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Sega whitestar cpu 5v ground short?

The new board Jim has made lists all the compatible games on the pcb surely each game does not need a specific gal chip?
 
I can supply pals if you need them.. The blue dot one at U213 is the main one for cpu. It works on all whitestar 1 games except sharkeys shootout or some other stern around that time

If this doesn't work, then you get nowhere
 
Can't see how wrong PALs would destroy the board. So this board was working in another machine, you put different EPROMs on and stuck it into the machine it failed in? Have you measured voltages in the latter? Maybe there is a short from solenoids to 5V in that one?
 
drhex said:
Can't see how wrong PALs would destroy the board. So this board was working in another machine, you put different EPROMs on and stuck it into the machine it failed in? Have you measured voltages in the latter? Maybe there is a short from solenoids to 5V in that one?
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This board was working in x files but had reset issues, so it was sent back to me as I sold the pin, I fitted JP roms to it and put it in the jp machine, it blew the logic fuse! So I them removed this board and put jp's own board back in the JP and it's working fine again, so there were no issues with the test pinball, the problem seems to be soley around this board or the x files pin it came from, after I received the board I asked the owner to check the logic fuse in x files but it was reported as being intact so to me that would rule out x files being the issue. The only other suspect is the ramtron chip. Hope all that makes sense lol

Thanks Ronnie
 
myPinballs said:
I can supply pals if you need them.. The blue dot one at U213 is the main one for cpu. It works on all whitestar 1 games except sharkeys shootout or some other stern around that time

If this doesn't work, then you get nowhere
Click to expand...

Thanks for that Jim, I take it the other 2 pals are standard to all games? The JP mpu has all 3 soldered in.

Thanks Ronnie
 
OK, are you sure the buyer didn't do anything wrong (even inadvertently when pulling it)? Mayhem like this usually doesn't just happen... The Ramtron only has 5V available so can't see how that would blow the whole thing up.
 
drhex said:
OK, are you sure the buyer didn't do anything wrong (even inadvertently when pulling it)? Mayhem like this usually doesn't just happen... The Ramtron only has 5V available so can't see how that would blow the whole thing up.
Click to expand...

I'm the buyer :) ... As Ronnie said it was resetting but started to go in a total loop of resets. Checked all connections while machine powered down. Ronnie had a feeling it could be coming from the ramtron so checked this out and 1 leg wasn't in the socket so we thought we had found the problem.. removed and reseated with machine off and when powered back it was still resetting.
Only other thing we could see was few bad solder connections on a chip of the rottendog driver board but no fuses are blown

IMG-20240810-WA0003.webp20240809_162753.webp
 
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drhex said:
@FinalFight Good thing, can you maybe check what voltage you have on the five volt line? Seems like most of the board is fried there must be a reason for this.
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Iirc my dad checked this.. I've just called him up anyway hes going to check again (my pins are at the parents) soon as I find out I'll report back 👍
 
He just called me then said can't really get a good reading because the driver board does a reset without the cpu board being plugged in?
 
drhex said:
@FinalFight Good thing, can you maybe check what voltage you have on the five volt line? Seems like most of the board is fried there must be a reason for this.
Click to expand...

Yeah it would be good to find out what happened, 18 chips are toast! inc the 3 pals and looks like 2 of the sound roms on top of that, I'm busy now cleanig all the solder and pins out ready for new sockets.
 
Maybe this is the reset loop you were seeing? Afaik the 5V is done from the 8V winding of the transformer via a LM338K voltage regulator - there is no means of a reset there, this voltage should be there and stable. Does he have a scope to see what the voltage is looking like? Maybe there are spikes on there even which fried the chips?
 
Andy ideas on where to check this side ?
video didnt upload before so heres the link of what it was doing in the end (before this it was like every minute and it got faster and faster)
 
drhex said:
Maybe this is the reset loop you were seeing? Afaik the 5V is done from the 8V winding of the transformer via a LM338K voltage regulator - there is no means of a reset there, this voltage should be there and stable. Does he have a scope to see what the voltage is looking like? Maybe there are spikes on there even which fried the chips?
Click to expand...
sorry your message came through same time as mine... i mentioned before to ronnie about the reset while trying to check the driver board he said thats true it does reset.
i will give my dad another call and ask if he has a scope to test
 
I know the led pulses on the driver board when not connected to the mpu board but it's not the 5v led so not sure if the 5v would maybe the 5v would be on
 
How’s this for a theory ?

The high volts from the dmd somehow got sent up the ribbon cable from the dmd to the mpu?

I know sounds daft but it must have a reason
 
Not impossible but that would have had to happen your end. You’re saying that the original board works in your machine. It was continuously resetting in the other one though.
 
drhex said:
Not impossible but that would have had to happen your end. You’re saying that the original board works in your machine. It was continuously resetting in the other one though.
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Yes the Jurassic park is working normally with its own board so no issues here, the board I’m trying to repair is from the x files that final fight bought from me, so all going well and I get it working again would hate for it to get fried again
 
So looks likely the 50v has got to the mpu board somehow! But if so how has the 5v fuse survived
Or I could be wrong ?

Thanks Ronnie
 
F21 is fusing the 50V together with F20. However it happened this is probably the culprit and got shorted to 5V somehow.
 
drhex said:
F21 is fusing the 50V together with F20. However it happened this is probably the culprit and got shorted to 5V somehow.
Click to expand...
Ok thanks yes it seems that way, just not sure how this could have happened! And how the f23 5v fuse survived on x files if the board had fried

Thanks Ronnie
 
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