From: river <>
Date: Wed Dec 15 07:42:01 2004


I'm a newbie to this forum, though I don't regard my self as a newbie
in regards to old computers.

I collect the 70's vintage processors and systems and have been playing with
them for many years.

However, I have hit a bit of a hurdle with a pair of old Intel MDS Systems. Last
week I bought a SeriesIV and a Series225 for a few dollars. The Series4 has
failed its CPIO PhaseII test with the RAM March error _at_ location 0000:8001.

I have another Series4 that I've had for a while and it works. I swapped over
the processor boards and the error followed the board. I don't have a cct diagram
so I traced the pins of the RAM chips (32 x 2118chips) and have traced it down to
possibly one of 8 chips. However, before I start replacing chips etc, I am hoping that
someone here may be able to tell me which chip it is that has failed - assuming you
have access to more info on the Series4 than I do.

The Series225 was left out under a verandah for 12years with just a plastic tarp covering
it and it was covered in mud and dirt. I spent most of the weekend cleaning it up and
checking it out. It powers up okay, but I need more info on this box 'cos I have no
doco for it whatsoever. I need to know the Monitor commands. I got a few of them out
'cos some are the same as the old Intel SBC monitors, but there are a few extra
commands that I'm not sure about. Also, does anyone have a ROM listing for the Series
225 Monitor? I'd like to know its IO addresses for keyboard, CRT, serial port. I can try
and hand dissasemble it, but I thought I'd try you guys before I embark on this task.

Oh, one other thing... at what stage does the Series225 boot from the floppy? So far
I can't get this thing to recognise it's got a floppy. I was assuming it would boot upon
power-up/reset, but it doesn't. So, maybe there's a command I need to use or it's just
stuffed and I'll have to fix it.

Received on Wed Dec 15 2004 - 07:42:01 GMT

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