CompuServe Thread

#A2630 crashing????!!???

7 messages in this thread
#28426From: Michael DoveJul 13, 1991 12:23 AM
Help! I am having a problem with a newly purchased A2630 board. It is GURUing at seemingly random intervals, sometimes even before it gets into the startup-sequence. Many gurus will fail or go wild and then go into another guru. I occasionally get pyrotechnics, and the only fairly consistent part is that the error usually lists an address in the $200000-$230000 range. The type of guru is pretty inconsistent. This ONLY happens when I choose Amiga with 68030 (or let it default to that)….the 68000 works fine. My hardware setup: Amiga 2000, 1 meg chip ram, GVP Impact (Series One) SCSI 8/HD with a Seagate 82meg drive and 4 megs of SIMMS in the HD controller, and the A2630 with 4meg 32 bit ram (factory direct from CBM, ordered through CATS). Now, I know there's a problem. I'd like to isolate the problem as much as possible before I start talking to CBM about it. Hopefully I'll be able to test the board on another 2000 tomorrow, but in the meantime, any hints? I think that address range is where the first autoconfig memory goes, but I can't find my hardware memory map; that would be the A2630's 4meg, right? Sigh…I wanted to have SPEED, and all it's causing is CRASHES. Any help appreciated. tmm/Richard Cunningham tmm/Richard Cunningham Die and go to BBS Hell 🙂
#28478From: Michael GerardJul 13, 1991 8:04 AM
Just a thought… someone more knowledgeable will have to confirm this, but is it possible that there is a conflict between where the 16 bit ram and the 32 bit ram are being autoconfig'd? I think you change a jumper on the GVP (or somehow disable autoconfig) to set its 4 meg of 16 bit so that it will not autoconfig and then addmem it into a known free memory location. good-luck.. – Whapping from the North Coast Michael
#28812From: Gregory B. TibbsJul 15, 1991 12:43 PM
If it is properly defined autoconfig, the OS sends the address for the board to live at to the autoconfig device. There cannot be overlap unless the board is really poorly designed. GVP had been at this too long to have that large a mistake. -Greg
#28515From: Bob RakoskyJul 13, 1991 2:35 PM
Richard, A couple of thoughts. You don't mention what rev motherboard you have in your 2000. There was a slight problem in some earlier 4.x motherboards that had a slight DMA conflict with accellerator boards. I don't remember the exact details, other than there is a tech service bulletin about the problem and the fix is relatively simple – it involves soldering a small resistor between two pins on the U601 chip. Your authorized service tech should have the details. I also seem to remember vaguely some problems with early GVP SCSI boards and the CBM accellerators, but I'm not really sure which GVP products were involved. You may want to contact GVP and ask them.
#28813From: Gregory B. TibbsJul 15, 1991 12:47 PM
I thought it was a 1K 1/4W resistor between pins 11 and 20 of U605 on rev 4.4 motherboards. It was actually for a Signetics 74ALS245 that was slow in bringing the address strobe (!AS) back to its inactive state. -Greg
#28815From: Bob RakoskyJul 15, 1991 3:51 PM
Greg, I trust your memory on this much more than mine. You even know which end of a soldering iron to use! <grin> I know I had the mod done to my Amiga, but I left the details to my service tech. Brought my machine in and told him to apply the 'tech note' concerning possible DMA/accellerator problems. He knew to what I was referring, and did the magic voodoo stuff. 🙂 Me, I stick to software! …BobR
#28811From: Gregory B. TibbsJul 15, 1991 12:40 PM
I had a similar problem a year ago and found out the problem is that the A2630 is much more noise and voltage level sensitive than just the 68000. In my case it was an overloaded power supply, or one that was very near to the limit, changing boards (and eliminating one) to drop the power draw 4 Amps turned a truly intermittant beast into a well behaving kitten. You only listed a few boards, so I don't think you would be taking your system unless you have other boards that you didn't list. My A2630 broke when I added a bridgeboard, PC hardcard, and parallel port. -Greg