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POW pcb issues


Pelly

Question

So I am a self confessed newb when it comes to working with PCB's I got into playing with cabs a number of years ago but skipped straight to playing with MAME.

 

I know, dumb right? :-P

 

Anyway, I just got a new PSU for a cab I am converting back to an original Jamma cab (minus all the Jpacs and MAME guff) I have successfully got working some PCB's, however one of them (which I was told had been tested and is working) does not seem to be the case. This is what I get when firing it up.

 

[ATTACH]75929[/ATTACH]

 

Any immediate ideas off the bat? Before I dive into obscure pcb issues are there any basics I can try? i.e. Cleaning the connectors etc?

 

Cheers

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A static screen of garbage usually means the board is not running ie. the CPU is not executing code and data is not flowing. No way to know why without getting into some non-newb testing, first thing to check would be the +5 volt, if it's extremely low it could prevent the board from booting. Could also try reseating the daughter board and any socketed ICs.
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A static screen of garbage usually means the board is not running ie. the CPU is not executing code and data is not flowing. No way to know why without getting into some non-newb testing, first thing to check would be the +5 volt, if it's extremely low it could prevent the board from booting. Could also try reseating the daughter board and any socketed ICs.

 

Thanks for responding mate. Well you would presume the power would be ok as it is a brand new PSU (and other boards are working). There is a 12v and 5v LED on the board and they both light up...? I will check it with my multimeter over the weekend though. I don't think it has a daughter board?

 

Mine looks exactly like this - http://gamesdbase.com/Media/SYSTEM/Arcade/PCB/big/P.O.W._-_Prisoners_of_War_-_1988_-_SNK_Corporation.jpg

 

However upon more Googling I found this - http://arcade.ym2149.com/pcb/snk/pow_pcb_a1.jpg

 

Is mine missing the daughter board, hence why it it not loading?

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Thanks for responding mate. Well you would presume the power would be ok as it is a brand new PSU (and other boards are working). There is a 12v and 5v LED on the board and they both light up...? I will check it with my multimeter over the weekend though. I don't think it has a daughter board?

 

Is mine missing the daughter board, hence why it it not loading?

 

Yes, you need the daughter board, it houses all the GFX2 ROMs which contain all the sprites and backgrounds, without it the game might still run as the program ROMs are on the main board, but it certainly wouldn't be playable.

 

As for the PSU, I would not assume that because it is new that the voltages have been set correctly, you most definitely need to get the multimeter on to it, the voltage could be anywhere from 4 to 6 volts.

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Yes, you need the daughter board, it houses all the GFX2 ROMs which contain all the sprites and backgrounds, without it the game might still run as the program ROMs are on the main board, but it certainly wouldn't be playable.

 

As for the PSU, I would not assume that because it is new that the voltages have been set correctly, you most definitely need to get the multimeter on to it, the voltage could be anywhere from 4 to 6 volts.

 

Thanks mate. I will contact the guy I got it off and try and sort it out. Will also test my PSU once I get a new battery for my MM.

 

Cheers

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Yes, you need the daughter board, it houses all the GFX2 ROMs which contain all the sprites and backgrounds, without it the game might still run as the program ROMs are on the main board, but it certainly wouldn't be playable.

 

As for the PSU, I would not assume that because it is new that the voltages have been set correctly, you most definitely need to get the multimeter on to it, the voltage could be anywhere from 4 to 6 volts.

 

Hey mate, just quickly.. here is the pic of my board. It doesn't even look like it has the sockets for the daughter board? A bit strange for something that was claimed to be working?

 

https://dl.dropboxusercontent.com/u/81295784/IMAG0533.jpg

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Ah, OK, looks like your board has the daughterboard replaced by those 4 large ICs at the end of the board, so they basically cram 16 small capacity ROMs into 4 large ones and place them on the main board instead. So the boards looks good to go, just check the 5 volts first.

 

Also, don't place PCBs directly on the carpet, lots of static electricity in carpet :018:

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Ah, OK, looks like your board has the daughterboard replaced by those 4 large ICs at the end of the board, so they basically cram 16 small capacity ROMs into 4 large ones and place them on the main board instead. So the boards looks good to go, just check the 5 volts first.

 

Also, don't place PCBs directly on the carpet, lots of static electricity in carpet :018:

 

Got it, thanks.

 

So I tested the PSU. It is one of those Ming Mong ones... (Cheap ones) :p Anyway the 12v reads as 10.6 and the 5v reads as 4.3. I tried adjusting the knob on the PSU to increase the voltage but that did nothing. Do you think those discrepancies are enough to cause issues? I know each boards are different but my Original Capcom CPS1 board is working.

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The 12v normally runs sound and sometimes you will get away with that voltage. The 5v on the other hand can be a bit more delicate. It will need to be as close to 5v as possible and i would say what you have is too low which would indicate a dud power supply.

Also be sure to measure the 5v at the points closest and farthest away from the edge connector as you will get a bit of voltage drop on your board. Measuring the voltage at the power supply is not enough.

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That PSU sounds like a dud. Are the games that are working more modern than this?

My last ming dung wong PSU was no good. 12 Volt was way over and 5 Volt was way under,

so no matter what adjustment I made, that was still the case.

 

- - - Updated - - -

 

This is my next PSU for boards that don?t want any negative rail.

From a Philips 286. They don?t make them like this anymore.

Still spot on and running boards fine, so I?m replacing the smoothing electrolytics for good measure and off it goes.

 

http://img.photobucket.com/albums/v186/ArtArt/Screen%20Shot%202015-03-21%20at%2012.16.08%20pm_zps5ysmewfp.png

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That PSU sounds like a dud. Are the games that are working more modern than this?

My last ming dung wong PSU was no good. 12 Volt was way over and 5 Volt was way under,

so no matter what adjustment I made, that was still the case.

 

- - - Updated - - -

 

This is my next PSU for boards that don’t want any negative rail.

From a Philips 286. They don’t make them like this anymore.

Still spot on and running boards fine, so I’m replacing the smoothing electrolytics for good measure and off it goes.

 

http://img.photobucket.com/albums/v186/ArtArt/Screen%20Shot%202015-03-21%20at%2012.16.08%20pm_zps5ysmewfp.png

 

Yeah so there is a CPS1 board (SF2 CE) which works (1992) and the one not working is POW (1988)

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Oh.. and now the SF2 CE board is rebooting randomly... must be the PSU

 

- - - Updated - - -

 

The 12v normally runs sound and sometimes you will get away with that voltage. The 5v on the other hand can be a bit more delicate. It will need to be as close to 5v as possible and i would say what you have is too low which would indicate a dud power supply.

Also be sure to measure the 5v at the points closest and farthest away from the edge connector as you will get a bit of voltage drop on your board. Measuring the voltage at the power supply is not enough.

 

Hey mate, long time no chat!

 

Yeah so the 4.3 was at the PSU, I was getting 4.1 on the harness ... Time to try another PSU...!

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OK, so I kinda feel a bit silly, the PSU was set to 220V instead of 110V which is what is getting fed into it. Switching that over and then retesting showed the correct voltage on both the 12V and 5V lines. They were one or two points over I think. Anyway, both games are working as expected now.

 

Thanks for all the suggestions guys. Wont be making that mistake again.

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