Quantcast
Channel: stardot.org.uk
Viewing all articles
Browse latest Browse all 3424

32-bit acorn hardware • Re: RiscPC Sound problems

$
0
0
I really would like to change those SMD Ceramic Caps but unfortunatelly don't know the values. Changed 3x47uf 16v, 2x10uf 16v to new ones and the result is the same.
Wobblestone and wiggy made some efforts with reverse engineering the Mk3 audio here:
viewtopic.php?p=401542#p401542
Checked IC34 and it has in some pin +12v and in another -12v ( i'm no expert ). All voltages are present +5, +12, -12 , -5v.
RiscPC doesn't have/use -5V AFAIK. Where are you measuring that?
Also something strange, in the C159 i measure 2.96v on the + side of the cap and -5.95 on the - side of the cap - ODD!!!
That's a series AC coupling cap - you can't measure voltages at it like that (against ground).

My bet would be the amps have blown. They blow quite readily, IME. I've fixed a good number of boards just by replacing those - IC27, IC34.

Statistics: Posted by IanJeffray — Sun Feb 02, 2025 9:19 pm



Viewing all articles
Browse latest Browse all 3424

Trending Articles