CPS2 and Jamma Extenders

West

Mr. Big's Thug
Joined
Mar 3, 2014
Posts
205
Hey guys,

So I got one of those el cheepo fully loaded jamma extenders from Ebay so I could connect boards outside my cab.

http://www.ebay.com/itm/Full-Jamma-...903108?hash=item58ca76c404:g:gfoAAOSwyQtVwqky

I had a look at the past posts on jamma extenders and taking a note from Lemony and James, I replaced all the spaghetti-thin +5v, -5v, +12v wires with some 14g wire hoping that would be better for power to the pcb.

All the individual pcbs I try work with the extender just fine: cps1, Cave (68000 and CV1000), etc. However cps2 doesn't want to work. I connect the jamma extender, flip on the cab (Egret2), and I hear the fan on the A board come on but I get a black screen.

Voltage coming across is 4.75v which seemed a bit low to me, but when I connect the A board directly to the cab without the extender, I get around 4.75v but the game starts up just fine.

I'm considering getting a better made extender from Bob Roberts, but before I go down that road, I figured I'd ask the experienced brains here if they had any ideas as to what the issue could be. Should I replace the grounds with 14g wire as well?

Thanks in advance to anyone with thoughts or suggestions.

West
 

JoeAwesome

I survived Secret Santa, It wasn't Easy.,
Joined
Feb 19, 2016
Posts
3,116
I'd say you're 4.75v is the problem, or at least an issue. I've heard CPS2s are power hogs, and I've seen my CPS2 orange A+B show two different voltages at the JAMMA connector and on a IC, so bringing it up to 5v-5.1v might be the answer.

Edit: here's what I'm referring to.
 
Last edited:

GohanX

Horrible Goose
20 Year Member
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Sep 28, 2001
Posts
12,490
Extenders aside, I can't get my CPS2 setup to work unless I get a solid 5.0 V measured at the jamma edge.
 

Atro

Who?,
20 Year Member
Joined
Jan 30, 2002
Posts
9,209
Use wiring from dead/used ATX PSU's. They're good enough at keeping voltages.
Your wiring may just be too long and thus you get some loss.
 

West

Mr. Big's Thug
Joined
Mar 3, 2014
Posts
205
Thx for the thoughts gents.

I'll try turning up the voltage on the psu and checking it as the AO wiki shows. Hopefully that will solve the issue.
 

Xian Xi

JammaNationX,
15 Year Member
Joined
Dec 1, 2005
Posts
27,748
Thx for the thoughts gents.

I'll try turning up the voltage on the psu and checking it as the AO wiki shows. Hopefully that will solve the issue.

Either way, change the grounds as well. Power and ground should be the same gauge wiring or ground bigger than power but never smaller.
 

West

Mr. Big's Thug
Joined
Mar 3, 2014
Posts
205
Either way, change the grounds as well. Power and ground should be the same gauge wiring or ground bigger than power but never smaller.

Thanks James, I'll change up the grounds with 14g.
 
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