On Thu, Sep 28, 2017 at 1:14 PM, Francesco Messineo <firstname.lastname@example.org> wrote: >> it's every 8 chars. Now I first have to replace the UD9 socket... Those sockets are not high quality, so that's also a good call. I replaced all of them in the 3032 I got as a teenager. > turns out the "every 8 chars" flickering was a bad UF8 (MOS 2114 variant). > UF7 (the twin MOS 2114) had also a few bad cells (3 that I could > observe using pettester.bin image). Not surprising. Most vintage stuff with 2114s, that's the first thing I look at when they fail oddly. > Now for the real "funny" part: pettester.bin shows no error both on > VRAM and on the system RAM, but using the original kernel EPROM on UD9 > gives a garbage screen. That is odd. > I've tried to swap the 16K banks but no change. Then it seems likely your 4116s are good. > Looks like there're still problems. Does the petester do checksums on the ROM sockets? The code is kinda small, so I'm guessing not. > Does anyone feel like coding a much more useful test image for 2001N? :D > Debugging a PET without a logic analyzer can require a "funny" amount of time. > I think a good test program that can be put in the kernel socket would > speed up the process. Does anyone know where the petester images came from? I saw that they were posted about 2 years ago and I glanced at a hexdump, but I haven't gone as far as disassembling the code to see what it does. If there's source out there, that would save a bit of time. -ethan Message was sent through the cbm-hackers mailing listReceived on 2017-09-28 22:00:04
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