Anyone experienced with Smart Ball Skeeball Alleys?

acebh

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Anyone experienced with Smart Ball Skeeball Alleys?

Picked up a non-working Smart Ball Alley "Skeeball-style" game by Smart Industries. I know technically it should just be called "alley" since it's not Skeeball.. far from it from what it seems. It's the one with the big Dot Matrix Display. Anyone have experience with these and/or manual, schematics?

Measured 6v+ A/C voltage on output of bridge rectifier which seemed odd. Tested via diode test on multimeter and seemed to test okay except across the A/C lugs of the bridge rectifier, which confirmed why it was leaking A/C. Replaced the bridge and now the MPU board leds light up.. green led blinks, then all (green, yellow, red) kindof take turns and eventually all lock on. The led on the power supply (looks like for 5v indication) doesn't come on until the 3 leds on the MPU board lock on. I'd have assumed the 5v indicator on the power supply would light up right away.

Needless to say game is still not working and I'm measuring low voltage on the power supply 5v lines. Looks like 3.38v. I can tweak the potentiometer and get it near 4.1v but seems to be as high as it goes. Without any load (just plugged into transformer) the 5v output measures 14v (again odd).. with load it's 3.38v. ICs on the MPU board seem to be getting low voltage so it's no wonder it's not working. I'm wondering if a voltage regulator (NTE956) or the 2n3055 transistor partially died and aren't carrying current as they should. I plan to replace the NTE956 with an LM317T that I had in my salvage pile and try that. I figured I'd check to see if anyone has some experience with these alleys and what each of the LEDs are on the MPU.. or if anyone knows where I can find schematic/manual.
 
Fixed

Just thought I'd post an update. After replacing the LM317T the 5v was stable (so the NTE956 was bad). Also realized display ribbon cable was plugged in backwards on the driver board. CPU is now booting just fine, one green blinking led is all that should be lit when the MPU board is fully working. Not getting any audio right now, but going to try hooking up another speaker to the audio cables before assuming it's a board issue.
 
When I had an issue with mine, the LM317 would overheat and throttle back voltage. In reality, it was being asked provide all of the voltage because the main power supply from the transformer had a couple of bad connections: 1 at the fuse holder and the other where the transformer wires attach to the power supply board.

I assume you have the wiring diagrams (I drew my own).
 
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