[SOLVED] Problem with RGB on multiple monitors/boards

[massimiliano]

Hi team,

I'm having an issue with a Mak Strike amd RGB connection..

First of all,I have to mention I removed the SCART connector (as I do not have any TV/monitor with scart here in the US)

Tha's the only mod I did, I can assure you the PCB is clean and I did not ruin anything, I used a desoldering gun which worked flawlessly.

I made a cable taking R,G,B Sync and ground (checked continuity to Jamma video ground pin) and connecting them to the right pins (on both 1084s and the cabinet monitor).

Now, when I try to connect different neogeo boards (2 slots, 1 slot etc..) on different monitors (one arcade in the cabinet and a 1084s-d2 commodore) I get the same issue.

When the supergun's main switch is *off* (but PSU is connected to outlet and to MAk Strike 12v,GND,GND,+5v)) I can see a blue pattern (attach 1084s...when I connect it to the arcade monitor it starts hissing but no blue lines:/ )

When I turn the supergun on, I can see the game (so sync seems OK) but it seems missing red and I can see a blue pattern moving (this on both moniitors, attach, never mind the bank error message, with other 2 boards the game starts perfectly, same blue pattern and missing red)

The power supply is new and is giving 5.0v measured by the MAk.

..it seems strange to me, as the Mak strike is a passive element?Any idea? Maybe one of the pots is gone?

Thanks!

Edit:

tried to disconnect the rgb sync and ground wires one ofter the other and here the result:

MAk main switch off:

R,G or B wires disconnected (until I had only sync and ground), similar "blue" lines patterns ,a bit different pattern, same color
removed Sync (only ground connected) same issue as above
disconnected the cable, no issue (obv)

I recall I disconnected only the video ground once (RGB and SYnc connected), and had the blue pattern anyway.

...?

 

[massimiliano]

Hi, quick update, I made a small JAMMA PCB wiring only +5, GND, GND and R,G,B,Video Ground and Sync.

Same issue.

It is not the Supergun then...

...could it be the PSU? Also, I cannot test other RGB source, but the fact that both monitors have this issues is kinda fishy... (the arcade monitor did work, I'm sure of it)

..is there a well known MVS problem with straight RGB connection?

Edit:

for what is worth, the 1084s via composite works like a charm

 

[Xian Xi]

Looks like the board itself.

 

[massimiliano]

Looks like the board itself.

I tested 4 different boards 1slot, mv-1c, 2slot and a 4 slot...same issue.. Last time I hooked them to the cab they worked fine (now Ica nnot test again on the cab but sounds a bit of stretch having 4 foulty boards with the same problem)

As mentioned, I took the pic with a MV-1C displaying that error, but with other boards the games runs just fine (but graphic seems missing red and there is this blue pattern rolling)

Edit:

Tomorrow I'll get a PC PSU at local thrift shop and rule out the PSU..

 

[aha2940]

What I see is this: You have tested several boards, all of them produce the same issue with bad image, so the problem lies in a component common to all boards. It's not the supergun (which was unlikely, since it's a passive component). It shows the same on 2 different monitors, which leads to believe that the problem is in the RGBs signal sent by the boards. Try changing the Power Supply (no idea how it could be the problem, but it seems the common factor here).

Regards.

 

[massimiliano]

What I see is this: You have tested several boards, all of them produce the same issue with bad image, so the problem lies in a component common to all boards. It's not the supergun (which was unlikely, since it's a passive component). It shows the same on 2 different monitors, which leads to believe that the problem is in the RGBs signal sent by the boards. Try changing the Power Supply (no idea how it could be the problem, but it seems the common factor here).

Regards.

Thanks, that's my conclusion as well after divide&conquer...now I realized the video cable wires are actually different from any other cable I handled before...copper is a single, thick wire...maybe it behaves as a resistor? it is shielded and all and I'm 99% sure it is for video but...

Anyway, just got a 5v PSU and a s-video cable (will strip the wires and use it for rgb)

will post results later today

 

[aha2940]

Thanks, that's my conclusion as well after divide&conquer...now I realized the video cable wires are actually different from any other cable I handled before...copper is a single, thick wire...maybe it behaves as a resistor? it is shielded and all and I'm 99% sure it is for video but...

