Help with arcade PCB question

[robbo007]

Hi guys.
I've been using my machine as a mame machine with a Jpac up until now. I've secured a WBML PCB (Bootleg) which the owner tested before sending out. (seems legit). The PCB has a hacked jamma connector soldered onto it. I connected the board to my machine and nothing. No sound. No image. I've defintally connected it the right way. No doubt there. I've tested conductivity on the connector and the pins seems to match the online resources.

Whats going wrong? Why does my JPAC work fine and the board not? I'm assuming the board is good because the seller seems very legit.
Regards,

 

[robbo007]

Could it be that the JPAC does not need the same power requirements as WBML PCB?

 

[Derick2k]

Hello!

What board/game is that?
What machine are you hooking it up to?
What Power supply does it have?

The JPac does not use power from the jamma edge, but from the USB connection to the Mame PC.
And depending on which power supply you are using on your machine, it could become faulty if powered without a load connected.

 

[robbo007]

ok thanks. The PCB is Wonderboy II monster land. The arcade machine is a generic JAMMA one. IT looks like my PSU is not preforming correctly, take a look at this video: https://www.mediafire.com/file/vgz1uo1o7j24j2a/IMG_7226_2.MOV/file
Im getting strange voltages from the first few pins. I'll have to also open the machine and check the PSU for capacitor problems.

 

[Derick2k]

I think the range is wrong on your meter, switch it to V instead of mV and test again, please.

Looks like your psu/harness is wired to supply all voltages, so that's good.

Give the contacts a good cleaning on the pcb jamma edge connector also, cant hurt.

Im sure you know this but jamma pinout for voltages

 

[robbo007]

Ok after setting to V (AC) on multi meter I seem to get 14.x volts on pins 3-6. Is this normal?
Because I think the Konami Wonder Boy Monsterland PCB requires 5v on pins 3-4 ?

 

[evilsim]

@robbo007 you will definitely want to set "V (DC)" on your multimeter, *not* AC.

> 14.x volts on pins 3-6.
Switch to DC and see what you get. The jamma pins diagram shown just above shows what voltages to expect on those pins.
goodluck!

 

[Derick2k]

Please make sure to select DC and test again just to be sure,

Pins 3/4 - should read +5V or close to it
Pin 5 - should read -5V or close to it
Pin 6 - should read +12v or close to it

Let us know what those read.

 

[robbo007]

My PSU is a Hantarex US150. Multi meter reading now reporting 0v power on pins 3-6 JAMMA connector. (On V mode DC). I've checked by using the actual soldered pins instead of sticking the probe into the jamma sockets.

So I traced it back to the psu. I removed the molex connector stuck black on ground and tested other pins. All read 0v except -12 shows 1v. Very strange. PSU has power as the fan connected to it works. Caps don't look like they are buldging. I will dismantle it this weekend and try and clean it up and see if I see anything strange. I'm not very electronic savvy so I dont know what the next step would be on testing the PSU?

 

[robbo007]

Right so cleaned up the board a little and visually inspected it. Some of the orange caps look a tad bulging. I'm thinking to attempt a recap as the PSU is pretty dead. NO green LED either. Looks like there are about 16 caps. Are these readily available still?
Thanks,

 

[Derick2k]

You might be better served to just replace the PSU with a new one, you will have to do some wiring work to your harness.

It should be fairly easy for you to recap the psu, you don't have to get the same brand, just the same rating and type. But no guarantee it will work if other components have gone bad.

 

[robbo007]

PSU replaced all working. Was completely dead. Would have been more expensive to recap and find the problem than a new one.

 

[Derick2k]

Nice! Now you have a proper working setup.