Merlin IV constant reset

[m52spy]

Hi there, been operating a few machines for over 14 years. Never had many problems. I have a normally very reliable machine a merlin IV can machine that keeps reseting at switch on. Problem started 5 days ago, happened while i was topping up coins and it went into reset. Tried switching on and off, no joy. Eventually held down selection number 3 button and this allowed normal operation. Customer has just rung up saying machine now doing the same thing. 

 

In my mind this may be due to the machine not passing some sort of internal start test and constantly trying to reset. By reset i mean 8888's and the sold out led flashing. 

 

my next step would be to check all connections on the main PCB.

 

 

Any help would be appreciated.

 

John 

[Vendo Mike]

There's a SnapHat backup battery on the board that clips directly to the top of the RAM chip it's backing up.  If it's 14 years old then it likely has some garbage in the RAM that needs cleared and that battery replaced.    I would start by turning off the machine,  pull the battery and let any residual voltage drain off.  After that, you'll replace the battery, power up and reprogram pricing, StS and any sales blocks or other odds and ends.

The batteries are available through Mouser.com (and any other electronics supplier).  

[tblake05]

Good place to start.  Plus measure voltage to the board.  Make sure its getting a solid 24v AC.

[m52spy]

Thanks chaps, I'm visiting the machine tomorrow, I'll check it out.