Dead IBM PC 5150 motherboard - help troubleshooting

[Tony Duell]

> 
> 
> --- Tony Duell <ard at p850ug1.demon.co.uk> wrote:
> 
> > The 5150 is a _very_ conventional 8088 design,
> > there's really nothing at 
> > all odd about it. 
> 
>  what examples could you give as a not so conventional
> 8088 board?

Depends on what I/you mean by 'unconventional'. But considerably less 
conventional than the IBM 5150 are the Sirius/Victor 9000 (It uses 6522s 
for I/O and has an 'interesting' video circuit), DEC Rainbow 
(dual-processor with a Z80 and 8088, and the video chips from a VT100), 
HP150-II (it has a CPU configured in minimum mode. But you can add an 
8087 add-on card. Since the minimum mode doesn't support coprocessors, 
the add-on card has an 8088 on it in maximum mode along with logic to 
provide the minimum-mode signals to the rest of the machine. When that 
card is fitted, the 8088 on the mainboard is disabled).

Not a computer, but somewhere I haev a 1200 baud modem that uses an 8088 
as a DSP (A very odd choice...)

-tony