[comp.sys.amiga] A500 hummmmmmmmmmmmmmm

dleigh@hplabsz.HPL.HP.COM (Darren Leigh) (06/10/88)

In article <620009@otter.hple.hp.com> ljc@otter.hple.hp.com
(Lee Carter) writes:
>Small but very annoying problem I have with my Amiga.
>One of the first things I did when I got my machine home was to plug the
>audio output into my stereo. When I did I was greeted with a loud hum from
>the speakers.

I had a similar problem when I attached my modem: the Amiga audio
outputs would squeal (not hum) in a very annoying fashion.  It turned
out that I was using a fully wired serial cable and clipping the
unneeded conductors cured the problem.

Having the Amiga hooked up to a stereo is great!  You wouldn't believe
how the sound effects in Asteriods really enhance the game.

Darren Leigh -- now hacking at Hewlett Packard
dleigh@hplabs.hp.com
hplabs!dleigh

hal@hpscdc.HP.COM (Hal Work) (06/10/88)

I also have, and am still having this problem.  I have two small Sony
powered speakers attached to my 500 and get an intermittent hum.  Sometimes
it's there, sometimes not.  I'd love to find out how to stop it.

grr@cbmvax.UUCP (George Robbins) (06/11/88)

In article <4580005@hpscdc.HP.COM> hal@hpscdc.HP.COM (Hal Work) writes:
> I also have, and am still having this problem.  I have two small Sony
> powered speakers attached to my 500 and get an intermittent hum.  Sometimes
> it's there, sometimes not.  I'd love to find out how to stop it.

As the other person suggested, check your RS232 cable for connections
to pins 11 and 18.  Snip any such wires.  Of for more the most effective
truncation, remove R339 and C502.

Any remaining noise represents either grounding problems or power
supply / ground noise within the system you can't easily defeat.

The audio connections on the RS232 connector were a gesture towards
A1000 compatibility - support for "answering machine" type applications.
Oh well...

-- 
George Robbins - now working for,	uucp: {uunet|ihnp4|rutgers}!cbmvax!grr
but no way officially representing	arpa: cbmvax!grr@uunet.uu.net
Commodore, Engineering Department	fone: 215-431-9255 (only by moonlite)