Date : Tue, 15 Dec 2009 12:02:33 +0000
From : michael.firth@... (michael.firth@...)
Subject: Issue 1 versus issue 2 of Master 128?
A few differences I'm aware of, again not all Issue 1 / Issue 2 changes:
1) Some units (presumably later ones?) have the MOS ROM soldered in
2) According to the BeebMaster pages, there are two different connectors
that may be fitted where the "SCSI board" for the Domesday machine goes,
or it may be absent completely.
3) There are at least 3 different official battery options that I am aware
of - the original Lithium one that caught fire (I expect they were all swapped
out, as I think Acorn was forced into a recall), a metal boarded one with
3 AAs on that screwed into the space to the left of the PCB (where the SCSI
board would go) and a shrink wrapped collection of 3 AAs that was placed
to the left of the keyboard.
4) (a real issue 1/2 difference!) The Issue 2 PCB has a jumper re-instated
for enabling colour output on the composite video BNC, for the Issue 1 PCB
this required soldering a capacitor between components.
Andy: I for one would be interested in a pic of the early MOS ROM, as I hadn't
heard of this before.
Regards
Michael
> -----Original Message-----
> From:
> bbc-micro-bounces+michael.firth=bt.com@...
> [mailto:bbc-micro-bounces+michael.firth=bt.com@...
> .uk] On Behalf Of Andy Ford
> Sent: 15 December 2009 11:55
> To: bbc-micro@...
> Subject: Re: [BBC-Micro] Issue 1 versus issue 2 of Master 128?
>
> I would be very interested in this too as I have a list of changes
> between issues for 'B's but not for Masters. :)
>
> The only differences I have noticed really (and I'm not sure if they
> would apply to all issue 1 vs issue 2)
>
> The keyboard decoder IC is socketed on some (early issue 1 maybe ?)
>
> The (very early maybe ?) MOS rom is not just a plug in IC,
> its mounted
> on a small daughter-board with a couple of 74 logic chips. (I
> have one
> lying around, I'll get a pic if needed)
>
> I think (I'm just guessing with this one) the battery pack
> was changed
> between issues, possibly just the location of it.
>
> Andy.
>
>
> Sprow wrote:
> > Hi folks,
> > Anyone seen any documentation on what changed between issue
> 1 & 2 of a
> > Master?
> >
> > Places I looked:
> > Google, there's a mention on the BeebWiki but no actual meat.
> > BBC Micro Mailing List, a thread in 1998 asks the question
> but no answer.
> > BBC Master Service Manual, mentions issue 1 in the fault
> finding index.
> >
> > I'm trying to track down a weird problem and the only thing
> I can see on the
> > surface as different is one says "ISS1" the other says
> "ISS2". Any pointers
> > appreciated,
> > Sprow.
> >
> >
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