IBM Engineers

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Fri Apr 9 12:40:09 2004

>
> In message <m1BBja8-000JAXC_at_p850ug1>
> ard_at_p850ug1.demon.co.uk (Tony Duell) wrote:
>
> > The PSU problem I mentioned was actually due (as ever) to dried-up=20
> > electrolytics on the output side of the PSU. Yes, I ended up having to=20
> > fix it...
> Ugh. I've got an Acorn A4 power supply - I swapped out all the electrolyt=
> ics,
> but it's still pretty knackered. It works fine until you try and boot the
> laptop off it - if the battery is dead, the PSU "flutters" on and off

Have yuou checked _all_ the electrolytics, even the low-value ones? On
both sides of the isolation barrier. Have you looked for a current sense
resistor that's gone high?

> rapidly. Very strange. What really annoys me is that Acorn considered the=
> PSU
> to be a "non-serviceable unit", so no schematics exist :-(

This may mean they didn't actually design it, but bought it in from
somebody like Astec who didn't supply schematics. I've seen this before
with PSUs, and with things like disk drives. Great pain if you actually
have to fix the thing!.

> > I have at least one CTS256 chip in stock. This is a programmed=20
> > microctroller (TMS7000/PIC7000 series IIRC) that connects to an SPO256=20
> > and which does text-to-speech conversions. It takes a serial or paralle=
> l=20
> > ASCII input IIRC.
> Yep, I've heard of the CTS256. What I want is the text-to-speech algorith=
> m,
> so I can program a PIC16F628 to replace a CTS256.
> I will admit one thing though - I'd love to know what the General Instrum=
> ents

I know the CTS256 was copy-protected (or at least all the ones I have
are...). There is some info in the data sheet on the algorithm (it's
pretty simple) since you can extend it with your own rules in an external
EPROM. I guess I now need to find that data sheet...


> LA05-148 is. I've got four SP0256A-AL2 "Narrator Speech Synth" ICs, four
> LA05-148s (no idea what they are) and four R09864CS-2030s ("(C) CURRAH
> 1984"). I guess the R09864CS is a ROM, I know the SP0256 is a speech synt=
> h,
> but I'll be damned if I can find any info on the LA05.

LA = 'Logic Array'??? Maybe a ULA for address decoding, etc? I assume
these are some add-on module for a common home computer (the list of the
3 chips sounds like something Greenweld were selling about 15 years ago...)

-tony
Received on Fri Apr 09 2004 - 12:40:09 BST