Recent content by channelmaniac

Some of these use an 8 pin chip that does a buck/boost convert of the voltage to what is needed by the EPROM. A friend had a TOP2049 that had that chip fail and would do intermittent programming. Check that converter circuit. Also, look in the window of the chips that do vs. do not work. Any...

Take it from the headphone outputs...

Sounds like every other 4 slot with the volume cranked way up... They aren't hi-fi.

Post a short video

Which cartridge boards do y'all recommend to put these ROMs on? I'd like to find a bootleg cart that I can redo into Shinobi.

Nice fix! Glad to help where I can.

This Mouser part should work: 913-C62256NLL55SNXIT Unless yours uses SOJ chips... Also, for that error you got, check pins 20, 22, and 27 for proper operation on both chips. One may be missing a signal. That could cause t he error message you're seeing.

U33 almost never fails. It will most likely need to be reflowed. I can do that for you. U13 is on the sound board and is a sound ROM. U33 is the Custom DMA chip on the main board.

Download the MAME ROM file for it off the internet, unzip the file, and program the chip file into a replacement EPROM chip.

Damn... the 322 are hard to come by... I probably have 25 to 30 of the 160. 080/801 are even harder to come by. I have just enough here to build another Power Up Baseball! prototype.

What EPROMs? I know a guy...

Welcome and greetings from Texas! I've been to your country twice, to Warsaw for work and enjoyed it very much. The food was incredible as I was there when wild mushrooms were being harvested. I brought back a lot of hand made ornaments from Bombkarnia too I also felt incredibly safe walking...

Dude! Awesome :D

Look for missing signals to the ZMC2... There's one that tells it which 8 bits to shif out and if it's stuck/missing, you'll get that kind of striped screen. It's one of the low numbered pins.

OK, when you power it up, how many bongs do you hear? Just one? When you turn the test mode DIP on and go into the sound tests, what sounds / effects do you hear OK? Which are bad?