Nintendo VS PCB getting hot

at1105

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I've got a Vs. MDS-05-CPU pcb with Goonies MDS-VS1-01 daughter board installed in the bottom slots (8J,8F). Played it for months with no issues. I was thinking about getting another game so I wanted to test the top slots (2J,2F) before I bought one. I moved it to those slots and powered it back on. No game, just a blank screen and the smell of something burning. I turned it off immediately. I moved Goonies back to the bottom slots and powered it back on - same thing. I couldn't find anything burned or smoking but discovered that 8E (74LS373) under the daughter card was extremely hot - hot enough to burn the skin. Any ideas of whats up?
 
I've got a Vs. MDS-05-CPU pcb with Goonies MDS-VS1-01 daughter board installed in the bottom slots (8J,8F). Played it for months with no issues. I was thinking about getting another game so I wanted to test the top slots (2J,2F) before I bought one. I moved it to those slots and powered it back on. No game, just a blank screen and the smell of something burning. I turned it off immediately. I moved Goonies back to the bottom slots and powered it back on - same thing. I couldn't find anything burned or smoking but discovered that 8E (74LS373) under the daughter card was extremely hot - hot enough to burn the skin. Any ideas of whats up?
I am assuming you have a Unisystem cab (single monitor)? Not the redtent or dual system.
You won't ever see anything on the 1-2 side of the pcb. Single monitor cabs only use the 6-8 side. The 1-2 side is for the tent or dual system. Someone did make a switcher that utilized both sides of the board, with a switch and later with a button press. But finding one of those is next to impossible.

As far as what happened to get the burning smell, not quite sure. Did you possibly install the daughtercard 1 or 2 notches off in the sockets? Maybe shorting something? Or maybe you shorted a tan disc Ceramic capacitor, because some sit close to the daughtercard.
If that IC is getting that hot, you should probably replace it and see what happens. Getting warm is common, hot means a short. It could be an internal IC short and you'll be good to go after replacement, or something might be shorting it. Then you will have to find a schematic and start searching.
 
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+1 to what joe3693 said about single versus dual monitor cabs.

IIRC side 1-1 needs to be populated. You can't just populate 1-2 w/o 1-1 being populated.

Try moving the daughter card back and see how that goes.
 
Aren't switchers faurly easy to find? I got some from Vector Labs a few years back that look great, and they seem to still be in business.

I have two VS boards in a Unisystem, both sides of both boards populated. I wanna say P2 button and left/right on the player one side switch sides of the boards and P2 plus A switch between bords. P2 Plus down on the player one side does a coin drop.

Pricey, but theyver worked great for me.
 
Aren't switchers faurly easy to find? I got some from Vector Labs a few years back that look great, and they seem to still be in business.

I have two VS boards in a Unisystem, both sides of both boards populated. I wanna say P2 button and left/right on the player one side switch sides of the boards and P2 plus A switch between bords. P2 Plus down on the player one side does a coin drop.

Pricey, but theyver worked great for me.
I'm sorry I was referring to the single board switcher made by cambridge arcade, since he said he had 1 board. Yes Vector Labs makes a 4 board switcher. I have no idea what the lead time is on that. Definitely an investment for Vector labs 4 board switcher, but those I know that have it are quite happy with it.
 
I am assuming you have a Unisystem cab (single monitor)? Not the redtent or dual system.
You won't ever see anything on the 1-2 side of the pcb. Single monitor cabs only use the 6-8 side. The 1-2 side is for the tent or dual system. Someone did make a switcher that utilized both sides of the board, with a switch and later with a button press. But finding one of those is next to impossible.

As far as what happened to get the burning smell, not quite sure. Did you possibly install the daughtercard 1 or 2 notches off in the sockets? Maybe shorting something? Or maybe you shorted a tan disc Ceramic capacitor, because some sit close to the daughtercard.
If that IC is getting that hot, you should probably replace it and see what happens. Getting warm is common, hot means a short. It could be an internal IC short and you'll be good to go after replacement, or something might be shorting it. Then you will have to find a schematic and start searching.


I replaced 8E with a socket and new 74LS373. The game is running but it appears that there is something else failing because there are vertical lines through the screen and the background is scrambled. I've attached some photos of my pcb with harness and the new graphics issue.
 

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