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I've never plugged in a JAMMA harness backwards...

XtraSmiley

XtraSmiley

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Until today!

I got a Heavy Barrel in very nice condition, almost looks like it was never used. I had just tested the Vapor Trail I also got and was distracted...

These Data East PCBs of this era are a two stack and both sides are component sides, solder side on the inside.

Anyway, without thinking, I plug the HAS into it and flip the power. The OSSC shows no sync. I'm like, hmm, that's weird, the PCB is so nice... maybe it's a resolution thing?

Then I notice the power is high, about 5.02v (I start PCBs at around 4.8v if it's the first time I'm plugging them in) and then, there it is. The dreaded smell. Of burning electronics.

I quickly turn it off and am puzzled. Did I blow a cap or old part? Is something shorting? Static problems...?

Nope, I quickly realize, I've done it, now I'm part of the club!

With dread I review the board. It looks OK. I flip the JAMMA harness over and cross my fingers...

IT BOOTS! Sound and controls (at least for player 1, not checking rotation function) seem to work! Thanks goodness! I'm lucky today!

Time to fish out that JAMMA notch plug...

Anyway, happy ending this time, but do any of you guys have any idea what caused the burning smell and if I did actually damage something?
 
I think because you didn't press any buttons, and closed circuits, you might have saved yourself. If you flip the pinout, the only things that would have caused issues is the power rails being put onto the inputs. The first 2 rows on either side are Ground, so that's fine. Then the next few would have caused problems with the power being put onto the input lines.

*knocks on wood* Good to see you didn't blow anything!
 
That’s lucky!

Anyone know where I can find a JAMMA notch plug / key so I don’t do same?
 
LittleLarrySellers said:
XtraSmiley said:
These Data East PCBs of this era are a two stack and both sides are component sides, solder side on the inside.
Click to expand...
I hate to admit it but did the same with Bad Dudes. Magic smoke and a blown resistor array later I did this ONCE and oh boy never again but it was a DE board as well that got me <X :S .
I got these @kikaso-> https://laserbear.net/shop/ols/products/jamma-connector-keys

Very high quality.
Click to expand...
Interesting. Did you press any buttons as @opt2not said, or was it just too much juice at the wrong line?
 
XtraSmiley said:
LittleLarrySellers said:
XtraSmiley said:
These Data East PCBs of this era are a two stack and both sides are component sides, solder side on the inside.
Click to expand...
I hate to admit it but did the same with Bad Dudes. Magic smoke and a blown resistor array later I did this ONCE and oh boy never again but it was a DE board as well that got me <X :S .I got these @kikaso-> https://laserbear.net/shop/ols/products/jamma-connector-keys

Very high quality.
Click to expand...
Interesting. Did you press any buttons as @opt2not said, or was it just too much juice at the wrong line?
Click to expand...
Honestly I don't remember. I just remember the smell of that specific smoke. LOL.

Luckily, it seems to just be the input resistor array that burned out so yeah maybe I did. Like the game is fine just the controls are shot on certain inputs so could have been much worse.
 
Still remember doing this to one of my first cabs...left an SF2 cab at a card shop for the local fgc community and went down there to test out a new board...

nothing like the fresh smell of a medium-rare double dragon :rolleyes:
 
I have same accident like this , but i have a power supply that automatically turned off once it detect or put accidentally the board in backwards , then from now on i search those specific power supply to use in case some miss input the board backwards again
 
Yea man I did the same thing when I was putting my VLX back together after power washing it.
Was distracted and plugged in my CPS2 Multi backwards! Thankfully like you I didn't press buttons/anything, noticed it was backwards right away and shut it down.
No damage thankfully, but yea a 2sec mistake that is often death (or at least massive repairs) in our world.
 
ArcSys101 said:
I have same accident like this , but i have a power supply that automatically turned off once it detect or put accidentally the board in backwards , then from now on i search those specific power supply to use in case some miss input the board backwards again
Click to expand...
Wow, please link, this sounds like a must have!
 
Here's the sad part guys, I HAVE a JAMMA key... but I've had it out for 2 years because some of my bootlegs and Korean PCBs are not keyed.

Damn. That auto power off PSU sounds like extra insurance though!



Do you guys think I should have checked player 2? I'm on a trip now so it will be on my mind until I get a chance to check it. I didn't think about frying player 2. I guess I could look up the pin out and figure out where the power was going.
 
I use those 3D printed JAMMA keys on all my Jamma harnesses for this exact reason. Never flipped it, and I never want too.

https://www.retrorgb.com/3d-printable-jamma-key-by-greg-collins.html

MVIMG_20190731_173020_2.jpg
 
Problem with thos keys is I have a few JAMMA boards that aren't notched/cut.
So I'd have to drummel 'em out, and no way in hell I'm doing that.

Meh be careful, keys (just like condoms) suck so I'll never use one (no matter how many of my PCBs/or me die as a result).
 
jassin000 said:
Problem with thos keys is I have a few JAMMA boards that aren't notched/cut.
So I'd have to drummel 'em out, and no way in hell I'm doing that.

Just be careful, keys suck.
Click to expand...
Takes 2 seconds to pop it out when you want to play a game with no key. And 2 seconds to pop it back in.

No sense taking a risk every time you plug in a notched game over 4 seconds.
 
Lol. I almost joined that club.

With a double stack Gradius II nonetheless.

it has both pcbs having solder side facing in.

Luckily I noticed the feet were facing towards me and not away from me and never turned it on.

I still had a mini hard attack though and could only think of how much of dumbass I would have been had it flipped the surge protector on.

glad your PCB is alright @XtraSmiley.
 
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