al671@unh.UUCP (Anthony Lapadula) (05/12/88)
I don't know how common this problem is, but my 1040 ST emits a high pitched whine whenever it's in operation. I had this checked out about 1 month after I bought the system, and was told that the sound is probably a sub-frequency of the switching power supply. Whatever it is, it's *very* annoying, and I wish to make it stop..... Any hints or suggestions? Note that I'm not a hardware hacker, so please include copious instructions (unless your suggestion is to bring the ST to a _real_ repair shop :-). Many thanks. /* ** What, you wanted something funny? ** --- Anthony Lapadula ** (That's ...!unh!al671 to you!) */
braner@batcomputer.tn.cornell.edu (braner) (05/13/88)
[] Over a year ago Atari informed its dealers on how to fix the problem with whining 1040ST's. It turns out that the culprit is the chip that generates the +-12V for the RS232 stuff from the main +5V supply. This chip oscillates, with the help of a capacitor, a resistor and a coil. All three should be replaced with new components of different values. I did it myself on my 1040 with success: complete disappearance of the whine. Ask your local Atari dealer for the info or a fix. (By now I have a hard disk so my ST system is noisy again :-( ) For all of you who suffer(ed) from that whine: Some people (like me) can hear the 15,750 Hz whine emitted by the ST _color_ monitor and all other standard (lo-res) monitors and TV's. It is a lot louder than that 1040 whine. It causes me physical pain. Please be considerate with your fellow people (and animals!) when using these archaic devices. Anxiously awaiting a full transition to higher-resolution video in both broadcasting and computing... - Moshe Braner (Still looking for a used 520ST system)
rich@lakesys.UUCP (Rich Dankert) (05/13/88)
In article <468@unh.UUCP> al671@unh.UUCP (Anthony Lapadula) writes: >I don't know how common this problem is, but my 1040 ST emits a high >pitched whine whenever it's in operation. > >I had this checked out about 1 month after I bought the system, and was >told that the sound is probably a sub-frequency of the switching >power supply. First off, I can say that the problem is NOT from the whine of a switching power supply in the 1040. The 1040 ST does not use a switching power supply. Second, I would check into the RS-232c port as the real culpret, although I have never seen (or heard) this personally myself, I have talked with other techs, and such and have also read , that the RS-232c was the problem. This being especially, with a Club members machine (1040 ST also) which he took the machine, and was repaired with in two days. If you havn't taken you machine into a authorized service station, Then I suggest that you should. If you're handy, or know of someone that is, change the two rs-232 chips in the machine. They can be had at any local Radio Shack store, both for less than $5.00, including chips sockets. I will suggest that *if you do decide upon this route, place in the chip sockets, and be carefull of the foils, as there is one in particular, that will lift which will make you have to use some extra hard wiring to repair. rich..... UUCP: {Ihnp4,uwvax}!uwmcsd1!lakesys!rich -- Disclaimer: The words, expressions posted here are my own..... Nothing is ever so bad that it can't be made worse by trying to fix it -- Law of the Hacker
wes@obie.UUCP (Barnacle Wes) (05/15/88)
In article <468@unh.UUCP>, al671@unh.UUCP (Anthony Lapadula) writes: > I don't know how common this problem is, but my 1040 ST emits a high > pitched whine whenever it's in operation. See if you can isolate the problem to the computer or the monitor. If it is the monitor, it is very likely to be the flyback transformer, get it replaced. If the computer is the culprit, either a transformer or a coil is the most likely culprit but I couldn't begin to tell you how to isolate which one :-).
ron@argus.UUCP (Ron DeBlock) (05/16/88)
In article <468@unh.UUCP<, al671@unh.UUCP (Anthony Lapadula) writes:
< I don't know how common this problem is, but my 1040 ST emits a high
< pitched whine whenever it's in operation.
<
< I had this checked out about 1 month after I bought the system, and was
< told that the sound is probably a sub-frequency of the switching
< power supply.
<
< Whatever it is, it's *very* annoying, and I wish to make it stop.....
<
< Any hints or suggestions? Note that I'm not a hardware hacker, so
< please include copious instructions (unless your suggestion is
< to bring the ST to a _real_ repair shop :-).
<
< Many thanks.
<
< /*
< ** What, you wanted something funny?
< ** --- Anthony Lapadula
< ** (That's ...!unh!al671 to you!)
< */
My 1040 ST has started doing the same thing recently. Not all the time -
sometimes it will start whining after an hour or so of operation, sometimes
it doesn't start at all.
I at first though it was the monitor, since the the whine often coincides
with black background on the screen (as when running PC-Ditto). But
sometimes it starts up when the modem hangs up. Weird.
I am now sure that it is not the monitor, even though it sounds like a
typical monitor whine. The proof of this is that it stops when the monitor
is off.
Anthony is right, it is very annoying. Blaming the power supply makes some
sense - a resistor and capacitor are probably forming some type of R/C
resonant circuit. Replacing the filter capacitor would probably help.
I know enough electronic theory to come up with the above explanation,
but not enough to know what to change. Is there an EE out there who can
help?
--
Ron DeBlock KA2IKT 213 River Dr.
...!rutgers!galaxy!argus Lk Hiawatha, NJ 07034
ron@wilbur.njit.edu (201) 316-6807
"Oooo...that's mean!" "No, just average."