Smoking Jamma board... maybe not farkd!!! :)

[TheDriver]

Serious setback to the upcoming project, I hooked this up supergun style to see if it worked as I have not tested it yet, double checked all the wiring before I turned it on but as soon as it was switched on smoke appeared from the place in the picture below, have I buggered the board?

[cw]

looks to be a resistor pack... how about a better pic?

[TheDriver]

This is as close as I can get with the crappy cam I have:

[RayB]

Are you running +12 to the +5 ?

[TheDriver]

No, +12v, +5v, -5v & ground all in the right place. It's not smoking now but there is no signs of life 

[HaRuMaN]

No, +12v, +5v, -5v & ground all in the right place. It's not smoking now but there is no signs of life 

you let the magic smoke out.  Now you gotta find a way to put it back in...  I hope you saved it...   

[cw]

time to pull the meter out and see if the voltage lines are shorted...

the one resistor pack does look to be toasted so you will need to pull the manual and pull a part # ( if you can find one then run it through the nte crossref page http://nte01.nteinc.com/nte/NTExRefSemiProd.nsf/$$Search  )

[D_Zoot]

There's voltage somewhere it doesn't belong, edge connector plugged in backwards or something shorted or mis-wired. 

That resistor pack does look fried and it wouldn't surprise me if the 74xxx logic on that circuit is dead too.  The current that went through that resistor had to go somewhere, if you're lucky it's a pulldown resistor and it went to ground, if you're unlucky you'll have some blown out logic on the board.

What's the board?  Probably a good idea to gander at a schem to see what that circuit is before trying to fix the board.


D

[Level42]

As the picture names say Robocop, its my guess that its a Robocop.
 

[TheDriver]

Dont suppose you have any magic smoke floating around you can spare HarumaN ??

Indeed it is a Robocop board, my finger's are crossed it's just the resistor, as usual I go looking for my multimeter & cant find it!!! need to get another but im working for the next seven day's so it will probably need to wait till I get time. I did check all wiring again and all seem's to be in the right place, I never seen the board working, just took it as the guy's word I bought it from, luckily never paid much for it so if I have to cut my losses on it then so be it, il need to track down another. Is it worth fixing or would I be wasting my time???

Regards.

[HaRuMaN]

Dont suppose you have any magic smoke floating around you can spare HarumaN ??

I'm fresh out... sorry...   

It sounds like the board *was* working when it left the guy, since it smoked when it got to you.  Is it possible your power supply is putting out too much voltage?

[TheDriver]

Im not sure, it's running off a (Wei-Ya)Huai I electronics switcher with an led display which is adjustable and set at 5.0 (The manual say's it must be between 4.90 - 5.10) so thought that would have been fine. I dont know of anywhere in scotland that distribute's gameboards or anywhere that service's them, when I go up to pentranic at the end of the month month to get my monitor I may take it with me and ask harry to have a look at it, other than that I dont know.

[HaRuMaN]

Do you have a current (Amps) setting?

[TheDriver]

Yes there is a switch on the bottom for 110v or 220v, that what you mean??? I have never used a switcher before so maybe I have done something wrong with it???

[HaRuMaN]

Current... as in V = IR  (Voltage = Current * Resistance)

[TheDriver]

Sorry to sound thick but I dont know what you mean?

[grantspain]

what type super gun are you using?
a good switch mode will shut down if there is a voltage short.
if you had switched the mains selector to 110v your psu would have blown crapless so 220v is correct for u.k
current rating should not matter in this situation
my thoughts are towards either some problem with  -5v or a fault was originally on the game board

[TheDriver]

Supergun is one I did myself (although I bought the jamma harness)
That resistor that has fizzed, can I just replace it with a 10pin resistor from my local maplin or would it be a specialised resistor specific to the gameboard???

[ChadTower]

Well, here's the worst case scenario:

You euthanized a Robocop.  Nicely done.   

[grantspain]

you made the supergun yourself?
you must have a short to a switch line somewhere.
show me how you made this

[TheDriver]

Well there are too many version's of it going around on the web, never really got round to building one, so all I did was hook a jamma harness up to control's and a switching psu and video output was straight to an arcade monitor, basically what's going into my jamma cab, so it was more of a test for the jamma board. Sorry if I misled about the supergun'esque setup. I better check all my wiring before I bugger another board. I think my best bet is to speak to harry and/or one of his tech's, they have a repair room at the back of their unit for their own stuff.

