Desperado
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where i can find this information please?
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Cbm pet 8296-d black screen
- Thread starter Desperado
- Start date
daver2
10k Member
Marked on the physical disk drive unit!
Dave
Dave
daver2
10k Member
It is probably on the other side of the drive...
However, the -038 (what’s in there already) is designed for Micropolis disk drives whereas the -048 is designed for MPI disk drives - so they are not interchangeable. You need to find a -047 for Micropolis disk drives.
Down the snake...
Dave
However, the -038 (what’s in there already) is designed for Micropolis disk drives whereas the -048 is designed for MPI disk drives - so they are not interchangeable. You need to find a -047 for Micropolis disk drives.
Down the snake...
Dave
daver2
10k Member
If you want to repair the unit you will have to get a PCB made for the replacement of the 6530 with the appropriate firmware downloaded from the Zimmers website burnt into a suitable EPROM.
I, personally, wouldn’t bother and would buy one of these: https://www.thefuturewas8bit.com/sd2pet-future.html. Other (similar) solutions are available - including a PCB layout for the DIYer.
Those are, I think, your options.
Dave
I, personally, wouldn’t bother and would buy one of these: https://www.thefuturewas8bit.com/sd2pet-future.html. Other (similar) solutions are available - including a PCB layout for the DIYer.
Those are, I think, your options.
Dave
daver2
10k Member
By the look of your photograph you have Micropolis disk drives. I confirmed this by looking at your photograph and comparing it to the disk drive plans in the maintenance manual.
The compatible devices for the 6530 at location UK3 is therefore:
901483-03 DOS Version 2.5 6530-038.
901885-04 DOS Version 2.7 6530-047.
Dave
The compatible devices for the 6530 at location UK3 is therefore:
901483-03 DOS Version 2.5 6530-038.
901885-04 DOS Version 2.7 6530-047.
Dave
Desperado
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Ok thanks so much Dave...the only thing that i can do is buying a replacement board
Gary C
Veteran Member
A mega 2560 can run a PET disk and they are only £13 + £8 for the SPI SD card.
Need to connect up the wires DIY though or make up a board.
github.com
software could still do with some polish
Need to connect up the wires DIY though or make up a board.
GitHub - Gary-Clark/CBM-PET-IEEE: File system for the CBM pet
File system for the CBM pet. Contribute to Gary-Clark/CBM-PET-IEEE development by creating an account on GitHub.
github.com
software could still do with some polish
Kakemoms
Experienced Member
I can confirm this. I have several CBM disk drives, and they all have the 6530 RRIOT that has a small ROM inside. The ROM differs from version to version, and with all the different chips you are really not going to find a replacement soon. Your best option is therefore the replacement board with a 6530 and an external ROM on it. If you want to make the board yourself, you can find more info here: http://retro.hansotten.nl/6502-sbc/6530-6532/Ok thanks so much Dave...the only thing that i can do is buying a replacement board
daver2
10k Member
I have never tried it with an 8296. Give it a go...
I’ll have a look and see how compatible one is.
Dave
I’ll have a look and see how compatible one is.
Dave
daver2
10k Member
I am not seeing anything in the 8296 that would cause my PETTESTER firmware to not work.
However, it will not know anything about the additional RAM - so it will not be tested in full.
No guarantees though - but it would be interesting to know whether it actually works or not for other potential repairs in the future...
The firmware checksums are likely to be incorrect (due to 'tweaked' Commodore BASIC firmware to support the additional memory etc.).
Dave
However, it will not know anything about the additional RAM - so it will not be tested in full.
No guarantees though - but it would be interesting to know whether it actually works or not for other potential repairs in the future...
The firmware checksums are likely to be incorrect (due to 'tweaked' Commodore BASIC firmware to support the additional memory etc.).
Dave
Desperado
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Ok i give to my friend...always in edit socket?? Thanks!
daver2
10k Member
Yep, always in the EDIT ROM socket.
Dave
Dave
daver2
10k Member
So my PETTESTER is working...
It looks like you have a monitor brightness issue (or some other monitor issue).
I suspect you may also have a video logic issue also.
I will look at the video in freeze-frame mode a little later to see if I can ascertain what is going on halfway down the screen.
Dave
It looks like you have a monitor brightness issue (or some other monitor issue).
I suspect you may also have a video logic issue also.
I will look at the video in freeze-frame mode a little later to see if I can ascertain what is going on halfway down the screen.
Dave
daver2
10k Member
The 8296 appears to use High = Black and Low = White. The 8032 (CPU board from the SuperPET - and hence the SuperPET monitor) appears to use High = White and Low = Black. This accounts for the inverse video we are seeing. Have you tried adjusting the screen brightness ?
The 8296 appears to have a completely different circuit for the video sub-system, even though it appears to work in an 'enhanced' mode. I don't, however, see any reason why the PETTESTER should not be driving it correctly.
A 'normal' PET has separate video RAM. The 8296 uses 'system' RAM and shares this with the CPU.
My PETTESTER has clearly worked out that the 'video RAM' = Main RAM (in the area $8000 to $87FF) is working OK (otherwise it wouldn't move on past the VDU RAM check screen. It has also checked out pages 0 and 1 of the RAM.
The next thing to do is to compare and contrast the 80 column display in my PETTESTER documentation to what you are obtaining (and observing) on the screen. In particular, look at the first 256 characters at the top of the screen. Are the text and graphic characters displayed correct to my documentation?
Next, look at the 'fixed text' that should be observable on the screen, the 4-digit checksums for each of the ROMS and the 2-digit countdown value. Are these correct or not. Is the 'rubbish' that appears half-way down the screen fixed or does it vary?
I suspect some problem from the CRTC address and data bus through the buffers to the main RAM to be at fault somewhere.
I would be looking around UC9 (6545 CRTC), UA9 (74LS257) and UB9 (74LS257) first.
Dave
The 8296 appears to have a completely different circuit for the video sub-system, even though it appears to work in an 'enhanced' mode. I don't, however, see any reason why the PETTESTER should not be driving it correctly.
A 'normal' PET has separate video RAM. The 8296 uses 'system' RAM and shares this with the CPU.
My PETTESTER has clearly worked out that the 'video RAM' = Main RAM (in the area $8000 to $87FF) is working OK (otherwise it wouldn't move on past the VDU RAM check screen. It has also checked out pages 0 and 1 of the RAM.
The next thing to do is to compare and contrast the 80 column display in my PETTESTER documentation to what you are obtaining (and observing) on the screen. In particular, look at the first 256 characters at the top of the screen. Are the text and graphic characters displayed correct to my documentation?
Next, look at the 'fixed text' that should be observable on the screen, the 4-digit checksums for each of the ROMS and the 2-digit countdown value. Are these correct or not. Is the 'rubbish' that appears half-way down the screen fixed or does it vary?
I suspect some problem from the CRTC address and data bus through the buffers to the main RAM to be at fault somewhere.
I would be looking around UC9 (6545 CRTC), UA9 (74LS257) and UB9 (74LS257) first.
Dave
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