I'm scared...720 voltage issue, but a generic question.

Jedidentist

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I'm scared...720 voltage issue, but a generic question.

So, a few months ago when I got a few new games up and running, I noticed that my 720 started displaying garbage. It would randomly credit up and then sometimes freeze. Well, since I was adding games, I figured it was a slight drop in voltage. I checked my +5V and it was reading about 4.83V so I turned up my switcher a bit and got my boards reading about 5.04V and everything's been fine.

Recently, I was having a voltage issue with my Star Wars and 720 was getting flaky again as well. I thought it was a circuit issue and dropped a new 20amp line. However, it got me to thinking about my 720, and the fact that I never really tested my switcher when I cranked that voltage up...stupid me, I know. Well, I got back there tonight and my boards were reading a little under 5V again, but the switcher was putting out about 5.4V...eek! I remember when got this game that there were a few burnt connectors with a bad crystal that got repaired and everything's been fine since. I tested the wiring harnesses and the voltage drop isn't there as they were putting out 5.38 and 5.39V. So...any thoughts? Thanks.

Derek
 
The connectors on the PCB get burnt up as well, did you test on the caps right after the connector?
After getting the power supply, harness and connectors straight there are a few other things that you can do as well.
 
I'll check those out. I've got to pull out the whole game and boards to do that, but that won't happen this weekend. I'll let you know what comes of it when I check it out next week.
 
Well, I got behind my machine and tested everything again. All my voltages coming out of my wires were spot on with my switcher's output...around 5.50v. Test points on the video and game PCBs were around 5.05-5.07. However, I took off the video PCB and just tested the solder behind the connector...and I got 5.07v. So, it seems like my voltage drop off occurs at my connector, which is probably why it gives off so much heat. However, that means my boards are only getting the 5.05v and not the 5.50v my switcher is putting out, so they shouldn't burn up. I'm not sure what else to do except replace the connectors as they burn up.
 
I'll give it a try. The headers were already replaced on J20 at least once. I know you've done a butt load of harnesses for this already...do you know the number and size of the pins and headers off hand so I can place the order today vs. waiting to get home and figuring it out? Thanks.

Derek
 
They are .156 connectors. J13 is 11 pin and J20 is 9 pin. I'd replace both the cable connector and the header on the board at the same time. Use trifurcon pins on the cable.
 
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