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Corona Data Systems PPC-11

So much for subscribing to my own thread giving me reply notifications....

No I never looked into the keyboard further, it's packed away at the moment but good to know it may be just compressed foam pads? Though in those cases at least some of the keys ought to do something when you pound on'em
 
EkriirkE said:
So much for subscribing to my own thread giving me reply notifications....

No I never looked into the keyboard further, it's packed away at the moment but good to know it may be just compressed foam pads? Though in those cases at least some of the keys ought to do something when you pound on'em
Click to expand...

Unless of course they've all been pounded on multiple times already. :) At the very least I can type on the keyboard by touching the contacts with my fingers. A little difficult, but have been able to test some things on the machine. Unfortunately the HDD stopped working in the middle of it all (but I managed to make a backup before that happened, phew!). XT-IDE with CF installed, and all data restored.
Quick question -- I see in your pictures that you have ROM 3.20. I have 3.10. Do you have an EPROM reader that you could use to take an image of it? I'd be very interested to see the difference...
I'm still struggling to get CGA emulation to work on this system, and I wonder if it may have been something that was added to the BIOS later ...
 
rvdbijl said:
I see in your pictures that you have ROM 3.20. I have 3.10. Do you have an EPROM reader that you could use to take an image of it?
Click to expand...

I do! But you're going to have to wait a few months, I'm in the middle of a move...
 
rvdbijl said:
I'm still struggling to get CGA emulation to work on this system, and I wonder if it may have been something that was added to the BIOS later ...
Click to expand...
According to BYTE, the first Corona PPC model(s) didn't do CGA emulation. See https://archive.org/details/byte-magazine-1983-09/page/n235/mode/2up - says under 'Graphics' that you'd need to install a real CGA board.
Some of the later ones like the PPC-400 could do it, but they had a 400-line monitor so they were able to double-scan... with the 325-line models (which seem to include the PPC-21) I don't know how feasible it is.
 
VileR said:
According to BYTE, the first Corona PPC model(s) didn't do CGA emulation. See https://archive.org/details/byte-magazine-1983-09/page/n235/mode/2up - says under 'Graphics' that you'd need to install a real CGA board.
Some of the later ones like the PPC-400 could do it, but they had a 400-line monitor so they were able to double-scan... with the 325-line models (which seem to include the PPC-21) I don't know how feasible it is.
Click to expand...

Nice find in the Byte article! Didn't think of looking for that online. I'm still going to try to update the BIOS ROM at some point to a PPC-400 BIOS to see if that makes a difference. But it's kind of a hail-Mary, if it even was a software-only solution.
Last option I can think of is a VGA Wonder or similar board and see if I can make an internal cable for the built-in monitor. Would be pretty sweet to see emulated EGA on there.
 
rvdbijl said:
I'm still going to try to update the BIOS ROM at some point to a PPC-400 BIOS to see if that makes a difference. But it's kind of a hail-Mary, if it even was a software-only solution.
Last option I can think of is a VGA Wonder or similar board and see if I can make an internal cable for the built-in monitor. Would be pretty sweet to see emulated EGA on there.
Click to expand...
Personally I'd be wary of doing either of those... if the internal CRT expects a 325-line signal, the 400-line BIOS (or even a mono-emulating VGA Wonder) may not play nice with it. Those monochrome CRTs were notoriously sensitive to out-of-spec sync timings.

On the other hand, if the PPC-21 natively uses plain ol' MDA timings (and simply sets the number of visible scanlines to 325), the VGA Wonder might work... and if the PPC-400 does the same, then that BIOS might work too. Probably a good idea to check the video parameter table in both BIOSes and see what the story is.
 
VileR said:
Personally I'd be wary of doing either of those... if the internal CRT expects a 325-line signal, the 400-line BIOS (or even a mono-emulating VGA Wonder) may not play nice with it. Those monochrome CRTs were notoriously sensitive to out-of-spec sync timings.

On the other hand, if the PPC-21 natively uses plain ol' MDA timings (and simply sets the number of visible scanlines to 325), the VGA Wonder might work... and if the PPC-400 does the same, then that BIOS might work too. Probably a good idea to check the video parameter table in both BIOSes and see what the story is.
Click to expand...

Yeah, it's a bit of a gamble. What I do know is that the PC-400 output seems to work fine with a standard IBM MDA monitor. I figured if the screen doesn't look stable/normal on the PPC-21, I'll turn it right back off... :)
 
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