Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ukma!rutgers!cbmvax!fred From: fred@cbmvax.UUCP (Fred Bowen) Newsgroups: comp.sys.cbm Subject: Re: 1750 topics Message-ID: <5942@cbmvax.UUCP> Date: 9 Feb 89 21:41:07 GMT References: <5900@cbmvax.UUCP> <794@csd4.milw.wisc.edu> <5912@cbmvax.UUCP> <806@csd4.milw.wisc.edu> <5918@cbmvax.UUCP> <830@csd4.milw.wisc.edu> Reply-To: fred@cbmvax.UUCP (Fred Bowen) Organization: Commodore Technology, West Chester, PA Lines: 34 In <830@csd4.milw.wisc.edu> jgreco@csd4.milw.wisc.edu (Joe Greco) writes: >In article <5918@cbmvax.UUCP>, fred@cbmvax.UUCP (Fred Bowen) wrote: >>But capitalism has its limits, and after they have had their fair chance I >>will share the information with you. >Sounds reasonable (even if it WILL drive me to drink). :-) Sounds like fun. Gimme a call and I'll join you. >>>Does RAMDOS64 4.2 work with the 1750? >>Certainly. Maybe you have a bum copy. I assume the 1750 works on your C64 >>otherwise, power supply and plug-in gee-whiz cartridges not withstanding. >Tried it on a standard 64... no go. >Good time to mention a minor problem I've encountered once in a great >while. [...] I've had a somewhat rare problem where data in the >REU is corrupted. The 256 byte records are checksummed, and I have >gotten occasional errors where entire records would be mangled >(obviously the correct record, but certain bits returned bad for many >bytes in a row). I don't believe it's the power supply (it has a >hefty "filter" cap, and causes no other problems)... does the REU >object to many, many sequential accesses or anything unusual? What I was implying was: you are using a 1750 (C128 peripheral) on a C64. I know many folks do this without adding the resistor at R4 and say they have no problems. Have you added this resistor (390 ohm)??? The problem you are describing sounds like you haven't. This resistor shifts the dot clock timing slightly to compensate for small (TTL delays) differences between the C64 and C128 timing at the expansion port. -- -- Fred Bowen uucp: {uunet|rutgers|pyramid}!cbmvax!fred arpa: cbmvax!fred@uunet.uu.net tele: 215 431-9100 Commodore Electronics, Ltd., 1200 Wilson Drive, West Chester, PA, 19380