Date   : Thu, 11 Dec 2003 22:07:06 +0000
From   : "Nick B." <nick@...>
Subject: Re: Master 128 power supply

On Thu, 11 Dec 2003 20:13:47 +0000 (GMT), "Sprow" <info@...>
said:
[are model B and Master 128 powere supplies the same?]
> Not really.
> Mechanically they're quite different,and the Master motherboard takes
> less
> current than the BBC B and the PSU is adjusted acordingly.

Thanks, saved me a trip up into the loft to find one from a B then.
 
[noises from speaker]
> Quite normal (well,as long as it's not a loud noise!) this is due to bus
> activity - you can fix it,or at least make it better,with a 10k resistor
> on
> the 1MHz bus connector.Details on my website.
> 11.3V is within 10% of 12V,so nothing to worry about there either,

Found that, thanks again. I did seach around and look through the Master
service manuals but couldn't find any definitive figures for PSU voltage
tolerances. I'll fit a 10k resistor at the weekend when I have access to
an oscilloscope. That way I can look at the levels going into the sound
amplifier.
-- 
Nick B.