39-in-1 - Boots to Test Menu...

modessitt

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Got a call from a customer who's internet-bought 39-in-1 cocktail suddenly stopped playing and displayed the color grid at the start of the Test Menu. He said it's been working fine for 5 years, then suddenly started doing this about a month ago.

After having him try a few things, I went out. At first I figured the Test switch was on, but it's a push button inside the coin door. On the off chance the switch went bad, I unplugged the wires to it, but that didn't help. I went to the board and verified Dip Sw 4 was off, and that it hadn't shorted internally (it tests fine - open when off and shorted when on). I also verified that pad 15 (component side) - which is the pad for the Test input - wasn't shorted to ground.

Interestingly, even though it boots straight to Test and says on the screen "Test: Next", pushing the Test button will NOT allow you to advance through the screens. It just stays on the Grid screen. Also - turning on Dip Sw 4 does NOT make it boot to Test that way, with "S2: Next" being shown instead.

I brought the board home and tested in on my bench and it does the same thing, so we know it's not a wiring issue.

It seems like somewhere a pin on a chip that detects the Test signal is stuck low, either due to a failure of that chip or some other failure. I have no way to boot to Service (not that I'm sure if it would) so I can see if it's registering Test continuously, but that would explain why I can't advance using the Test button (if it's always registered). I have another working 39-in-1, and I tried swapping the big socketed chip (Ver 309 on both) to see if that helped, and it didn't make any change.

I'm already talking to the customer about replacing it with either the working 39-in-1 I have, or upgrading it to a 60-in-1, but I was wondering if this one might be repairable? If not, I'll save it as a test board since the color grid is fine for testing monitors...
 
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