Magical Power Supply? \ VOGONS

Magical Power Supply?

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First post, by WazMeister

Posted on 2021-03-15, 23:22

WazMeister Offline

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I think I may have fairies of some sort living in my 486 PSU...

Recently bought this 486 and have done it up, with SOund card and CF + gotek driver.

Loving it, apart from... when I first received it there was sound coming from somewhere. like a HDD loading or I dunno... like the LED flicker that sort of noise. I put it down to the HDD....
There was also a spectrum loading sort of sound when booting... it comes to the testing HIMEM and there is load a spectrum loading sound effect as if I was loading jet set willy!!!

THen in games, I hear faint little beeps and bops trying to do sound effects of current game but really poor...
I finally put sound card in other day, nice and fine yet this loading sound at HIMEM still happend and all the weird flicking / beeps as if something was loading.... realising I have a CF adaptor I'm little lost to where the sounds are coming from. I ran my ear all over... and it's not coming from the speaker... seems to be hovering around the PSU!
DOes this 486 have a magic speaker inside the PSU?!?!?!
Everything seems to be running fine, games (apart from the odd crash which i guess is expected), I see no issue with power or anything............

I then finally put case on tonight, thinking it must be PC Speaker.... realising as I closed case it was unplugged!!!!!!!!!!!!!!!!!!!!!!!! Now plugged in I get a clear BEEP from it at start up which I never got.. but I still get this specturm loading sound effect at the HIMEM test and still in games in the background, over the speakers using sound card... it's annoying now.

WHere is it coming from?!?!?!

Reply 1 of 14, by WazMeister

Posted on 2021-03-16, 08:39

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Bit scary no one knows, I try upload the sound if I can !

Reply 2 of 14, by weedeewee

Posted on 2021-03-16, 09:01

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google coil whine ...

Right to repair is fundamental. You own it, you're allowed to fix it.
How To Ask Questions The Smart Way
Do not ask Why !
https://www.vogonswiki.com/index.php/Serial_port

Reply 3 of 14, by WazMeister

Posted on 2021-03-16, 09:50

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Thanks, yea could be that.

It sort of changes pitch and the when while games are loading, playing or benchmarking through..
Sometimes I think it's a PC speaker making sound effects but its not!

hmmm wonder where I can get a slimline PSU to fit this deskmaster 486

Reply 4 of 14, by dionb

Posted on 2021-03-16, 09:55

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More specs needed... what sound card? What PSU? What motherboard?

Some sound cards are unshielded with unfiltered 12V/5V lines. Any crap in EMI (over the air) or via the power lines will be picked up and amplified.

As for the PSU, it could be anythng from coil whine to spluttering leaking caps or worse. Open it up and see/listen what is going on (and be careful about the mains voltages inside).

Reply 5 of 14, by WazMeister

Posted on 2021-03-16, 11:24

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Year I've opened and listened.

Was getting these noises before sound card was installed, but its a ESS 1869 ESDRV GOLD16k
PSU is Samsung 103C
photos below

if I was going to replace the PSU, where would I find such a thing to fit? It has a 10 pin grey connector too which seems odd.
https://photos.app.goo.gl/VMHYe446GubKyXpF9

Reply 6 of 14, by WazMeister

Posted on 2021-03-16, 13:48

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I wonder if I could use this?
How do I get it to work with the AT
https://docs.rs-online.com/8d14/0900766b815da4f1.pdf

Reply 7 of 14, by weedeewee

Posted on 2021-03-16, 14:14

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PSU seems to have different pinout from normal AT P8P9 connector.

Maybe you can use that, if it fits in your case and if you re-use the cables from the old PSU and the cables are long enough (easily remedied, extra cable) and the -5V line is not required (easily remedied, few extra components)

Right to repair is fundamental. You own it, you're allowed to fix it.
How To Ask Questions The Smart Way
Do not ask Why !
https://www.vogonswiki.com/index.php/Serial_port

Reply 8 of 14, by WazMeister

Posted on 2021-03-16, 21:01

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Here is the sounds.

One is when the computer loads, specturm loading sound for a HIMEM test
One is on a menu of a game, flicking over buttons I made a tune!!!
One is a game installing

https://drive.google.com/file/d/10hjONjvHOPee … iew?usp=sharing

https://drive.google.com/file/d/10kogxZXnaFK8 … iew?usp=sharing

https://drive.google.com/file/d/10cKnUKmg4tC7 … iew?usp=sharing

Cant be COIL whining!?!?

Reply 9 of 14, by WazMeister

Posted on 2021-03-16, 21:01

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P.S Turn volume up to hear the weird noise.

Reply 10 of 14, by dionb

Posted on 2021-03-16, 22:21

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WazMeister wrote on 2021-03-16, 11:24:
Year I've opened and listened. […]
Show full quote

Year I've opened and listened.

Was getting these noises before sound card was installed, but its a ESS 1869 ESDRV GOLD16k
PSU is Samsung 103C
photos below

That's just the case of the PSU. What did you see on the inside?

Last edited by dionb on 2021-03-18, 12:34. Edited 1 time in total.

Reply 11 of 14, by mr.cat

Posted on 2021-03-16, 22:48

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WazMeister wrote on 2021-03-16, 21:01:

P.S Turn volume up to hear the weird noise.

OK at least it wasn't a fart joke 😉
Hard to say, could be fan bearings or coil whine...
What happens if you (gently) lift up the whole computer from one corner in a slightly different position? Sometimes helps with resonating fan noise.

Also sometimes I've had obnoxious noises coming from some wires touching the cpu fan, but it doesn't sound like that I don't think.

Reply 12 of 14, by WazMeister

Posted on 2021-03-17, 22:38

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No, lifting don't help... god knows!
The tone changes when using mouse too on menus and stuff

Reply 13 of 14, by weedeewee

Posted on 2021-03-17, 22:50

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Could be the capacitors in your PSU need replacing, could be the coil inside the psu has seen too much and will now sing along happily to whatever the change in load brings.
anyway, at the moment it sounds like EMI. what to do about it? play some music and turn your volume louder, get another power supply, place ferrite cores around all the power cables inside the computer...

Right to repair is fundamental. You own it, you're allowed to fix it.
How To Ask Questions The Smart Way
Do not ask Why !
https://www.vogonswiki.com/index.php/Serial_port

Reply 14 of 14, by WazMeister

Posted on 2021-03-18, 10:48

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Thanks.

Impossible to find a Psu to replace or even match this sucker.

May recap it and do that ferrite thing whatever that is.

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