What's new

8bit

Beginner
Joined
Sep 22, 2019
Messages
18
Reaction score
2
Location
Dublin
So I am an idiot, and I connected my JAMMA connector up to my Atomiswave backwards and turned it on!

I let out the magic purple smoke, and it smelled awful.

Any ideas on what will need to be repaired on the PCB to get this board back up and running? Are there some things that will obviously be damaged before I open it up and see?
 
Well that sucks. You are probably better off just getting a replacement since AW MBs can be had cheap enough.

But yeah, just open it up and start looking for burnt components/traces and start testing.
 
This is why you ALWAYS use a key in your JAMMA connector.

But here is what happens when you hook it up backwards

+5V gets run to the buttons 4 and 5 inputs for players 1 and 2

-5V gets run to button 3 for players 1 and 2

+12V gets run to button 2 for players 1 and 2

and if your cab is equipped with coin counters another voltage input gets routed to right joystick for players 1 and 2

This will basically cook everything on the PCB starting with control inputs and the extent of the damage really has to do with how long you left it powered up like that.

In my experience though, stuff like this will completely ruin a PCB even if you replace the burnt out components and get it to boot again it can significantly weaken the other "still working" components and cause them to fail early.

I had a Tekken 3 gifted to me where someone did this, I got it booting again replacing a number of components on the input lines and one of the video sync chips, but after a few week the RAM and CPU and other parts started fail.

My recommendation:
Step 1: key your JAMMA connector so this doesn't happen again
Step 2: As Derick said... just buy a new AW and cross your fingers that your cart is ok.
 
Last edited:
post pcb photo's incase it was caught by a buffer chip.
and sort your jamma connector like twistedsymphony said.
all you need to do is flow some solder beween the contacts.
 
A quick check shows that at least P1 shot 2, P2 Shot 1, and shot 2 are stuck "ON" in the IO test menu. The machine seems to fire up OK though, it also seems to read carts just fine.
 
trace the pins for those buttons that are stuck on. something in the chain will need to be replaced.
 
Can you see it ? lol
IMG_3003.jpg
 
Last edited:
I wonder what it is about Atomiswave that makes you plug it in backwards? It's one of two boards I've ever done it to.

I remember mine surviving, but honestly, I can't remember if I ever checked the buttons.
 
Bummer. Someone already said it but that's why your JAMMA harness / extension should always include a small plastic "block" (or whatever you call them...I honestly just realized I don't have a word for it) so that it's physically impossible (without gorilla levels of strength) to install your harness / connector in incorrectly.

I always wondered why the JAMMA standard even allowed for this to be a possibility? Hindsight being 20/20 there could have been some design thought up that only allowed for a one way connection.

Leave two pins blank with a recess, but not equidistant to each other. Put plastic notches in the harness. Only goes in one way

so the edge would look like

XXXXXOXXXXXXXXXXXXXXXOXXXXXXX
XXXXXOXXXXXXXXXXXXXXXOXXXXXXX

Added a pin on each side to allow for the O, which is an OPENING in the pins. Like the break between power and signal currently on JAMMA, except there are two and they aren't in the same spots distance wise compared to each other.

So if the harness has a plastic notch in place where the O exists on both sides, and the O is offset compared to its sister O, plugging in the harness in any configuration that is NOT correct would have you bashing plastic up against pins, meaning it wouldn't fit. Only by plugging your harness into the edge in the CORRECT configuration would all the two spots to marry together correctly.

But hey, JAMMA is JAMMA. Can't change it now lol
 
ZD = zener diode.
i should work without it, put a big blob of solder on it and slide it off the pads.
:D


@awbacon1 - the jamma standard DOES include a cutout in the board and blocker in the edge connector.
it's just that some people are too damned lazy to implement it.
 
ZD = zener diode.
i should work without it, put a big blob of solder on it and slide it off the pads.
:D


@awbacon1 - the jamma standard DOES include a cutout in the board and blocker in the edge connector.
it's just that some people are too damned lazy to implement it.
Oh I know JAMMA has the cutout between power and signal, and that the blockers exist. They are installed in all my harnesses :)

I just meant they should have gone FURTHER with the design. The EDGE is a standard, but I'd have put more than one key in, and made sure they were offset distance wise. I'd then have put these two tabs in the injection mold for the harness connector, and forced the CONNECTORS to adhere to this standard. Then I'd force everyone to only buy from approved vendors so the market wasn't flooded with knock off connectors that didn't have the proper tab system in the mold in the first place.

That way its truly impossible to plug them in reversed.
 
but then i would have to smack you for creating a closed market,
jamma intentionally uses standard parts - if you want custom shit then use sega boards! :D

and you only need one keyway, you cant plug it in backwards.

a history lesson,
long before jamma everybody had their own wiring standard, but they also used different keying positions so you wouldnt plug a board into the wrong cab.
jamma is actually very close to the old sega 28pin standard but you cant mix them.
 
but then i would have to smack you for creating a closed market,
jamma intentionally uses standard parts - if you want custom shit then use sega boards! :D

and you only need one keyway, you can plug it in backwards.

a history lesson,
long before jamma everybody had their own wiring standard, but they also used different keying positions so you wouldnt plug a board into the wrong cab.
jamma is actually very close to the old sega 28pin standard but you cant mix them.
lol closed market. Yes that's true...my plan if I was the engineer back in the day on JAMMA would result in a single source for the appropriate components. But it would be a bit more foolproof and that would keep more boards alive. So I call my theoretically monopoly a "think about the pcb's!" humane solution hahaha
 
engineers all over the world for about 40years have managed just fine by writing "parts side" on the edge connector with a marker pen. :P
 
ZD = zener diode.
i should work without it, put a big blob of solder on it and slide it off the pads.
:D
blob the entire thing connecting all 5 pads? or just where two of the legs are?
 
Back
Top