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Did I fry my power supply?

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Macone

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Hello all, I have been working on a DIY arcade project and I am afraid I might have just killed my power supply or maybe something worse and was hoping someone with more knowledge than me might give me a place to start trouble shooting.

So in the excitement of "I'm almost able to play games!" I inadvertently hooked up the +5v jamma lead to the -5v contact on my power supply. When I first plugged in the power supply the power on led lit for a brief moment then turned off I am assuming because it was very unhappy with being hooked up wrong and possibly killed it. So after you are done laughing at me does anyone have any ideas on what I can do? Is there anything I can check or is a new power supply in my future, or might it be something further down the line? Left my millimeter at work so I cant check till tomorrow... I am just kind of panicking right now. If its helpful information I am running a Mv-1b mother board and everything was working fine hooked up on the table top a couple weeks ago.

Thanks in advances for any help!

Mac
 
Macone said:
I inadvertently hooked up the +5v jamma lead to the -5v contact on my power supply.
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what was the JAMMA edge plugged into?

I wouldn't be so worried about killing the PSU as I would be about killing whatever was plugged into your JAMMA harness.
 
Sounds like an MVS board, they don't use -5 so hopefully hasn't done it any damage.

The risk is that if -5 was grounded (as it probably would be on a board that doesn't use it) that you've sent your +5 straight to ground. If it isn't grounded (and just isn't connected) then nothing will happen

My money is +5 has been grounded and blown something. Time to check to see if the PSU has a fuse, if it does it's probably blown, if it's a fuse you can also probably replace it. If it doesn't have a fuse, something would've blown up and made itself a fuse
 
Well, thanks for the replies but it looks like my hooking up one wrong wire night have just blown up...pretty much everything. The power supply is cooked. There was a fuse but it didn't blow so I don't know what good it was doing. I also had the RGB to VGA converter hooked to the same line and it appears to have killed the TV I was using as a display as now it will only show a black screen with moving lined where the screen saver logo use to move around the screen when nothing was hooked up. Not sure if the MVS board is shot since I have nothing to test it with till a new power supply shows up....stupid -5V! guess I should learn how to read labels better.
 
well, the fuse is there for over draw protection; to keep your house from burning down, not to protect your electronics. By running -5 to the +5 on your items it was the same as hooking up ground and +5 backwards, and if all your electronics popped before drawing too much it's entirely possible that your PSU is still working despite frying everything you hooked it up to.
 
Power supply was dead as a door nail when I put my meter on it this morning. I am hoping that it blew before the mother board did, its already been an expensive mistake that I wont make again.
 
Yep you've absolutely grounded +5.... the fuse was probably there for the incoming 110/240v

If the RGB to VGA converter was installed on that same +5 line and you grounded it... Yeah that's not good since +5 is connected on the VGA connector as well.

No laughter here. We've all made mistakes in this hobby, it's the nature of the beast. I've seen power supplies turned up to far and JAMMA edges shoved onto non JAMMA boards many times before.

You didn't hurt yourself or start a fire - but next time you may not be so lucky if you're not careful. Chalk it up to experience
 
From what I understood -5V has been sent to whatever was connected to the power supply instead of +5V. This is exactly the same as if you had swapped +5V and ground.
This also means instant death of TTLs, RAMs, ROMs, etc.

And yes, don't be too hard with yourself, I've repaired hundreds of boards and I still make stupid mistakes sometimes leading in killing a board (killed a Vapor Trail few months ago by shorting ground and +5V while probing some chips).
 
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Same, we all make mistakes. I've let the black magic smoke out of lots of electronics over the years. :D

It's only failure if you don't learn from it.

I try to get in the habit of triple checking all of my wiring:
1. Plan out where everything goes before you start, write or type a list of all the connections.
2. Verify each connection is made correctly as you make it.
3. before you apply power re-check every every connection again to make sure everything is in the right place.

In the case of your PSU you also had terminals that were unused. You can't just skip over these, you should also be verifying that the pins or terminals with no connection are intended to have no connection.

