U009@CCIW.BITNET (11/18/89)
Received: from CCIW.BITNET by McMaster.CA; Fri, 17 Nov 89 11:45 EST Date: Fri 17 11 89 11:10:00 EST From: U009@CCIW.BITNET Subject: Floppy Problems After 4 MB Memory Upgrade on OLD 1040ST To: Info-Atari16@Score.Stanford.edu ( I posted a request for info to the net a while ago and I thought it might be time to update y'all: > Back in early May, I purchased and installed a Datafree Industries 4 > MB upgrade card into my (old) 1040 ST. > ..... > Since I use the system about 95% in the Mac emulation mode with a > Spectre cartridge, I didn't notice anything wrong at all. I could read > and write floppies (Spectre and Mac format with a Translator-1) > without problems. It appears, however, that there is a problem on the > Atari side under GEM. If I try to copy files to the floppy, the system > will most often re-boot (like I hit the RESET switch) at some point > during the first file. > > .... info about power supply deleted .... and from some email I sent to glk3593@iuvax.cs.indiana.edu > ..... It might be that my > TOS (quite early) doesn't support >1MB properly. I am expecting the > V1.4 TOS ROMs soon and if it makes a difference, I will post to the net > and probably directly to you. Well, the 1.4 ROMs arrived and after installation, the system acted exactly the same. Spectre operations worked flawlessly while desktop copies under GEM bombed quite reliably. I recently opened the 1040 again and removed the high 2 MB bank and re-enabled the old .5 MB bank on the motherboard. The problems have apparently completely disappeared!!!! I copied >80 small files to a floppy (till it errored out because it was full!) several times under the desktop on GEM and the Spectre operation hasn't given any problems either (except for the reduced memory size). Might I ask if Mr. Pratt and/or Mr Townsend might enquire of the 'hardy boys' (thanks Tracy) in the back room if there was an early problem with the MMU which might have shown up at exactly 4 MB of memory (an off-by-one error in the decoding or something)? I'm thinking of re-cycling the 1040 (sans extra memory) thru the classifieds and looking for a current model if there isn't a simple chip swap fix. Regards, Stu Beal, VE3MWM, (U009@CCIW.BITNET), National Water Research Institute, Burlington, Ontario, Canada.
dclemans@mentor.com (Dave Clemans @ APD x1292) (11/23/89)
I would rather doubt a MMU chip problem. It is MUCH more likely that you are seeing ringing and other noise problems. A good way to check for this is to run a decent memory tester program when the board is set up for 4MB, and see where it gets errors, and what the patterns of error bits are. If you get randomness, it is almost definitely ringing or other noise problems on the dram control lines. One example to show this... Recently I upgraded a Rev. E 520 ST board to 4 megabytes using the "New World" board. Initially it showed exactly the same symptoms you got; it worked fine at 2.5megabytes, but got memory errors at 4megabytes. I eventually got it to work at 4 megabytes by shortening 3 of the interconnecting cables to about the minimum workable length (about 9 inches -> 6 inches), added inline 68 ohm resistors to the RAS/CAS lines for the upper bank, and an inline 33 ohm resistor to the MAD9 line from the MMU. dgc