1994 S+ 5x Pay that sometimes works perfectly - then it breaks w/ no errors

[Daveg225]

Thanks Jim for your input.

I know it is hard to believe that the glob of solder got there during the battery replacement - just a wild theory.  I was mostly concerned that this was not a field mod of some sort and someone had intentionally shorted out pin 10 and 11.  I guess I will find out soon when I attempt to remove the short.

To be clear -  the Denom lights go out when not working - but the reels are stiff.  I have had other very weird symptoms that I am sure no one has seen since this is probably 1 in a million bug.

Crossing fingers removing solder fixes it.

Dave
 

[knagl]

Another thing to check for would be any loose coins, screws, washers, etc. that may have worked their way under the motherboard, or inside the power supply, and are causing an intermittent short. 

[Daveg225]

  That Fixed it !!

I could write a book on my adventure to the resolution, but I will try and keep it short.

Attached pix shows close up of the solder "glob" at chip U53 ; the reel chip.
How it got there - a mystery.  How the machine worked at all sometimes - a bigger mystery.

I could not remove the solder short and actually destroyed a land pattern in my attempt. So I had to remove the pROM chip 28-pin socket - yes un-soldering 28 pins and hoping not to destroy any components.

The other pix shows pin 10 and 11 securely soldered together "under" the socket.  It was very easy to fix with the socket removed.  Then fixed the cut land pattern and cross my fingers.

Powered up and it worked immediately - solid as a rock.  Left it powered up for hours and every time I went to play, it responded beautifully - but it still took all my money ( so ungrateful ).

Thanks for everyone's help keeping me focused.

Dave

[Shaggy]

Congrats for sticking with it. I looked at that picture and just shook my head. You did a great job. 

Dave