I do this when I'm making harnesses, or cap kits or anything where a mistake could cause damage to the electronics. It only takes a few minutes to check over everything again, but powering it on with wires crossed could set you back days or weeks waiting for new parts plus more sunk costs to boot.
 
twistedsymphony said:
It only takes a few minutes to check over everything again, but powering it on with wires crossed could set you back days or weeks waiting for new parts plus more sunk costs to boot.
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^That...

i killed luckily only my PSU in December while trying to build adapter from my supergun which wasa wired for a pandoras box to my mvs and in that process shoted the thing... Luckily it killed only the PSU and the lights in my staircase... ;( and and i had to wait for a new psu...
 
twistedsymphony said:
Same, we all make mistakes
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I necked a Nanao 2930 (Blast City) monitor tube... It had minimal burn, and really only needed a recap.
It was a very sad day.

I also burned up a HAS by wiring the PSU like a computer PSU (aka yellow 12v and not 5v).
 
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oh i also did the reversing 5 with -5 wiring error...that's a classic.

Loud bang and white smoke, pretty spectacular if you ask me (my wife didn't find the smoke and smell very amusing thought)

PCB didn't suffer any damage, at psu side it looked like a diode fried (hard to recognise since that part was totally melted).
 
I like that this thread has turned into us admitting mistakes.

I've definitely made my share, whether burning up traces learning to solder as a teenager, or just simply using nice stuff on shoddily grounded outlets at rental properties.

We used to have a Terminator 2 pinball at work. When a co-worker released the magic smoke on the MPU PCB accidentally, I nicknamed the day Magic Smoke Monday. I still take extra caution on Mondays lol.
 
twistedsymphony said:
could be a good learning opportunity, open up the PSU and see if you can fix it
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any tips on what to replace? i wanted to try to repair the two dead psus i have here (both pretty bad quality, the second one simply died on me, i swear... now i have a suzo mwp-606 since a few people recommended them. But still it would be good to have some working psus as a backup...
 
MoppelTheWhale said:
any tips on what to replace?
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Obviously every PSU is different, with something like this where it was a fully working PSU that popped, I'd start by opening it up and checking for burn marks or blown components/blown traces, check any internal fuses.

For older PSUs that simply don't hold voltage well or otherwise "died of natural causes" start with a cap kit, if it has a fan I usually like to replace the fan too if it's noisy or really grungy.


after that check the diodes transistors and transformers. you should be able to find guides on how to check those and there aren't more than a handfull in a PSU so it's easy enough to simply check all of them.

I bought a box of 8 NAOMI PSUs for $40, they were all dead and I brought them all back to full working condition just by replacing bad caps, and some corroded resistors (and a few fans for good measure). People tend to throw out bad PSUs because they're cheap but unless it's just a generic JAMMA PSU I always recommend recap/repair, and unless you've got bad damage to the PCB itself, it's probably repairable. And if you're trying to learn to fix this stuff then it's a great low-risk way to learn. If you're a beginner would you rather try to fix and accidentally make worse a $500 game PCB or a $15 PSU?
 
skate323k137 said:
I like that this thread has turned into us admitting mistakes.
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Hehe, well no one wants to publicly admit to it because of the personal shame we feel over our past mistakes.
I think it's important to be honest here, no one was born an arcade/hardware super star.

We are all at different skill levels, different levels of past experience and we are continuing to grow in our/this hobby.
I like that this community is open/welcoming to new people, and NOT afraid to admit we are all human after all. ^^
 
If fuse has not blown , the primary circuit of the PSU (where AC current is plugged ) is doing his job.So the problem should be in secondary circuit where voltages have been already regulated.Open the PSU and look for burnt/shorted components especially diodes and transistors.I guess there should also some digital IC that controls outputs.Is it a generic PSU?
 
you guys are awesome. Thanks for the war story's and not making me feel like an idiot.
The final report is the power supply, monitor, and motherboard are blown up. I dont have high hope's but I'm going to try to save the motherboard, need to do some research. Oddly enough the RGB to VGA converter is fine. Yippee it stayed alive to kill the monitor. Haha. New power supply doesn't have -5v I made sure to take that right out of the equation! Thanks again guys I think I am going to like this forum.
 
caius said:
If fuse has not blown , the primary circuit of the PSU (where AC current is plugged ) is doing his job.So the problem should be in secondary circuit where voltages have been already regulated.Open the PSU and look for burnt/shorted components especially diodes and transistors.I guess there should also some digital IC that controls outputs.Is it a generic PSU?
Click to expand...
Thanks for the tips. Yes it's just a generic PSU from Amazon. There doesn't appear to be anything visually wrong with the PSU nothing burn or discolored. I poked around with it for a bit but could not find the issue.
 
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