Re: 8250LP - fault, how to fix?

From: Adrian Vickers (
Date: 2002-02-14 18:10:29

At 09:25 14/02/2002, you wrote:

>Adrian Vickers wrote:
> > Unfortunately, the boards are entirely different. Excluding the 'LPs
> > daughterboard, there are the same number of what I assume are firmware
> > chips (identified as 901887-01, 901888-01 and 091467-01), but I wouldn't
> > like to try to swap them. They have a different number of pins, for
> > starters... :)
>There are two different versions of the 8250LP mainboard: One takes the usual
>24pin ROMs from the 8250, the other one has 28pin sockets for 2564 EPROMs.

Mine is one of the latter type, then.

>tried to put ROMs into the EPROM sockets, it doesn't work.

Erm, no, it wouldn't....

>You can safely replace the 6530 on the adaptor board with the 6530 from the
>8250, or you can even replace the whole adaptor board with a 6530.


I tried that, and presto! Drive booted normally (it even returned 2.7 as 
the DOS version when queried from my 8032-SK.

Tried replacing the adaptor board + old 8250 chip, and it worked - but not 
correctly by a long shot. Still returns "drive not ready", although you can 
send it an "Initialize". It will then attempt to read one or the other 
drive (irrespective of whether there's a disk in it or not), but fail with 
a "read error", then "drive not ready" errors until reinitialized, 
whereupon it tries the other disk, repeat ad nauseum.

I thus conclude that:

The 6530 (imprinted 901885-04 0683) is blown, wheras the 6530 (imprinted 
901885-04 0383) is okay, but the wrong version to correctly drive the, erm, 
drive. So to speak.

So, anyone got a spare 6530 (with "901885-04" printed on the top line, and 
"0683" printed below it) they'd be willing to part with? Alternatively, if 
you're in London, could I borrow one for a day to try it out?

Thanks! There's hope for the old monster yet!

Cheers, Ade.
Be where it's at, B-Racing!

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