Dead IBM PC 5150 motherboard - help troubleshooting
ard at p850ug1.demon.co.uk
Fri Jan 25 17:18:37 CST 2008
> > > Not a computer, but somewhere I haev a 1200 baud
> > modem that uses an 8088
> > > as a DSP (A very odd choice...)
> Tony, if you can dig out the make and model, I'd be
> interested to hear.
Better than that, I've found the modem (although not the PSU brick for it
The front panel had a label stuck on it saying CASE 460/22. Under that
was the real maker's name, Concord Data Systems. I can't, alas, find any
Concord Data Systems model numebr on it.
Inside are 2 PCBs. The top one has the RS232 connector (DB25-S, of
course) and 4 8-way DIP switches on it. It contains an 8031, an OTP 2732
alongside it, lots of TTL, RS232 buffers, etc. I assume that processor
handles the command decoding, etc. The lower PCB contains the line
interface trasnformer and relay, lots of Op-amps and analogue bits,, an
8088, 8155, 8259, 8253, a 24 pin EPROM (I don't want to pull the label
off it), an ADC0804, etc. I am pretty sure that 8088 is doing some
> Never miss a thing. Make Yahoo your home page.
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