I finally fired up Robotron yesterday. The US wiring harness I have was modified to use an AT/ATX power supply, so I connected it to a switching arcade psu.
I still haven't gotten around to hooking up the monitor or joysticks, but the Robotron boards luckily have a little display to indicate errors.
It didn't light up immediately on the first attempt, but after a couple of seconds it blinked 1-3-1 repeatedly. After that initial boot, it showed 1-3-1 almost instantly after turning on the power.
The manual says that 1 means RAM failure, and the two next numbers indicate which bank and chip has the problem. From what I could tell, this means that the chip in the upper left corner of this picture is the faulty one:
The manual says to check for normal voltages on the chip: -5V/pin 1, +12V/pin 8, +5V pin 9. They were all correct in my case, and I'm not exactly sure what that means. The manual doesn't really explain if wrong values means a bad chip, or if it indicates a different problem altogether.
I'm hoping for the last one, meaning that I should just replace the RAM chip. I tried reseating it, but that didn't help. I guess the next step would be switching it with another chip in the same bank, and see if the error message remains the same, but I didn't think of that yesterday.
It may be pretty obvious from my postings, but I'm not very familiar with troubleshooting and modifying arcade PCBs. As far as I can tell these ram chips are 4116, and they seem to be somewhat rare nowadays, but I found them online.
I also found an article describing how to replace them with 4164 DRAM, but I'm not sure if I'll go that route. Any tips?
Posts
No comments:
Post a Comment