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AmigaTech Forum · Expansion Hardware

#Memory problems

9 messages in this thread

#65207From: Dean B. McDanielSep 10, 1989 1:00 PM

help! I recently purchased a 8-up microbotics memory board. When I installed the board into the A2000HD system I began to experience random system problems. While the memory tests that came with the board ran fine, it looks like the board is dropping data in a random way. The memory sims installed were checked in a MAC II system so I know the memory is OK. Has anyone else experienced these type of problems. Help! Dean

#65241From: Larry RosenmanSep 10, 1989 5:53 PM

what rev is your motherboard?? there is a KNOWN problem with 6.x mother boards and SOME peripherals, it is a MOTHERBOARD problem. Larry ROsenman

#65247From: Dean B. McDanielSep 10, 1989 7:19 PM

Larry: Thankyou for your respons. I've opened up my machine and looked for the rev. level of the motherboard. It appears that the board is level 6 I can't find a level marker other than the one etched on the PCB. The information on the mother board is "A/W 312723 Rev 6 PCB Assy 312720 GX-211 VO 8903 FAB DWG 312722" It is both Etched in Copper and printed on the silkscreen. The machine was just recently purchased. I could not find a "6.x" on the board anywhere even under the powersupply/Drive frame. If you have a ECO number or information on the ECO I would appreciate any information that you have in regard to the problem with my using my microbotics 8-up memory board. Thanks for the help. Dean

#65259From: Larry RosenmanSep 10, 1989 9:24 PM

I have a 4.2 motherboard. COntact YOUR dealer for any info on what is going on. There was recently a LARGE discussion in various places on the problems with any rev 6 (the .x meant ANY character). I have no further information other than SOME rev 6 and above motherboards have a noisy bus on them and C= is aware of it. Dont know the current status other than that Larry Rosenman

#65285From: Dean B. McDanielSep 10, 1989 11:32 PM

Thanks Larry, the noisy bus sounds alot like it might be my problem. I will contact the dealer on Monday. Dean

#65301From: Don Curtis/SYSOPSep 11, 1989 12:42 AM

Dean, Check the information in message 65300 about a possible fix for you. Don

#65300From: Don Curtis/SYSOPSep 11, 1989 12:41 AM

Larry, IF the motherboard has a Signetics 74ALS245 at postion U605 then the fix is to put a 3.3K resistor between pin 20 and pin 11. This ONLY applies to the Signetics chip, any other manufacturer's chip should not cause the problem. Don

#65253From: Betty Clay/SYSOPSep 10, 1989 8:44 PM

Dean, I use the MicroBotics 8-up board, with memory chips I installed myself – and have had no problems at all. Did you install the shield between the 8-up and the adjacent boards? Betty

#65284From: Dean B. McDanielSep 10, 1989 11:30 PM

I installed the shield when the board was next to the disk controller. However I also tried it in other slots as well. But thanks for the suggestion. Dean