28 Feb
2013
28 Feb
'13
11:54 a.m.
I snagged an original IBM 5150 early model and have a couple questions abou=
t it.
The unit turns on fine and tries to boot from the first floppy drive as far=
as I can tell, I don't have a MDA monitor and that is what card it came wi=
th. When I try a VGA 8 bit card (or my Everex EGA set to CGA) I don't get a=
screen and it doesn't boot from the floppy (I change the switches 5,6 from=
OFF/OFF to ON/ON for VGA/EGA). I tried a Taxan Super Color Graphics card b=
ut my CGA monitor just shows a few lines scrolling, seems like that card is=
n't standard CGA.
IIRC, the very first BIOS versions did not support extension ROMs, and
thus will only work with MDA nad CGA cards 9not even EGA). I woiuld try
to fidn either an original MDA monitor or an original CGA card.
Not sure how much RAM this thing has either. The 16-64K motherboard has 4 f=
ull banks, there is a 64K RAM card installed, and I have a MBI Monte Carlo =
The ful lmnotherboard (4 rows of 16Kbit RAMs) gives you 64K. Then you
have another 64K on the expansion card
multi function board with 4 banks full of RAM. Anybody
have any information=
Whgat sort of RAM chips. Most likely they are 64kbit, and 9 of them give
you 64Kbytes of RAM (+ a partiy bit).. So my _guess_ without knowign the
board is hat that is another 256K. So a total of 384K RAM.
I have an idea that the early BIOS doesn;'t support 640K RAM either. I
goes up to 544K or soemthing.
-tony