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Bootleg C&D board not syncing to PVM

aha2940

aha2940

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Hi guys

I have a bootleg Cadillacs & Dinosaurs board that when played through my supergun on my PVM, will not sync. It shows the image rolling and skewed to the right and the PVM says "NO SYNC". Colors seem OK, though. I know the supergun and PVM work fine (tested with CPS1, CPS2, atomiswave, PGM and MVS) and I also know the boot C&D works fine, because when connected through a gonbes 8200 adapter, it displays image fine. Now the question: What can be happening for the PVM not to use the board's sync signal? any idea if it is fixable?

Thanks!!
 
It might be a grounding issue. Many bootlegs don't wire up the video ground to the jamma edge. Your supergun's video buffer might be expecting that pin to be connected, whereas with other connection means (linke the gonbes) you are implicitly using the PSU's grounding for video.
 
Thanks for the suggestion, but I checked the board and the video ground (pin 14 on the parts side) is connected to the board's ground properly. Any other ideas? I thought maybe adding a sync cleaner could do the trick, but I do not know if PVMs require sync cleaners or not.

Thanks!!
 
i have a similar issue so I'm interested in your findings..

in my case I have a Rygar boot that syncs ok with my Jamma cab but not to a Sony BVM + RGBs Supergun.

That's quite inconvenient since my Jamma cab is tate'd :(
 
aha2940 said:
Thanks for the suggestion, but I checked the board and the video ground (pin 14 on the parts side) is connected to the board's ground properly. Any other ideas? I thought maybe adding a sync cleaner could do the trick, but I do not know if PVMs require sync cleaners or not.

Thanks!!
Click to expand...
Ok, what kind of output does your supergun have? composite? s-video? YUV? RGBs? RGB-SoG?
 
Asayuki said:
aha2940 said:
Thanks for the suggestion, but I checked the board and the video ground (pin 14 on the parts side) is connected to the board's ground properly. Any other ideas? I thought maybe adding a sync cleaner could do the trick, but I do not know if PVMs require sync cleaners or not.

Thanks!!
Click to expand...
Ok, what kind of output does your supergun have? composite? s-video? YUV? RGBs? RGB-SoG?
Click to expand...
It's a HAS supergun, made by RGB, outputting RGB signal to the PVM monitor through the PVM's BNC inputs.
 
I had a similar problem with mortal kombat boards on a pvm and HAS. MKs have an odd refresh rate. I don't know if that boot board or game has an odd refresh rate also, but I was able to solve it by going into the pvm menus and adjusting the Vhold settings manually. It only took a couple taps and it stabilized.

That thread with instructions <--link
 
ekorz said:
I had a similar problem with mortal kombat boards on a pvm and HAS. MKs have an odd refresh rate. I don't know if that boot board or game has an odd refresh rate also, but I was able to solve it by going into the pvm menus and adjusting the Vhold settings manually. It only took a couple taps and it stabilized.

That thread with instructions <--link
Click to expand...
Hmmm...nice tip, ekorz, thanks. I have no idea which refresh rate this bootleg board uses (how do I know?) however I have tested this same setup with my Mortal kombat 2 and Mortal Kombat 3 boards, they both show image fine. Also, notice that the monitor says "NO SYNC" when using the boot board...can v-hold fix this?

Anyway, will try and report back.
 
hm yeah I don't think I ever saw No Sync when I had my issue. Worth a try anyway, may end something else in the advanced menus can help.
 
This might sound crazy but I had a similar issue with a Double Dragon game. I put a 220uf cap on the sync signal wire (negative toward the PVM, positive toward the PCB) and it straightened it out.
 
I have the same problem with Salior moon and Battletoads on my bvm. UMK3 worked fine for it.
 
Does your Supergun have the option of adjusting the sync rate?

Most of them I've seen have an adjustment pot for that which you wouldn't generally mess with, but if that's the issue then that might solve it

Could also be a weak signal which can be solved as mentioned by someone else by adding a capacitor
 
ekorz said:
hm yeah I don't think I ever saw No Sync when I had my issue. Worth a try anyway, may end something else in the advanced menus can help.
Click to expand...
The PVM has a gazillion options, most of which I do not even understand, so I do not want to move them randomly. I tried changing V-hold, but the issue persists.


skate323k137 said:
This might sound crazy but I had a similar issue with a Double Dragon game. I put a 220uf cap on the sync signal wire (negative toward the PVM, positive toward the PCB) and it straightened it out.
Click to expand...
So, I would have to break the sync line on the board and join it again using a cap (so I don't have to mod the cable, which works perfect with 6 or 7 other boards). That sounds possible, I guess, but will have to take a look at the way sync is obtained on the board, to know the place to solder.


xodaraP said:
Does your Supergun have the option of adjusting the sync rate?

Most of them I've seen have an adjustment pot for that which you wouldn't generally mess with, but if that's the issue then that might solve it

Could also be a weak signal which can be solved as mentioned by someone else by adding a capacitor
Click to expand...
My Supergun does not seem to have a way to change the sync rate. Only pot I see is for changing the sound volume, and two buttons which are Test and Service, nothing else.

Thanks guys!!
 
Don't worry about goofing up the pvm settings. You can adjust any and all, just don't write the settings unless you fixed it. There are a couple different places to adjust vhold if I recall. Try them all! I probably toggled them all up and down to see what they did, then just exited to restore everything. That way I could go back in and just adjust the one setting that mattered.
 
ekorz said:
Don't worry about goofing up the pvm settings. You can adjust any and all, just don't write the settings unless you fixed it. There are a couple different places to adjust vhold if I recall. Try them all! I probably toggled them all up and down to see what they did, then just exited to restore everything. That way I could go back in and just adjust the one setting that mattered.
Click to expand...
My PVM seems to save the settings automatically, I have never had to do anything for it to save, I just enter the menu, change settings, exit the menu, it saves.
 
aha2940 said:
So, I would have to break the sync line on the board and join it again using a cap (so I don't have to mod the cable, which works perfect with 6 or 7 other boards). That sounds possible, I guess, but will have to take a look at the way sync is obtained on the board, to know the place to solder
Click to expand...
I wouldn't do that until/unless you know it fixes the problem.

What I made myself was few jumper cables with various resistor/cap in them. These help a lot with console signals but occasionally I use them with arcade PCB for troubleshooting. The 3 I use the most are :

220 ohm resistor
220 uf cap
220 uf cap and 75 ohm resistor

Most of my stuff I use RCA->BNC adapters so I just make quick RCA cables that I can jump inline if that makes sense. You could buy a short BNC male to female cable, and splice in a cap on the positive (Center) wire. Leave the shielding intact for your grounding.


Also... do you observe any change in behaviour if you unplug just the sync cable? What model no. PVM do you have?
 
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