880139h@aucs.uucp (Rob Hutten) (11/23/89)
My 1040st buzzes. It's not the monitor, it definitly comes from the
machine itself. It's a real highpitched whiney buzz that seems to come
from somewhere on the left side. What's more, the pitch of the buzz varies
with whatever is going on on the screen, e.g. a higher pitch with a white
background and lower pitch with a black background.
Has anyone else ever heard of this, or is this completely normal and
am I making a noodle out of myself? I know someone with a 520st and it
is completely quiet.
It's getting quite irritating. Please email me any information that
any of you might have. Thanks.
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Rob Hutten 880139H@ACADIA.uucp \__/
\_,._.,-,._.,-,._.,-,._.,-,._.,-,._.,-,._.,-,._.,-,._.,-,._.,-,._.,-,._./oo\
\,._.,-,._.,-,._.,-,._.,-,._.,-,._.,-,._.,-,._.,-,._.,-,._.,-,._.,-,._..__/hcj@lzaz.ATT.COM (HC Johnson) (11/28/89)
In article <1989Nov23.031757.9434@aucs.uucp>, 880139h@aucs.uucp (Rob Hutten) writes: > > My 1040st buzzes. It's not the monitor, it definitly comes from the > machine itself. It's a real highpitched whiney buzz that seems to come The power supply is inside the 1040st. Its probably a switching unit and either the transformer laminations are loosining up or its dieing. good luck Howard C. Johnson ATT Bell Labs att!lzaz!hcj hcj@lzaz.att.com
greg@sj.ate.slb.com (Greg Wageman) (11/28/89)
Opinions expressed are the responsibility of the author. In article <1989Nov23.031757.9434@aucs.uucp> 880139h@aucs.UUCP (Rob Hutten) writes: > > My 1040st buzzes. It's not the monitor, it definitly comes from the >machine itself. It's a real highpitched whiney buzz that seems to come >from somewhere on the left side. What's more, the pitch of the buzz varies >with whatever is going on on the screen, e.g. a higher pitch with a white >background and lower pitch with a black background. The Atari ST's use a switching power supply. Such power supplies contain toroidal (donut-shaped) transformers wound on ceramic cores. Sometimes the windings are loose enough that the high-frequency switched magnetic fields causes them to vibrate on the cores, producing the sounds you hear. You or your dealer could apply a material called "corona dope" (usually used on television flyback transformers) onto the toroids to stop the vibration. This is a very common phenomenon with switching supplies. Copyright 1989 Greg Wageman DOMAIN: greg@sj.ate.slb.com Schlumberger Technologies UUCP: {uunet,decwrl,amdahl}!sjsca4!greg San Jose, CA 95110-1397 BIX: gwage CIS: 74016,352 GEnie: G.WAGEMAN Permission granted for not-for-profit reproduction only.