Everyone learn's one way or another, unfortunately for me I am very impatient when I have parts lying around doing nothing and end up fiddling with them, sometimes things go right, other times things go wrong (in this case very wrong!)

Regards.

[grantspain]

no problem bro,you wouldn't believe the amount of stuff i have blown the crap outta over the years.
my first week at work i plugged a trojan board in upside down and my boss went mental,i had to clean the toilets for a week as punishment
is it Harry Clark at pentranic you deal with btw?

[D_Zoot]

FWIW,

Hate to be a party pooper,  but:

I just pulled a Robo Cop board off the shelf and had a very quick look at it.  Without benching the board up and tracing out some things,  it *looks* like resistor pack RA32 is the pullup for the player input controls into the buffer logic, futher it looks like that area of the pack probably runs to Jamma terminals for button inputs (via a filter section).   

This is exactly where +12 volts would have been applied if the Jamma connector was plugged in backwards.

I can tell you if +12 hit the buffers they are toast.  Also since the pullup resistor obviously passed some current, some manner of voltage exceeding +5 probably got out onto the +5 rail, so no telling what else is smoked.   The board should boot with blown out input buffers, so if it does nothing at all now she's pooched.


I'm just pointing this out so you don't spend a bunch of time and money trying to fix this board when you can probably get another one cheaper than it's going to be to repair the one you have.






D

[TheDriver]

is it Harry Clark at pentranic you deal with btw?

Yes it is, very helpfull guy, always makes time to give any information I am after, always answers his email's too. One of the few contacts I have that I use on a regular basis and their unit is 20mins from where I live!

I'm just pointing this out so you don't spend a bunch of time and money trying to fix this board when you can probably get another one cheaper than it's going to be to repair the one you have.

Already started looking, I will keep the board in the offchance there is something salvagable on it.

Thanks for the input to all who have replied, being that I am a relative Jamma virgin any tip's or knowledge I can pick up is invaluable.

Regards.

[TheDriver]

A few thing's happened this morning:

1. Decided to sell the monitor I was using as a test display, guy picked it up an hour ago.

2. Had another look at the board and wiring etc... and I got a picture

Not amazing progress but it at least confirmed the board is not completely broken.
So to make sure I don't bugger anything else up I am leaving it well alone till I build the cab and install the wiring properly. Spoke to harry clarke this morning and have a price for my monitor and will arrange to pick it up nearer the end of the month (too many work commitments to get it sooner)

The project is back on!!!

Regards.

[TheDriver]

So much for leaving it alone till I get the new pentranic!!!! I wired up a scart cable today and the picture no longer rolls, it's just black and white!!! and I wired the control's to it and they work fine, so that resistor bank that went smoky may not be gone completely after all. This is good news for me at least now I should not need to repair anything on the board.

Regards.

[D_Zoot]

I wired the control's to it and they work fine, so that resistor bank that went smoky may not be gone completely after all.

You lucky SOB !   Robocop is a 1 stick, 2 button game.    The smoked inputs must be inputs not used for this specific game (third buttons/second stick).

Man, how you get to be so lucky?  Last time I let the smoke out of a board it cost me a large handfull of silicon and hours of bench time to get it running again....   

Glad to hear yours is ok.   


D

[TheDriver]

You lucky SOB !   Robocop is a 1 stick, 2 button game.    The smoked inputs must be inputs not used for this specific game (third buttons/second stick).

Man, how you get to be so lucky?  Last time I let the smoke out of a board it cost me a large handfull of silicon and hours of bench time to get it running again....   

Glad to hear yours is ok.   


D

Tell me about it!!!! Surprised it worked myself!!! Wether it keep's on working is a different story though. As soon as I get the monitor I am going to start the build and post a project announcement, I have a feeling I will probably be asking question's at some point so it's good to know you have plenty of experience, and indeed other member's of the forum who contribute their knowledge which makes this such a great place to visit.

Regards.