From: B. Degnan (billdeg_at_degnanco.com)
Date: 2006-11-16 05:10:31
Hi - I cannot remember if I have communicated any news about the Malvern CBM 8296 I reported to this group a while back. Overall status - It still does not work, but I am working to resolve. I have removed the add-on card to get at the motherboard to take some pictures http://www.vintagecomputer.net/commodore/malvern_CBM_8296/ See especially http://www.vintagecomputer.net/commodore/malvern_CBM_8296/p1010008.jpg The 6545 chip (Cathode Ray Tube Controller) in this picture is hot to the touch, probably is bad. I am currently searching for a replacement. I do not have a spare. Note also that the processor is a 6502 A, not a "B" like other 8296's. Would be slower? Questions: 1) does this chip normally run hot? 2) could the display be causing the problem? 3) Any diagnostic ideas? The Motherboard part number http://www.vintagecomputer.net/commodore/malvern_CBM_8296/P1010011.JPG 80/40 Column CPU 64-128K Assy Number 324645 Rev B Made in West Germany I have not spent time with a voltmeter, yet but that's next. Here is a good link with more info about the chips: http://www.sothius.com/hypertxt/additional/cbm8296addition.html --------------------------------------------- Here is my original post again OEM Commodore? "Malvern Particle Sizer" http://www.vintagecomputer.net/commodore/Malvern_8296/ Initial inspection of unit - does not work. 1. Monitor electronics loose 2. Made in England but US electric compat. 3. Took off monitor, unplugged from base unit. 4. The power was disconnected, board detached from monitor. I re-attached, no screen output. 5. Disk drive gave familiar long blink/2 short blinks of a IEEE drive with a good controller. Internal cable IEEE. 6. The P/N of the drive controller is 251203 REV B 1983. (This is the sfd-1001 I have been told...) 7. Motherboard: "80/40 column CPU 64/128 Ass number 324645" 8. Add on card above motherboard using two connectors to attach to mother board, with power: "Malvern Instruments Ltd." "MSM82C55A-5RS" "42041" "2,5 PC" 9. No keyboard response to Shift+RUN/STOP 10. Can hear transformer and fan moves. no part number 11. For kicks, plugged keyboard into B700 (B-128 high profile B Series) The keyboard for the Malvern CBM 8296 is mapped differently, here is an example: k=? j=7 @=9 ]=Return cursor to top left (HOME) shift = w REPEAT = e CLR/HOME = TAB 4 on keypad = a etc. Message was sent through the cbm-hackers mailing list
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