From: utzoo!decvax!harpo!npoiv!npois!houxm!houxa!houxi!houxz!ihnp4!ihnss!knudsen Newsgroups: net.micro Title: HELP with Color COmputer 64K RAM upgrade Article-I.D.: ihnss.1454 Posted: Mon Feb 21 17:26:51 1983 Received: Tue Feb 22 05:15:21 1983 Reply-To: knudsen@ihnss.UUCP (Mike J Knudsen, ihnss!knudsen) Can someone help me answer these: 1) How ffast must the RAM be in the CoCo? I put in some 400-ns cycle(?)-time chips and it mostly works. But i've seen ads for 250-ns access(?)-time chips. Are mine too slow? 2) Why does my "E"-board CoCo sometimes get the idea on power-up that I have 4K instead of 32K, when the RAMSIZE jumper is in either 32K or 16K slot? 3) Why does BASIC *not* have problem (2) above when when a cartridge (with interrupt lead cut) is inserted? Does this load the bus just right? Note--the Radio Shack Diagnostic rompack now consistently reports my RAM is OK, tho it can only check the lower 16K (it's an old pack). PS--I found that 64K rams can be very intolerant of +5 voltage variations. Mine work best on exactly 5.0 V. The Shack had set my CoCo for 4.8V, and the chips were very flaky. Also, you have to set the one jumper to HIGH, not LOW, so that the 'ls02 buffers MA7; the SAM can't drive that line well enuf by itself. thanks, mike k