Jamma PCB sucking down the +5V?

[AE35]

Hey all!

I have a Exerizer PCB that sucks down the +5V, to about 4.2V...with the game still running fine
Except there's no sound

I can't adjust the +5V enough to reach 5V, and I've tried two different power supplies. I've tried
another game PCB, that works fine WITH sound.

Any idea what I should check? What could be cutting down the +5V ?

Thanks!

Nicholas

[BobA]

Could be a bad cap.  Check and see if any look puffy or if any other component looks like it is getting very hot. check that your pcb connector is clean and has no corrosion.

[AE35]

Hey!

The connector is fine....besides this happened out of nothing it seems:)

The caps looks very good, no visible cue.

What value cap could be the problem? I mean, if such a board uses a particular kind of cap for
this purpose.

Thanks!!
 
Nicholas

[MonMotha]

Where are you measuring the voltage?

If at the game board, check it at the power supply terminals, too.  If it's correct at the power supply but very low at the game board, check connectors and possibly upgrade to bigger power wires (minimum for power hungry boards should be 4x AWG20 or 2x AWG18 and preferred 4x AWG18 for both +5V and ground).  If at the power supply, just replace the darned thing.  They're cheap enough as to not generally be worth repair unless they're some specialized unit.

[armi0024]

If this is a new PS, also make sure it is set to 110.  Many have 220/110 and if they are set to 220 will not be able to keep up. 

There are a lot of cheaper power supplies on the market now too, just be wary of this.  The brands we trust are Happ and Wei Ya.  No power supply is perfect but when we have tried carrying some of the other brands like Min Dong or other Chinese PS manufacturers, which have much better margins for us, we end up having too many problems.  This is a problem with power supplies on Ebay, like joysticks on Ebay.  I can literally buy many of the power supplies on Ebay I see for 1/2 the cost of a Wei Ya, but it's not worth the extra headache to us.

[RayB]

Usually audio circuits use +12v for amplification. Check those readings too.

[AE35]

Hey!

Yeah, the 12V is fine

Maybe I should look for a new Exerizer board!!

[mgb]

I'm not sure if that board has socketed Rom chips on it or not. But if so, its worth it to pull them, clean the legs and reset them and see if that makes a difference. Sometimes dust and grime will give issues.
As far as ruling out a bad psu, when you put in another jamma board, were you able to get the voltage upto 5v?
I imagine at 4.2v, you'd be experience some problems like resets and garbled graphics.