25V 5 Amp Bottom Board Fuse Blowing

[Slash]

I posted this question in my Buck Rogers restoration thread but thought I should probably post it under Technical Matters.  For background I have a Pascal all in one board and all connectors have been repinned.

I fired the machine up for the first time and nothing blew up or burned so that was a start. All the GI works although no insert lights (except for one) come on?

It keeps blowing the 25v 5amp slo-blo fuse on the bottom board when I try and start a game. It kicks a ball out and I plunge it but shortly after that the fuse goes, so all the coils obviously go dead.  Perhaps it's being triggered when I hit the flippers?  My understanding is that particular 5 amp fuse is for the coils.

Could this be the result of a dodgy bridge rectifier? I was testing them as per Clays guide but I don't know if my diode setting on my DMM is in a different scale? It says the value should read between .4 and .6.  Well I am getting readings between 400 and 600? Either my DMM has a different scale or they are screwed.

The only other dodgy thing is each of the displays have a number missing. On two of them they were there at one point but after messing around they dropped out again. So each display has a number out. Not sure why?  But as a result it makes it hard to read properly what messages come up on the displays when trying to go through switch tests etc.  So I thought I would try and work through methodically perhaps starting with the bridge rectifiers.

The other annoying thing is molex don't do 21 pin connectors anymore. I stupidly thought I will buy a 22 pin and cut the end off. Well I didn't consider the spaces in them are wrong  so I had to cut them out with a Stanley knife, so I'm not sure if that's causing a dodgy connection on A1-J3 and A3-J3 which might be causing some gremlins too.

[Slash]

Ok I fixed my display issues be reusing my old 21 pin connectors.  I thought I would never get the old connectors out since I had cut them all off so there was nothing to grab onto once you stick the extraction tool in.  I ended up cutting them off since I had already broken 2 extraction tools and only managed to get one or two out.

Problem was now I needed to reuse the connector since they don't make 21 pin ones anymore.  But I found a much easier way to get then out.  I used a small flat head screw driver and instead of taking the pin back out the way it was first inserted, I leveraged it forward and right thru.  Worked a treat I had 21 connectors out in less than 5 mins. 

After repinning the 21 connectors my display problems were gone.

The other stuff is still an issue.  On boot up I get the following messages:

"stuck switch" - although I cannot see any switches touching except for the coin door slam switch which is closed and the bob tilt switch which is closed (as they should be).

I also get the following rolling message: "Chute 1, Chute 2, Credit, Tilt, Slam"

I also get "Check Coils Danger Locked On" (but can't find which coil, not sure how to test for this)?

Any suggestions, are all the problems inter-related?

[Boots]

Have you checked the pop bumper switches?

[Slash]

Yep, none of those touching either.

[Slash]

Reading the manual for the Pascal board it says "If all of the first 5 messages above are displayed, the sole culprit is most probably the RETURN0 signal at pin 3 of A1J6 (which goes to those 5 switches)".

So it sounds like that could be my problem.  Obviously the connector at pin3 on A1J6 has been repinned but I jiggled it a bit for good measure.  I then followed that wire (white with black and blue) everywhere I could.  It goes to the fuse that was blowing on the bottom board then also off to the tilt bob switch, slam switch, dip switch, coin chute switches etc.  All of those connections looked ok, short of trying to reflow all the solder joints on it everywhere possible I'm at a bit of a loss?

[Boots]

What coils are cpu controlled?

[Brettski]

It really does sound like load on a solenoid, I would probably try the process of elimination and disconnect them one by one til you find the culprit.
Probably not what others would suggest, might be a better way but if all else fails it might be worth a go.

Hope you get it sorted.

Cheers: Brettski... :)

[Boots]

It really does sound like load on a solenoid, I would probably try the process of elimination and disconnect them one by one til you find the culprit.
Probably not what others would suggest, might be a better way but if all else fails it might be worth a go.

Hope you get it sorted.

Cheers: Brettski... :)

Might be the only way to find it.
Could be just a bad diode??

[Slash]

Except for 3 coils all the others were new. The knocker, and the little tilt and game over coils are the only ones I didn't replace. I have kept the old ones as backups and plan to put new wrappers on etc.

To test a diode I have to desolder one end first right?

As for the coils, if I desolder one of the sides is that enough  to eliminate it from causing problems when I turn it back on? For example if I desolder one side of the knocker coil will that be enough to see if that is the offending coil or not, ie will the game then boot if that was the problem?

[Brettski]

That's right just desolder one wire of the connector and run the test, you can test the diode with the machine turned off using your DMM.

Brettski... :)

[Slash]

Thought I would follow up with where I got to with this.  I was basically getting nowhere with solving it so I ended up getting a mate around who used to service pinnys and arcades for a living years ago.  All I had to do was supply the Karaken spiced rum for him.

After a few hours working on it without luck we basically decided to cut a wire that had been added to the coin door.  It appeared the wire was there so that it would register a credit irrespective of which coin chute the coin was put in.  As soon as we cut it, the game booted up and the "credit, tilt, slam" garbage disappeared.

However, we still had the locked on coil message.  Some coils would work but we eventually worked out that everytime one of the pop bumpers was activated it blew the 5 amp fuse.  We eventually discovered that the wires onto the coil lugs had been put on backwards (incorrect side) on each pop bumper.  

Well in my defence I went back and looked at the photos I took before disassembly and I simply reattached them as they were originally attached when I got the game.  So it was a previous owner at some point that put them on incorrectly.  As the game was in pieces when I got it, I incorrectly assumed they were correct and copied it.

I have now spent most of today just tweaking little things to make sure everything plays nicely.  Pretty much everything works now except for the 2 star rollovers that refuse to register plus a few inserts that seems to be intermittent, particularly with the vari-target.  But getting very close now to being finished  

[Brettski]

Thought I would follow up with where I got to with this.  I was basically getting nowhere with solving it so I ended up getting a mate around who used to service pinnys and arcades for a living years ago.  All I had to do was supply the Karaken spiced rum for him.

After a few hours working on it without luck we basically decided to cut a wire that had been added to the coin door.  It appeared the wire was there so that it would register a credit irrespective of which coin chute the coin was put in.  As soon as we cut it, the game booted up and the "credit, tilt, slam" garbage disappeared.

However, we still had the locked on coil message.  Some coils would work but we eventually worked out that everytime one of the pop bumpers was activated it blew the 5 amp fuse.  We eventually discovered that the wires onto the coil lugs had been put on backwards (incorrect side) on each pop bumper.  

Well in my defence I went back and looked at the photos I took before disassembly and I simply reattached them as they were originally attached when I got the game.  So it was a previous owner at some point that put them on incorrectly.  As the game was in pieces when I got it, I incorrectly assumed they were correct and copied it.

I have now spent most of today just tweaking little things to make sure everything plays nicely.  Pretty much everything works now except for the 2 star rollovers that refuse to register plus a few inserts that seems to be intermittent, particularly with the vari-target.  But getting very close now to being finished  

Well done mate!
It actually shows why it is a good idea to make sure everything is working right before a strip down and restore..
I find if I get everything working beforehand I then know it is something I have done during reassembly when things don't work.

Glad to see you moving forward..

intermittent light bulbs can take a bit to settle in, usually the sockets have dried and loosened over time, sometimes I use a drop of sewing machine oil on the dried insulator on the socket. This soaks into the insulator and expands it slightly and can often sort out dodgy sockets, also dremel them out to clear any corrosion.

Cheers: Brettski... :)

[Crashramp]

Excellent news, well done.