jamma harness severe voltage drop

cleverlyj

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i'm using one of the cheaper jammaboards.com harnesses in my jamma cab, and while it works, i've got a .8v drop on the +5 line between the switcher and the edge connector, so i've got it set at 5.8 to get an even +5 on the board.

the way the harness is it uses 1 18gauge wire connected to all 4 pins for +5v. from what i've read online, this is why i'm having the problem. can anyone confirm that?

what is the best thing to do, (aside from buying another harness?) if i were to simply remove the one +5 line and replace it with 4 wires, one to each pin on the edge connector, would that work and cut down the voltage drop?

the main thing i'm concerned with - is running the board like this gonna cause any issues down the road with my jamma pcbs, as far as screwing them up, provided the board voltage stays at 5 volts?


edit - if it means anything, i'm running a very clean (edge connector wise) data east real ghostbusters pcb in it right now.
 
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You definitely should have more wires in the harness for power. Just having a single wire would be a problem.

Ideally, you should have FOUR individual red +5 volt wires connected from the edge connector to the power supply. You also should have SIX individual black ground wires going to the power supply. The wires should be 18 gauge. This will make a difference in voltage drop.
 
Those $10 JAMMA harnesses are garbage. Another 5 years or so from now, a lot of people are gonna have problems. Add more wire to "beef up" the 5VDC supply. Beef up the grounds too, if they cheaped out on those. Use heavier wire than that stupid 20-22 gage shit they used. (I sware, I've seen some with 24 gage wire....total cheap-ass bullshit). These things are just waiting to take out the power supply.....or, more than likely.....burn up the edge connector/motherboard fingers.

And for future reference....if a new harness is $10.....avoid!

Edward
 
going to rat shack shortly to pick up some spools of wire and heat shrink tubing, and will fix this. i'm gonna rerun the +12 on this too, as it also uses one damn wire (presently).
 
IF there is a Fry's on your part of town, go there instead. They have a better selection of wire and heat shrink tubing. Last time I went to RS for wire all they had was the 20 ga and smaller.

Alternatively, try an automotive parts store, they usually have heavier guage wire for rewiring trailer and lights.

ken
 
(sarcasm/whining)

Damn you people and you're Fry's!!

<end sarcasm/whining>

There were a couple of better electronics supply stores but they were down by the tech center and that is way over on the other side of town from him.

Fry's sucks, it just doesn't suck as hard as RS.

ken
 
(sarcasm/whining)

Damn you people and you're Fry's!!

<end sarcasm/whining>

+1. no fry's in colorado. but i got 20g and replaced everything, using 2 wires for the +12, 4 for +5 and 6 grounds. much better now. the voltage drop is only about .1v.
 
I can testify that the jammaboards jamma extension harnesses were trouble too.

The Bob Roberts variety may have cost 2-3x as much but it's built like a sherman tank and everything operates perfectly with it.
 

4 wires for the +5 volts reduces resistance, so more electrons can flow to destination

kinda like if you are tooling down a 4 lane highway at 75 miles an hour with medium amount of traffic and then all of a sudden theres road work ahead and everybody has to merge into one lane what happens ?

thats resistance
 
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