tts@ttank.ttank.com (Karl Bunch) (02/10/91)
In comp.sys.ibm.pc.something I noticed they are talking a lot about upgrading CPU's to higher speeds by replacing the Crystal. Now the big question (I haven't been inside I Tandy 4000/LX for a while now) I think the LX had a removable set of crystals. Would it be worth a try to order 25Mhz crystals from National Parts and plug them in? Or is it going to be too hard on the CPU & Support chips? Maybe just that + buy a new 25Mhz 386 chip would be worth the time? While I am at it anyone know of a way to upgrade a Tandy 4000 or 4000/LX to a 486 cpu? Thanks in advance, Karl -- % ---------------------------------------------------------------------------- % Karl Bunch ||| UUCP: ..!uunet!zardoz!ttank!karl % Think Tank Software ||| INTERNET: karl@ttank.com % "...you'd be suprised how far a hug will go with Geordi, even Worf!" -- Riker
mikes@iuvax.cs.indiana.edu (Michael Squires) (02/11/91)
In article <1991Feb10.065907.311@ttank.ttank.com> karl@ttank.com writes: >big question (I haven't been inside I Tandy 4000/LX for a while now) >I think the LX had a removable set of crystals. Would it be worth a >try to order 25Mhz crystals from National Parts and plug them in? The 4000/4000LX had memory problems at 16/20MHz; there was a service mod that tied pull-down resistors onto the back of the board to keep the ringing from causing memory errors. I would suspect that even if the other chips ran at 25MHz that the board would not be reliable. 386/25 motherboards are down in the $600-800 range so I would not think that this was a good idea. In my case I purchased an AMI 386/20 motherboard with cache which runs about 20% faster than the 4000LX and moved the cards over from it. >While I am at it anyone know of a way to upgrade a Tandy 4000 or >4000/LX to a 486 cpu? Only by buying a 486 board and plugging it in; BSI was selling a new board with 0K for $1500 or so (486/25). If you run only DOS the speed differences between a 386 and a 486 may not be worth it; my 486/25 clocks at 12,000 Dhrystones under DOS, 21,000 under UNIX; 4000LX runs about 5500 and the 386/20 cache at 7500. -- Mike Squires (mikes@iuvax.cs.indiana.edu) 812 855 3974 (w) 812 333 6564 (h) mikes@iuvax.cs.indiana.edu 546 N Park Ridge Rd., Bloomington, IN 47408 Under construction: mikes@sir-alan.cica.indiana.edu