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Title: Universal Arcade Games Post by: channelmaniac on December 02, 2012, 05:44:01 PM Model: Mr. Do's Castle
Symptom: Upgrade to NVRAM Removed and reprogrammed ROMs 1 through 4 with the JROK code for adding the High Save Score feature. Removed 1 SRAM and replaced it with a socket and a customer supplied DS1220 NVRAM chip. Board would not boot with the DS1220 in the socket. Installed a 9 pin 470 ohm resistor pack to tie the first 8 address lines high and tested successfully with the DS1220 in the socket. Title: Re: Universal Arcade Games Post by: channelmaniac on January 01, 2013, 10:20:53 PM Model: Mr. Do
Symptom: No sync Board had been modified to put separate H and V sync out. Removed 2 jumper wires and resoldered two cut chip pins to remove mod. Tested. board. Title: Re: Universal Arcade Games Post by: channelmaniac on January 04, 2013, 09:17:04 PM Model: Cosmic Avenger
Symptom: Will not coin up Boardset requires +5v on the coin inputs when idle and is detailed in the owner's manual wiring diagram. Either wire +5v straight to the switches or simply use a 1K ohm resistor on each coin switch input on the PC board to tie the inputs to +5v. |