Black Screen with 5V mod on MV-1FZS

Relo

n00b
Joined
Mar 14, 2015
Posts
19
I'm getting a black screen on my MV-1FZS that I just tried to mod with the 5V mod. Even a 10A 5V line gives a black screen so I at least know it isn't the PSU. Beyond that it seems to work fine when I run it with 12V.

So my best guess is that I missed something and can't seem to figure out what. Looking at the guide on Jamma Nation I believe I did everything.

My mod:
https://imgur.com/a/ZBSgn1L
(I checked the trace with the multimeter to confirm it's disconnected)
 

Xian Xi

JammaNationX,
15 Year Member
Joined
Dec 1, 2005
Posts
27,748
I don’t see the pic with the trace. What voltage were you getting on the 5v line? And was the PCB fully working prior to the mod?
 
Last edited:

Relo

n00b
Joined
Mar 14, 2015
Posts
19
Second pic has the cut trace, looks like a scratch. It's next to the Cap that's next to the opamp.

4.98V on the 5V line.

PCB did work fully before the mod, and still works fine if I power it like I did previously (though a super gun with a PC PSU or an Arcade PSU).
 

Xian Xi

JammaNationX,
15 Year Member
Joined
Dec 1, 2005
Posts
27,748
Only thing I see wrong is your LED is backwards. I'm not sure if that would cause issues but depends on the reverse voltage for the LED, it could be shorting it out.
 

Relo

n00b
Joined
Mar 14, 2015
Posts
19
LED was indeed reversed, I noticed that one as well as it didn't light up. Have since reversed it, it now shines but beyond that it still has the exact same symptoms.

Maybe the point I give the 5V to is wrong? Seeing as there is no mention of that in a guide. I applied to to the 5V and ground pads above the power-amp. And using the Arcade PSU gives the same results if I simply not use the 12V line.
 

DaisyAge

Galford's Armourer
Joined
Jun 10, 2018
Posts
457
Give the 5v to the Jamma edge or the vias behind the edge and see if that helps. I tried booting a board from the same points as you but it didn't work out. Different issue for me but its worth a shot.
 

Relo

n00b
Joined
Mar 14, 2015
Posts
19
Sadly no change... Granted I didn't expect a change as the Jamma connectors and the spots have continuity. But thanks for the suggestions.
 

DaisyAge

Galford's Armourer
Joined
Jun 10, 2018
Posts
457
From the JNX tutorial: " Keep in mind that if you supply the FZ with +12v after doing this mod you will have a scrambled picture so use only +5v"
The fact that it only works with 12v makes me think you didn't do the mod correctly or there is another step for this board.
Edit: Do you get any audio with a game inserted?
 

Relo

n00b
Joined
Mar 14, 2015
Posts
19
That is what I was thinking. This suggested to me I am simply overlooked a step or did one wrong in the tutorial https://retrostuff.org/2018/05/20/neo-geo-mv1fzs-5v-stereo-mod/

Yes! Audio does work normally I just get a black screen. But just over the stereomod (not surprisingly), which currently is just going to a headphone jack.
Based purely on the sound everything seems to work fine except for the screen output, as I can hear coin input sounds and sounds I expect when pressing buttons.
 

Xian Xi

JammaNationX,
15 Year Member
Joined
Dec 1, 2005
Posts
27,748
How is your video connected? Can you shows pics of everything connected?
 

Relo

n00b
Joined
Mar 14, 2015
Posts
19
https://imgur.com/a/5LE0ZYW

The arcade PSU powers the MVS fine if I apply both 12V and 5V, but without it black screen. And it says the 5V line is 10A
The wall wart I use is sadly hard to open and don't want to destroy it (one of those without screws), but says it's 3A

BTW who changed anything to 1A?
 

DaisyAge

Galford's Armourer
Joined
Jun 10, 2018
Posts
457
https://imgur.com/a/5LE0ZYW

The arcade PSU powers the MVS fine if I apply both 12V and 5V, but without it black screen. And it says the 5V line is 10A
The wall wart I use is sadly hard to open and don't want to destroy it (one of those without screws), but says it's 3A

BTW who changed anything to 1A?

Oh shit I mixed up my threads sorry lmao, had another one open in a different tab.
 

Relo

n00b
Joined
Mar 14, 2015
Posts
19
Tiny update, tried using a LM2577 DC/DC Step-up converter, but got a garbled screen and has trouble staying on the first few seconds.
 
Last edited:

rosewood

n00b
Joined
Apr 9, 2016
Posts
1
Thanks for your message.

I didn't do anything special and just followed the tutorial from the link and it worked right away. (http://www.mmmonkey.co.uk/consolised-mvs-cmvs-conversion-one-slot-mv-1fz/ - MV-1FZ 5V Only Mod)
It's probably a short circuit somewhere in the area where you removed or added something.
Test it with disabled audio amp (disconnect GND and +5 V from the add-on).
Also, test it with the super gun and only connect the arcade PSU to the +5 V terminals, if possible.
 

Relo

n00b
Joined
Mar 14, 2015
Posts
19
I think I might have solved the issue! Nothing wrong with the mod possibly, or the board. It looks like my supergun requires 12V to function... I just desoldered the 12V pin from the jamma connector on the supergun and supplied it with 12V, and powering the board with my wallwart and it works great! It might also explain why I did get normal audio from the board with the black screen. Also, as expected, I don't get any audio though the SCART cable on my supergun anymore now, which I did before.

Have mailed the guys that sold me the supergun to be sure, but I think it's solved!
 
Last edited:

DaisyAge

Galford's Armourer
Joined
Jun 10, 2018
Posts
457
Actually that makes a lot of sense since this supergun is supposed to work for multiple JAMMA boards. Hope that's it!
 
Top