The reason I am interested is because I want install a High Score Save Kit for MR DO! (my kids freakin love this game).
Here are the instructions (via JROK's site)...
You will need, 1 x 24pin socket, 2 x 2764 EPROMs, 1 x DS1220AB static RAM -there's an alternative SGS Thompson part M48Z02 which should also work. This is a 2k x 8 battery backed static RAM.
Skips steps 1 & 2 for just the flip screen.
Remove RAM at location H4, if not socketed then de-solder and put in a socket.
Replace the RAM at location H4 with the non-volatile SRAM.
Burn two new EPROMs using the images below, these replace the program ROMs at board locations A4 and C4.
Power up the game and hey presto, high-scores are saved AND you can flip the screen.
Will that "cheapo" eprom burner handle this?
And, can anybody tell me what the HELL this stuff means???
I like it better when you can just buy the kit...
you need to burn (2) 2764 EPROMs and you need to install a battery backed Dallas DS1220 NVRAM. If the location the RAM goes in is soldered in, you need to desolder it, solder in a socket, and then put the DALLAS ram in the socket.
RAM:
http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR1.TRC0.A0.H0.XDALLAS+1220.TRS0&_nkw=DALLAS+1220&_sacat=0RAM SOCKET:
http://www.ebay.com/itm/10pcs-24Pin-DIP-SIP-IC-Sockets-Adaptor-Solder-Type-Wide-/140773531671?hash=item20c6c1a017:m:mzCfWMuootVY894l6PWd8DQHe can burn the 2764s for you if you don't want to buy a burner:
http://hobbyroms.com/index.html