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falter
November 8th, 2013, 11:28 AM
I have a Commodore PC10-III a friend gave me years ago that has a Sota 386si ISA card in it. It allows the computer to switch between 8088 and 80386 modes. The machine sat for quite a while unused and consequently I found it would not post anymore. However on removing the Sota card and reinserting the 8088 directly, it works.

I am wondering if the Sota card is anything unique or worth saving... ie. worth expending the effort to try and troubleshoot, and if cards like that really lived up to their billing and sped things up that much. I'm not clear exactly on how you can pump 386 power down into an essentially 8 bit computer. Looking for info on how it all works and if I should try to get this thing working again.

modem7
November 8th, 2013, 11:35 AM
Try reseating any socketed components.

joekster
November 8th, 2013, 11:37 AM
The sota card is cool and uncommon, although most collectors prefer stock machines. Intel had a 8088-to-386 and some other companies too. If you're getting rid of it, i'd to pick it up and see if its fixable.

falter
November 8th, 2013, 11:40 AM
Also a separate question -- this machine came with a VGA ISA card. I would like to run it on RGB to be more period correct, and it looks like it has a built in RGB port, but removing the VGA card and connecting to the RGB with my IBM Enhanced monitor produces no video. Is there likely a jumper setting somewhere?

falter
November 8th, 2013, 11:41 AM
I've tried removing and reseating both CPUs on the card, along with the socketed chips. The only way I can get the PC to post is to take the 8088 chip from the board and plug it directly into the motherboard. There is a little switch on the back whos function I'm not certain of but I assume switches between 8088 and 386 mode. I note that when the hard drive boots, it comes to a menu and you can choose between either mode to boot it.

modem7
November 8th, 2013, 12:03 PM
There is a little switch on the back whos function I'm not certain of but I assume switches between 8088 and 386 mode.
Likely. The 286 based 'accelerator' shown in the manual [here (http://www.minuszerodegrees.net/manuals/Accelerator_286.pdf)] has a second switch to control cache operation.

falter
November 8th, 2013, 12:11 PM
I did some reseating again. I noticed the pins on the 386 socket had a bit of corrosion on them, which i'm attempting to clean. Now if I have the switch in the down position, the machine will boot.. however I think that's the 8088 mode, as when I tell it to boot in 386 mode it says 'this will only speed up in 386si mode' when the driver loads. But with the switch up.. no post. I'll make an attempt at cleaning that socket and any others I find that look bad.

modem7
November 8th, 2013, 12:18 PM
I noticed the pins on the 386 socket had a bit of corrosion on them,
Sounds like a likely cause.


Also a separate question -- this machine came with a VGA ISA card. I would like to run it on RGB to be more period correct, and it looks like it has a built in RGB port, but removing the VGA card and connecting to the RGB with my IBM Enhanced monitor produces no video. Is there likely a jumper setting somewhere?
See the 'Video' section of the Wiki page for the Commodore PC10-III
The page is [here (http://www.vintage-computer.com/vcforum/showwiki.php?title=Systems:Commodore+PC10-III)].

Maverick1978
November 8th, 2013, 09:35 PM
The Sota adapters, IIRC, have dip switches that need to be set as well, as they will work with both 8088 and 8086-based systems. You can find the manual (http://classiccomputers.info/down/misc/Sota/Sota_386si_Manual.pdf) and the software (http://classiccomputers.info/down/misc/Sota/Sota_386si.zip) on my site.