12878Re: [midatlanticretro] Re: makeshift IBM monitor
- Jun 1, 2009Thanks for the info, Bill
Some more questions
Does it matter whether I take video from the CGA port or the composite?
So I could, if I wished, install an MFM hard drive/controller, or perhaps a hardcard. Correct?
Also, due to the different ROM, will it support a full 640k, or the 544k from the first gen?
JoeOn Mon, Jun 1, 2009 at 10:45 PM, B Degnan <billdeg@...> wrote:U33Tells you it's a 2nd REV16K-64K (upgraded) ROM set. The first rev did not have a routine for using hard drives, and some other things so most people upgraded the ROMS so they could use newer parts and memory.
(copyright) IBM CORP
this year I worked on the following other 16-64K boards, so yours is right in there among them, definitely an original, probably from late 1981 early 1983.:
Here's as much info as I can pull off the mainboard
0192592 (MARCH's with original ROMS)you have a full complement of RAM (64K) on the motherboard.
On the planar:
on on on on off on on off
on off on on off off off off
I assume you have SW1 reversed. Up means "on" if facing from the front looking down.
If you have a co-processor, two drives, CGA monitor then SW1 should be: [off on -- -- on off off on] (where pertains to RAM).
If SW1's 5 is up and 6 down - that means CGA display. Monochrome 5 and 6 are down. Never mix and match without first changing the switches before powering on. Otherwise you will fry the board and short the system.
Math co-processor 2 = up/on.
In a nutshell it looks like you have a standard configuration, no changes needed assuming you use a CGA monitor. Don't try to use monochrome with these settings. Someone did that to MARCH's 5150, and we had to replace the display card as a result.
Hope this helps.
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