC. The only issue is the video is flickering. I'm assuming it's a sync issue but i'm not sure if there's an easy fix or not. Any ideas?

Also I tested a CPS2 game just to make sure my monitor wasn't the problem.



Here's 2 pics of the board without the plastic on it. The only problem I've seen while looking it over is 2 broken connections on the bottom of the board (marked in red). I'm not sure if they're a big deal or not. Hell I don't know if those are tiny resistors or what. Hopefully google will find me a diagram showing what they are.

85359160.jpg


25343102.jpg
 
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Xian Xi

Xian Xi

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Hmm, the last person that had a sync issue with an Fz in an NAC said to put a 1k pot on the sync line. You can try that.
 
lions3

lions3

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Xian Xi said:
Hmm, the last person that had a sync issue with an Fz in an NAC said to put a 1k pot on the sync line. You can try that.
Click to expand...

Is there a way I can add the pot without cutting my harness or the board? The only thing I can think of is making a jamma extender and adding the pot to that. (Hmmm... I wonder if I have the spare parts sitting around)

Also, on a side note, I completely forgot about an old supergun. The MVS ran fine on it. So yeah, it's got to be an issue with the NAC and the MVS not getting along.
 
mjs256

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Some displays have different requirements for sync voltages and frequencies. In particular, some (mostly newer) displays are very picky about the vertical refresh frequency being *exactly* 60.000Hz. If it is a voltage issue then you may need to add an inverter, buffer, or op-amp to boost and/or invert the sync signal. Perhaps an LM1881N would clean it up enough for the display to "like it" enough to sync properly. If it is a problem with the frequency being a bit off then there is not that much you can do other than check the 32.768 and 24 MHz crystals on the MVS to make sure they are accurate, and you would probably need an oscilliscope to do that. I once had a Combatribes PCB that would not sync with my display because the sync frequency was like 59.1 Hz and the only way I could make it work was to use a RGB to S-video adapter and connect it to a S-video display instead. Apparently the convertor and S-video display were not as picky as my usual display device.
 
lions3

lions3

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mjs256 said:
Some displays have different requirements for sync voltages and frequencies. In particular, some (mostly newer) displays are very picky about the vertical refresh frequency being *exactly* 60.000Hz. If it is a voltage issue then you may need to add an inverter, buffer, or op-amp to boost and/or invert the sync signal. Perhaps an LM1881N would clean it up enough for the display to "like it" enough to sync properly. If it is a problem with the frequency being a bit off then there is not that much you can do other than check the 32.768 and 24 MHz crystals on the MVS to make sure they are accurate, and you would probably need an oscilliscope to do that. I once had a Combatribes PCB that would not sync with my display because the sync frequency was like 59.1 Hz and the only way I could make it work was to use a RGB to S-video adapter and connect it to a S-video display instead. Apparently the convertor and S-video display were not as picky as my usual display device.
Click to expand...

Wow, thanks for the write up. I guess I can only hope it's a voltage issue and not frequency. Cus that sounds way past my abilities.

On a side note, is there any reason this FZ is having problems when this same NAC was able to run a MV1C just fine? Additionally, would the fact that someone converted the NAC monitor to a Tri Sync Wei-Ya chassis have any effect?

Also I'm half tempted just to see if anyone wants to trade a different one slot MVS board for it. lol
 
lions3

lions3

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UPDATE: well I guess it's a frequency issue between the MVS and my monitor. Because last night I adding a pot to video sync and it didn't help. So now i'll be moving this to the WTT/WTS thread.
 
Xian Xi

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If you have a multimeter check the resistor values of the 2 resistors on the sync line. It should be 100ohm and 470ohm.
 
mjs256

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The best way to figure out what is going on is to use an oscilliscope to look at the sync output waveform. Apart from that you could build a circuit with transistors, zener diodes, resistors, timers, LED indicators and such to figure out the voltage extremes and frequency, but that would be a lot of work.
 
lions3

lions3

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Xian Xi said:
If you have a multimeter check the resistor values of the 2 resistors on the sync line. It should be 100ohm and 470ohm.
Click to expand...
I'll take a look tonight. Are these the small resistors next to the P on the jamma output?
mjs256 said:
The best way to figure out what is going on is to use an oscilliscope to look at the sync output waveform. Apart from that you could build a circuit with transistors, zener diodes, resistors, timers, LED indicators and such to figure out the voltage extremes and frequency, but that would be a lot of work.
Click to expand...
Oscilliscope? I'm afraid that's not in my pile of available electronics. Kinda wish it was. They're very cool. If a few resistors or a sync cleaner don't do the trick i'm afraid I'll either have to sell it or give to my brother with a supergun.
 
lions3

lions3

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well it's not the 2 resistors. Both seem to read just fine (97.2ohm and 471ohm).
 
lions3

lions3

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UPDATE: purchased a JROK sync cleaner from Xian Xi and that fixed my MV1FZ!! Happy early Christmas to me! lol
 
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