Re: Space Invaders Deluxe pcb issue

From: John Robertson
Sent: Monday, September 10, 2012 8:40 PM
To: rasterlist@vectorlist.org
Subject: Re: RASTER: Space Invaders Deluxe pcb issue

 Just for reference, I followed Mark Spaeth's method for doing the rom hack.http://cambridgearcade.dyndns.org/?q=node/72The instructions are a bit foggy in some areas....like the "S6" strapping section. I assume that you need to remove the little jumpers in the chip select section for the address lines, but why screw with that since we're no longer using any select lines? So the behavior I'm getting is with the CE line tied low (OE tied low as well).Ah, I dunno - without the memory map of SID handy I can't say for sure if that is correct. It should be - Mark knows his stuff, but you need to be sure you aren't interfering with RAM or I/O mapped memory with this single EPROM hack.

Did the board ever work correctly as a SID?

John :-#)#

I've had the board for 20 years and never really screwed with it much. After replacing all the ram, verifying everything OK with the test rom I could get it to read regular SI roms but not the SID roms that were in it. Since verifying the maskroms is a PITA, I opted for the single rom approach. But I believe they are all OK since they behaved the same in a known good SI board when using a SID sound board. There's a lotta hoopla online about the mask roms going bad, but really I can'trecall having any trouble with them. The inverted CS they use just causes major problems try'n to read them in programmers.All of my boards that used them still work fine.

---------------------------------------------------------------------------
** Unsubscribe, subscribe, or view the archives at http://www.vectorlist.org
** Please direct other questions, comments, or problems to chris@westnet.com
Received on Mon Sep 10 21:16:57 2012