Commodore used 4116's that were defective either in the upper or lower half. There are jumpers on the system board to select between them. See schematic 320351 sheet 6, for the dynamic PET. This was done as a way to save money, at a time when memory chips were expensive. We used to change the jumpers to select for 16K memory chips, and then run an exhastive memory test, and replace the chips that failed. This was cheaper than paying Commodore's price for 16K RAM. On Sat, 10 Feb 2018, vossi wrote: > Hi Mia, I have a very early cbm 3008 and it already has the upgraded > roms 901465-01/02/03. It has very rare TMS4108-25JDL-1 ceramic DRAM's > !!! I read that this are partly-defective 16k x 1 DRAMs and "-1" means > what half is not ok! > > PS: I will try to find out what's the reason for "no file not found > errror" ;) > > Christian > > > > -- Sent from: http://cbm-hackers.2304266.n4.nabble.com/ > > Message was sent through the cbm-hackers mailing list > wlevak@sdf.lonestar.org SDF Public Access UNIX System - http://sdf.lonestar.org Message was sent through the cbm-hackers mailing listReceived on 2018-02-11 07:00:03
Archive generated by hypermail 2.2.0.