Ruud, I agree it must be something with the IRQ. The machine is an 8K Chiclet keyboard 2001 PET (2.0 ROMS, 6540 ROM, 6550 RAM...so it's *real* old). When I mean it takes a long time to come up, the "*** COMMODORE BASIC ***" banner comes up quickly, but it sits there for some time (feels like 15-30 sec). No cursor is visible at this time. I suspect if I hit the keys enough it causes the machine to do something and then the blinking cursor appears (Is this blinking cusor created in Software?)...Unfortunately I have less than a minute to enter your program and execute it (which as you know with the poor layout of the chiclet keyboard is hard to do)...as I am entering the program, the PET locks up and displays "rasters" (lines appearing and diappearing accross the screen, like both the PET & Video circuit are trying to access memory at once)...the cursor disappears or turns into a white block. The only thing I can do is shut off the machine. The 8K PET uses a 6520 to read the keyboard...it's hooked into the IRQ line so I guess it generates an interrupt when this happens (I'm really not familar with the PET at hardware level). I wonder if something is causing no interrupts to be generated and then somehow causing too many interrupts to be generated. Are spare 6520's still available? I've always wanted one of these machines, as I got my start in 1979-80 by a kind gentleman who used to lend his computer to my father so I could play with it over weekends. Little did he know how much fun a 12 year old could have staying up and programming for 12 hours straight. -Chandra -----Original Message----- From: firstname.lastname@example.org [mailto:email@example.com]On Behalf Of Ruud Baltissen Sent: Wednesday, February 21, 2001 9:56 AM To: firstname.lastname@example.org Subject: Re: Help...dead 8K PET Hallo Chandra, > (1) take a "abnormally" long time for the cursor to come up and start > blinking after powering on RESET-circuit ? What happens if you reset the 2001 in the hard way eg by connecting pin 40 of the 6502 directly to GND. (won't harm if you don't do it too often) > (3) Almost within 30 sec the cursor either stops blinking or is solid and > the computer locks > up...any ideas on where to look? IRQ is responsible for the blinking of the cursor AND reading the keyboard. AT this moment I don't know what IRQ-source the 2001 uses (6532, 6520, 6522), so replace this one at least. Another check: 10 print"x"; 20 for i = 1 to 200 : next : goto 10 If it is the IRQ, then above PRG must keep on running. If it is more critical, the PRG will stop as well. Groetjes, Ruud http://home.hccnet.nl/g.baltissen/index.htm - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail email@example.com. - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail firstname.lastname@example.org.
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