Sinistar has the flu

skramarck

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A year ago, I bought a Sinistar that had intermittent ROM errors which caused the ship to become unresponsive. A new ribbon cable (or positioning the old ribbon cable JUST RIGHT) fixed the game and it was fine for almost a year....until I had an arcade party the other night.

The random ROM errors (usually 2-0-5 or 2-0-2 with an 0-3-1 mixed in) are back and the ship is off and on responsive again. Even on the rare occasions that the game boots up with no errors, it eventually (usually within a game or two) reverts to being screwed up.

I have removed the three boards with the ribbon cables to investigate connections, reseat chips, etc.

I have not replaced the small ribbon cable, but manipulating the large cable seems to be what changes the symptoms

Anyone else ever have this particular problem? Any shortcuts to solution?
 
I've owned a few sini cabs in the past.. 95% of all my issues were power supply related.. Is your ps original, and has it been rebuilt? Have you tested voltages?

Rebuild or replace your ps.. ATX or generic switcher, adapters available.
 
You can recrimp the ribbon cables. It is very common for the wires to pull away from the IDC connectors because most people pull on the ribbon cable to remove it from the MPU board connector.

Arcade Solution has a good tutorial on how to use a vise to recrimp the cables. Just skip over the part on how to replace the cable and pick it up where the vise is used to crimp the cable. http://www.arcadesolution.com/ribbon.html


ken
 
The ribbon cable is brand new, but I can crimp it down to be sure. As for the power supply, it is probably the original. What is the best way to check for accurate voltages on this game?

My gut feeling is that perhaps the connector that the ribbon cable goes into might be bad (or have a bad solder point somewhere), but I'm not nearly expert enough to feel confident in this.

I reseated the rom chips and all seemed like they were seated well to begin with. The ram chips also look and feel ok.

I know of another Sinistar UR in the area, so it might be possible to swap some parts around to track down which board is the culprit I suppose.
 
I'm pretty sure there are test points on the power supply pcb (its been awhile).
Or open up your manual and look at the schematic for the ps. It will tell you which pins and how much voltage.. -5, +5, 12, etc

Always start with voltage, then once your good there.. Replace or fix parts.. Can't tell you how many wasted parts I've swapped out or bought cause I didn't take a minute and learn how to test voltage (under load) with the pcbs connected. Almost every error you'll get with a Williams can be caused from low voltage.

Worry about the ribbon connector later
 
I blame this problem on beer. It turns out (I think) that when I moved my kegerator to swap out kegs, I must have jostled Sinistar a bit and the power connector came loose. In giving the game a once over after reseating chips, I noticed the loose connector. The problem is that I got so excited, I forgot to power the game off and sizzled my finger. The good news is that the power connector is now in and the game is working. It's harder to play with 9 fingers, but I do have a fresh keg of beer now too, so that helps. The other bit of good news is that I noticed some loose wires on the power connector that probably could have been adding to the woes. I unplugged the game and fixed those.

Gonna leave Sinistar on for awhile to be sure, but I think he is better.

It's always the stupid stuff (and I count me in that equation too)

Steve
 
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