Anyway, just got a 5v PSU and a s-video cable (will strip the wires and use it for rgb)

will post results later today

That's cool, but what puzzles me the mos is this:

When the supergun's main switch is *off* (but PSU is connected to outlet and to MAk Strike 12v,GND,GND,+5v)) I can see a blue pattern (attach 1084s...when I connect it to the arcade monitor it starts hissing but no blue lines:/ )

Because to me it does not make sense that the monitor displays any image when the supergun is off, even if power is connected to it. The monitor displaying image, would mean that the board connected to the SG is sending some signal (SG is a passive component, cannot generate any signal by itself) and if the board is sending signal, it means it's getting power from somewhere, which means the SG is not completely off (or there is some kind of interference/ground loop/alien activity). Am I missing/misunderstanding something here?

Regards.

 

[massimiliano]

That's cool, but what puzzles me the mos is this:



Because to me it does not make sense that the monitor displays any image when the supergun is off, even if power is connected to it. The monitor displaying image, would mean that the board connected to the SG is sending some signal (SG is a passive component, cannot generate any signal by itself) and if the board is sending signal, it means it's getting power from somewhere, which means the SG is not completely off (or there is some kind of interference/ground loop/alien activity). Am I missing/misunderstanding something here?

Regards.

that puzzles me as well...I'm not familiar on how they implemented the main switch, but I think it simply cuts the +5 feed, not also the ground, so if the issue is current on ground, it could still be?

using the JAMMA PCB I made, I simply plug it or not (no main switch) but I can see same issue when on...

I plugged just the cable on the monitor and there is no issue (black screen of course) ..so the cable itself is not "shorting" anything on the monitor.

 

[massimiliano]

Alright! It was the damn video cable...

I made a different one recycling a JAMMA loom and it works *great* (seriously, I'm astonished by the 1084S... and I had few cabs)

Apologies for wasting people's time, but I was sure that 5 wires cable was for video...probably it created some sort of resistance due to the copper thickness..

 

[aha2940]

Alright! It was the damn video cable...

I made a different one recycling a JAMMA loom and it works *great* (seriously, I'm astonished by the 1084S... and I had few cabs)

Apologies for wasting people's time, but I was sure that 5 wires cable was for video...probably it created some sort of resistance due to the copper thickness..

Nice you found the solution. I do not think those bands are resistance, usually resistance in a video line just dims the image, that looks more like some interference, or some cable touching other that it should not. Or both

 

[Heinz]

Good to see you have solved your issue. About the solid core cable though, it makes no difference. However there is a difference in resistance it is negligible at best between solid and stranded. I would check that cable...

 

[Xian Xi]

If all the boards look the same and it isn't the supergun, I'd think it's the PSU. Voltage might be right but current might not be.

Also check voltage on the board itself furthest from the JAMMA edge. If it's below 4.75v then those problems make sense. But it still needs to be close to 5.00v to work properly.

 

[massimiliano]

If all the boards look the same and it isn't the supergun, I'd think it's the PSU. Voltage might be right but current might not be.

Also check voltage on the board itself furthest from the JAMMA edge. If it's below 4.75v then those problems make sense. But it still needs to be close to 5.00v to work properly.

Thanks Xian, but as stated above, it turned out that the culprit was actually the damn RGB cable... I'm using the PSU right now and it has a steady 5.00 (MAK voltage display) all great ..I really don;t know what is so special about this cable, far from the copper type, everything else seems fine... (I'm gonna burn it, and release the demon trapped inside)

 

[Atro]

seriously, I'm astonished by the 1084S... and I had few cabs

The 1084's are beasts. I might get one back soon too.

 

[Xian Xi]

Thanks Xian, but as stated above, it turned out that the culprit was actually the damn RGB cable... I'm using the PSU right now and it has a steady 5.00 (MAK voltage display) all great ..I really don;t know what is so special about this cable, far from the copper type, everything else seems fine... (I'm gonna burn it, and release the demon trapped inside)

That is weird, most likely a ground loop or something else wacky. Glad you figured it out. And last thing, you're in the US now?

 

[massimiliano]

That is weird, most likely a ground loop or something else wacky. Glad you figured it out. And last thing, you're in the US now?

Yeah, definiively fishy...btw I took note of the cable brand/model, it is a Belden M 9305, here the datasheet:

http://www.belden.com/techdatas/metric/9305.pdf

it is a 4 twisted pairs, for "audio and control" meh

Yes I moved to NC couple of years ago... now got 125v, imperial system and no SCART!