MVS MV1-FS / Hardware Test - Color Bars issue - Fixed

Jontox

Quiz Detective
Joined
Jul 19, 2016
Posts
89
Hi All,

Best wishes and for sure good health for 2021 during this pandemic time!

I'm not an Neogeo expert, nor an electrician or hardware engineer so bare with me please.

A few years back I decided to consolize on my own a MVS slot, this was realize thanks to Xian Xi tutorials available (thanks a lot man), then mikejmoffitt released on that same time his NEOVGA and I decided to do everything in one step.

Consolization and NEOVGA went great and everything was functional, but I was not satisfied with the solders done. I then decided on December 2020 to redo everything with time and dedication.

Now everything is still working and well soldered and organized, and most of all I'm satisfied with the result.

Slot is working and playing great with all games, the picture seemed good to me on a LCD screen, I though it was a good time to go through the Hardware Test menu (usually skipped by the Unibios).

Then I observed slight issues in the color bars test.
Please have a look on the picture linked, I am all hears ! :glee:

I found out that Xian Xi experienced a similar issue there http://www.neo-geo.com/forums/showthread.php?234580-MV1A-Display-Problem
shall I verify all resistors somewhere ?

Thanks a lot in advance for any suggestion











 
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DaisyAge

Galford's Armourer
Joined
Jun 10, 2018
Posts
457
God damn as a fan of cable management I gotta say this is by far the most impressive CMVS wiring I've ever seen. From one consolizer to another, congratulations. As for the resistor values try sending Big Bear a PM, he has helped me with resistor values in the past, he's a great guy to ask. Looks like only the green resistor ladder is affected so that at least narrows down what needs to be replaced. It's not a terrible idea to replace all of them while you're there. Good luck!
 

Jontox

Quiz Detective
Joined
Jul 19, 2016
Posts
89
God damn as a fan of cable management I gotta say this is by far the most impressive CMVS wiring I've ever seen. From one consolizer to another, congratulations. As for the resistor values try sending Big Bear a PM, he has helped me with resistor values in the past, he's a great guy to ask. Looks like only the green resistor ladder is affected so that at least narrows down what needs to be replaced. It's not a terrible idea to replace all of them while you're there. Good luck!

Thanks DasiyAge for the nice words.

My point is are all these resistors part of the DAC (Digital-to-Analog Converter) as if this the case, I'm not using the RGB JAMMA or any RGB analog signal points on the PCB but directly taking the digital RGB signal from the two 74LS273 latches as per NEOVGA install instructions.
Are these resistors still part of the problem or are these only used during digital to analog conversion ?

If it is the latter, my issue shall be linked to the 74LS273 directly or my soldering points for the Green signal on the NEOVGA ?

RGB colors seems obtained from 5 points respectively 0,1, 2, 3, 4 on the 74LS273.
Does anyone know which point is responsible for which part of the color bar hardware test screen ?



N.B.: All image are thumbnail, higher resolution is obtained by downloading it

Many thanks in advance
 
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mikejmoffitt

Mickey's Coach
Joined
Feb 6, 2014
Posts
578
It looks to me like green bit 1 (second from the lowest, 0) is missing or stuck somehow. Double check the wiring of the lower green bits and make sure those are doing okay. Your wiring is very neat.

EDIT: On second review, it might just be that the green bit is being grounded out by the slightly long exposed wire near the NeoVGA PCB. Check for continuity with ground, and make sure it isn't shorted there.
 
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Jontox

Quiz Detective
Joined
Jul 19, 2016
Posts
89
It looks to me like green bit 1 (second from the lowest, 0) is missing or stuck somehow. Double check the wiring of the lower green bits and make sure those are doing okay. Your wiring is very neat.

EDIT: On second review, it might just be that the green bit is being grounded out by the slightly long exposed wire near the NeoVGA PCB. Check for continuity with ground, and make sure it isn't shorted there.

Thanks a lot Mike, that was it.

The culprit was precisely bit 2 from the green color. The wire was shorted by the NeoVGA PCB ground border which had some solder on it




Now the result of the hardware test color bars




And for the Fatal Fury fans out there, some kicking ass action in perfect colors




One last pic, some MVS slot porn... this community here is amazing and thanks to all his members and their contributions (advise, tutorials, software and hardware) that is here what can be achieved by a Neogeo fan on his own.



Cheers all
 
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