On Wed, 27 Jul 2016, Ville Laustela wrote: > > Hi. > > Ok, finally some more information on this. > I could not access your photos, probably because of my low level access. > I have only my horrendous-quality phone camera available, so I couldn’t get any good photos. Some reasonably readable ones are now here: https://www.dropbox.com/sh/oxdrc9botilxqto/AABdl6NaEsB3WHJlV8R7it6Ga?dl=0 > > On the first photo is the reversed ?, which always appears at the same spot. It would have made sense if it appeared around the BASIC banner, but it doesn’t, it’s on the lower right quadrant of the screen. The display has serious burn-in, it appears to have been used in some kind of measurement system with the same program running all the time burning into the screen. > > What I tried today: > - the RESET line of he 6502 starts low, and the jumps and stays high during reset. > - tested with another 6502 - no change > - the RAM (TI TMS4108) voltages -5, +5 and +12 are Ok > - without 6522 I get a blank screen The 6522 at C5 toggles the character set that is displayed. > - without one of the ROMs (UD6) I still got the ?-screen On BASIC 2 that is the basic ROM, so the PET did not finish it's initialization. > > During my earlier attempts I had burnt a 2716 EPROM with the petester.bin UD9 requires a 2732 EPROM unless you have one of the earlier versions that uses 7 16 K ROMs. Do you have 7 ROMs or 4? If you have a burner, you should be able to check the ROM images against zimmers.net. Pin 20 is the ROM select line. If you have a logic probe, you can check to see which ROM is being selected. image (http://www.verrua.org/pet_repair/). Inserting this in UD9 (should I use it alone without the other ROMs?) results in garbage screen. > > I also have a PETvet board (http://www.bitfixer.com/bf/petvet/petvet- operation) but it appears to have such a socket that it doesn’t make good contact with the PETs socket - all I get with it is a garbage screen (and nothing over its serial port). > > — > Ville > > > 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 2016-07-29 12:00:07
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