On Fri, 14 Jan 2011, hwarin@neuf.fr wrote: > Hi, > > Thanks a lot for all those answers - My MB is a revision 8032090 with 8032090 is the universal dynamic PET. It can be either a 40 or 80 column machine, depending how the jumpers are set. Also the screen editor ROM is different for 40 and 80 column configurations. Schematics on zimmers.net > UA17/UA19 socketed. I've tryed "just to see" to swap and to simply UA4 thru UA19 are the main RAM. Odd numbered locations are the lower memory, and even numbered locations are upper memory. It looks as though someone tried to fix lower memory. > remove 4116 at those position. With no RAM on UA17 or UA19, it won't > even emit any beep ... I'll try to find out some 4116 in my stock ! Would a > 4164 make the thing ? Another question I'm asking me is where is "low" > memory ? Is it UA4 to UA11 or above UA11 ? > I've tryed the floppy drive test - without success - it was a good try ! > My plan would be > 1) RAM - Swap 16Kb low/hi (don't know if a quick hack is possible) to try > to isolate or change the problem It should be possible to jumper the bank select lines. I don't see where right now. I will have to look at this when I have more time. > 2) Bad solder .... as something had changed once (and I had something > readable on display) when I pulled out UD12 from it's skcket. UD11 and UD12 are not necessary. They are application ROMs. > 3) Try to be more intelligent. > Bad news, my "ancestral" Schlumberger CRC 5212 osciloscope died after half > an hour of usage following 15 years of storage ==> Must find something > to replace it. It's usually the filter capacitors in the power supply. They need to be run ever so often or they go bad (moisture infiltration). wlevak@sdf.lonestar.org SDF Public Access UNIX System - http://sdf.lonestar.org Message was sent through the cbm-hackers mailing listReceived on 2011-01-14 07:00:02
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