'not well' Osborne 1 mk 2

From: Don Maslin <donm_at_cts.com>
Date: Sat Jan 17 23:58:06 2004

On Sat, 17 Jan 2004, Witchy wrote:

> > -----Original Message-----
> > From: cctalk-bounces_at_classiccmp.org
> > [mailto:cctalk-bounces_at_classiccmp.org]On Behalf Of Tony Duell
> > Sent: 17 January 2004 22:54
> > To: cctalk_at_classiccmp.org
> > Subject: Re: 'not well' Osborne 1 mk 2
> >
> > Yes, that's what I'd do. Check the 5V line at a known chip (CPU, or a TTL
> > device). In a machine of this type, there'll only be one 5V line (unlike
> > in my 11/45 where there are several, from separate PSU bricks...).
> >
> > I don't know what the RAMs used are, but if they're 3-rail types, like
> > 4116s, you should check the other supplies there too.
>
> They are indeed 4116s, my comment on the glue gun was there because 3/4 of
> the RAM is obscured by (I'd guess) the floppy drive connector board that is
> sat in mountings glued to the motherboard. Still, I don't need to remove
> it....yet....

Be happy! That glued in daughter board is likely a double density
adapter for your floppies. Well worth having.

                                                - don

> > If the PSU lines look good, then check that the CPU is getting a clock
> > signal. Look also for activity (changing singals) on the address and data
> > lines from the CPU.
>
> That was next on the list :) I must advance plans to sell things to let me
> get a good bench PSU and 'scope - watching an electronics pro work on a
> machine the other day showed just how important they are!
>
> cheers
>
> --
> Adrian/Witchy
> www.binarydinosaurs.co.uk - possibly the UK's biggest online computer museum
> www.snakebiteandblack.co.uk - ex-monthly gothic shenanigans :o(
>
>
Received on Sat Jan 17 2004 - 23:58:06 GMT