problems with bump n jump/ rebuilt power board, now no dice

tron guy

Super Moderator
Staff member

Donor 12 years: 2011, 2015-2025
Joined
Jun 26, 2007
Messages
23,145
Reaction score
2,593
Location
Eureka, California
problems with bump n jump/ rebuilt power board, now no dice

So I picked up this bump n jump a couple of months back. It played well for awhile, then it started acting up, and I first thought it was a monitor issue, recapped it. Then I decided since the power board was original I would rebuild it. So I did that. Now I get nothing. It's is a the blank white screen with no sign of life. Doesn't coin up, doesn't play at all.

I tested the +12 it's 12.68, the +5 is 5.09 coming out of the harness where it connects to the pcb.

To play it safe I had ordered a 100% working extra boardset from braze. Both boards react the same way. I have had dead power supplies in the past that resulted in a "white screen" the reacts much in the same way. Only I am getting the voltages I want.


Where should I look next?
 
So I picked up this bump n jump a couple of months back. It played well for awhile, then it started acting up, and I first thought it was a monitor issue, recapped it. Then I decided since the power board was original I would rebuild it. So I did that. Now I get nothing. It's is a the blank white screen with no sign of life. Doesn't coin up, doesn't play at all.

I tested the +12 it's 12.68, the +5 is 5.09 coming out of the harness where it connects to the pcb.

To play it safe I had ordered a 100% working extra boardset from braze. Both boards react the same way. I have had dead power supplies in the past that resulted in a "white screen" the reacts much in the same way. Only I am getting the voltages I want.


Where should I look next?


You should test the voltage across a chip on the board. It's possible you are getting the correct voltage at the connector but not enough voltage once the voltage makes its way through the board. Might just need a little more juice to bet the game to boot. My Satan's hollow and occasionally my solar fox will give me the white screen due to low voltage.
 
You should test the voltage across a chip on the board. It's possible you are getting the correct voltage at the connector but not enough voltage once the voltage makes its way through the board. Might just need a little more juice to bet the game to boot. My Satan's hollow and occasionally my solar fox will give me the white screen due to low voltage.

yeah that makes sense.

I guess I could just put my black lead on a ground in the harness and start testing the red lead with any and all legs on a few of the chips huh and take it from there?


The only thing I didn't change on the power supply board was the 3 adjustment pots, but I tested them with my meter and they were working as good as the new ones, so I left them alone. I probably adjusted them down is my guess at this point.
 
Ok well I went in and tested the voltages at the harness again and I was only getting +1.16 on the +5.

So I went and changed the pot that controls the +5 for the top board. After that I got +5.09 on the top harness as well as the bottom harness.

Problem now is..............

I am testing the voltages on the edge connector while the harness is connected and I am only getting +1.09 on the edge connector. Right below the connected harness. I test the +12 on the edge connector while the harness is on and I get my +12.6.

I pull the harness off and test the +5 inside the harness and I get my +5.09 again. I test both top and bottom of the inside of the harness and get +5.09 in both spots. Reconnect the harness to the boards edge connector, +1.09.

So somewhere in there is a loss of 4 volts from the harness to the edge connector of the board.

odd huh


edit: I should mention that as I was getting 1.09 at the edge connector I was getting 1.09 at the leg of several of the chips as well.
 
Last edited:
I figured I would add a couple of pics in case anyone wanted to see what I am talking about.

When I mention testing the voltage on the edge connector, I am referring to the spot right below the harness connector where the metal 'teeth' are visible. It's worth mentioning again that at the +12 I am getting my +12, the +5 is giving me +1.09


the edge connector is really clean with no decay or burnt or lifted spots (for the record)
 

Attachments

  • 009.jpg
    009.jpg
    89.4 KB · Views: 14
  • 010.jpg
    010.jpg
    89.3 KB · Views: 13
  • 011.jpg
    011.jpg
    88.6 KB · Views: 14
just guessing here but I would check your work on the PS and even then it's still possible one of the new components is bad. I've seen this scenario with switchers a number of times where the voltage drops when under load. Maybe a bad regulator? Not sure just guessing.
 
If I'm understanding correctly......When you get a good 5VDC, the motherboard is disconnected? When the motherboard is plugged in, the 5VDC line only reads 1+VDC.

Double check the rebuild on the power supply. If you installed a transistor "backwards", this could happen.

Edward
 
just guessing here but I would check your work on the PS and even then it's still possible one of the new components is bad. I've seen this scenario with switchers a number of times where the voltage drops when under load. Maybe a bad regulator? Not sure just guessing.

do you think it's the smaller (3 pronged) of the transistors that I replaced on the huge heatsink? Is that what you are referring to? As I call it a transistor I don't know what the hell it's really called. :)

Curious thing when I tested the new pot to install on the power board. I had it hooked up to my multimeter and it would rotate from 0 to 105 as you went either direction. The other 2 on the board had the same measurements (0 to 105)
Once the new pot was installed it only measured 0 to 56 (or so) on my multimeter. Is that because of the resistors, etc. in the neighborhood of this particular pot? Or is this a potential problem that I need to look at?
 
If I'm understanding correctly......When you get a good 5VDC, the motherboard is disconnected? When the motherboard is plugged in, the 5VDC line only reads 1+VDC.

Double check the rebuild on the power supply. If you installed a transistor "backwards", this could happen.

Edward

yeah I don't think I installed a transistor backwards. from my experience it is a difficult proposition to get it in there backwards, and I got them in there very smoothly in the exact way I pulled the previous ones.

And to answer your question, yes, when I have the board unhooked I get +5 inside the harness, then when I hook the board up I get +1.09 on the metal edge of the edge connector that hangs down below the connected harness.
 
ok well if I go and desolder and pull the (regulator and transistors) I suppose I should test them and make sure they are good?

how do you test the 3 pronged small one?
 
bob roberts says it sounds like I didn't tighten the nuts that hold the transistors tight enough or there may be a short/cold solder spot in that section so I will check that out and test it again before I start desoldering parts.

thanks for the feedback so far guys.
 
bob roberts says it sounds like I didn't tighten the nuts that hold the transistors tight enough or there may be a short/cold solder spot in that section so I will check that out and test it again before I start desoldering parts.

thanks for the feedback so far guys.

Bob has illustrated his dominance once again.

a quick tighten of the screws holding down the transistors and I have power everywhere now. No more drop.


lol
 
I would go ahead and change all those pots if you have them. And even more troubling, why do you and Gack Attack have the same avatar ?

ok I will change the other 2.


I thought this was the greatest picture ever and begged him to make me an avatar with my 'name' on it.
 
Back
Top Bottom