[MVS] weird video problem

[supergoose]

last week, i got a few mvs boards in the mail. all the shape of the MV1FZ but some of those boards are MV1A variants. most worked well when i tested them but i have problems with two MV1ACH and one MV1AX board. while one of those three boards is in a terrible physical condition (leaking battery, filth & repaired traces), all three show the same problem. the other two boards are in a decent condition and not too dirty, btw.

here's a video:



other MV1A and MV1FZ viariants work(ed) well with my supergun. none of the caps seem to be leaking. one leg of one cap is ripped off and i didn't get to repair it yet, but still ... the problem is the same with all three boards.
i'm using a sc200 psu with my supergun (5V 4A and 12V 1A, according to the label on the back of the psu).

has anyone seen something like this before and knows how to fix it?

might have to send this one back:

 

[OldTony]

This appares like syncro signal is missed, check if resistors closly to jamma connector to P terminal on jamma connector are ok it is syncro signal.

 

[HeavyMachineGoob]

That's some pretty interesting corrosion. Never seen the green kind on an MVS board before. You should try to clean up the PCB with rubbing alcohol/tooth brush or warm soapy water anyway. If there's still bad joints, try to reflow them. I find that sometimes helps to patch corrosion (if you can get the old solder to cooperate that is).

But yes, firstly you have no sync signal. Just follow from the JAMMA sync pin (Pin P) across the PCB, checking for continuity and whether any of the components are bad. Also, it's hard to tell from the video, but the picture is very blue looking. I think you're missing red and/or green.

 

[Xian Xi]

I would first deflux the board, 3M makes a very good flux remover. After that I would wash the board with soap and water using a tooth brush. Make sure you remove the battery and socketed chips before washing. Use compressed air or canned air to get water out from under the chips.

 

[distropia]

I would first deflux the board

nail paint remover?

 

[fremen]

Hi,

nail paint remover?

Acetone is very dangerous, the plastic is corroded by it.
Isopropylic alchool is ok, also ethanol.

Saludos

 

[supergoose]

i'm sure i will file a claim with ebay so that i can return the board in the pictures. that's why i can't really do much to it, atm. i paid 65€ plus postage for the board and i think that messing with it isn't worth it. the other boards don't look anywhere near as bad as the one in the pictures, though.

also, i already cleaned the working boards. here's one of them, just in case that any of you guys would like to give up smoking but need a bit more motivation:

yes, i do think that smoking is one of the most disgusting hobbies ever. uke:

 

[Xian Xi]

Next time, make sure you remove the battery first.

 

[HeavyMachineGoob]

You do know the battery still holds a charge right? Electricity + water = very bad. Some of the components connected to the battery might get shorted.

 

[supergoose]

i knew you'd say that but honestly, i cleaned about 30 boards like this and the battery never caused any problems. at first i didn't know any better but this time i didn't really care. just wanted to get rid of the smell asap.

[disclaimer]wouldn't want to advice anyone to do the same.[/disclaimer]

 

[HeavyMachineGoob]

Removing the battery before washing with water is pure common sense and scientifically sound. All electric sources should be removed before contact with water...

 

[supergoose]

My first few boards had batteries like the one in my first picture. I was new to the arcade scene and wasn't even aware that it was a battery. But yeah, i should have taken this one off ...