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#267783 - 22/10/2005 23:21 whining power-supply
speedy67
enthusiast

Registered: 18/12/2000
Posts: 341
Loc: South-West-Germany
Hi there,

my power-supply in the central makes high whining and very annoying noise. I asked Hugo for a spare, but he has only other whining ones left. It must be a wide spread problem.

Can anyone recommend another model which will fit into the central? I'm not an electronics-specialist, so i don't want to try and error (burning down my central).

I'm in Germany, so an european seller would be great.

Thanks for any advice...
_________________________
cheers, Thomas new owner of the MK1 00123 MK2 12GB 090000815 (my first one) MK2a 040103735 (from 303) and ???

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#267784 - 22/10/2005 23:50 Re: whining power-supply [Re: speedy67]
tman
carpal tunnel

Registered: 24/12/2001
Posts: 5528
What voltages does it need? If they're the same ones as a PC then you could probably use one of those. Most PC PSUs won't work properly unless you provide a sufficient load on the output however.

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#267785 - 23/10/2005 03:14 Re: whining power-supply [Re: speedy67]
The Central Guy
enthusiast

Registered: 18/03/2002
Posts: 225
Loc: San Diego, California USA
Hi Thomas,
Do you think it is the power supply or could it be the fan? They are separate inside the Central...

Otherwise if it is the power supply, maybe something like the power transformer, that should be easily replaced...

I've never heard any noise coming from my units....

Thanks,
Randy
_________________________
Happy owner of 2 Centrals, 2 Empegs Mk2a 160GB, 1 Empeg Mk2a 60 GB, a Rio Riot, 4 Rio Receivers, and two 1GB iPod Shuffles...

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#267786 - 23/10/2005 06:36 Re: whining power-supply [Re: The Central Guy]
speedy67
enthusiast

Registered: 18/12/2000
Posts: 341
Loc: South-West-Germany
It's definately the PSU, not a fan. A PC PSU is too big, i think. The best would be if i could find the original one from an electronics-supplier. I took it to an electronics shop, but they said, they don't have anything like that. I hope, someone knows the needed specs so i can check farnell i.e.
_________________________
cheers, Thomas new owner of the MK1 00123 MK2 12GB 090000815 (my first one) MK2a 040103735 (from 303) and ???

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#267787 - 23/10/2005 08:49 Re: whining power-supply [Re: speedy67]
Roger
carpal tunnel

Registered: 18/01/2000
Posts: 5554
Loc: London, UK
Quote:
It's definately the PSU, not a fan.


Yeah, it is. It's a voltage thing, IIRC. At 110v, there's no whine. At 240v, there is. Or maybe it's a 50Hz/60Hz thing. The PSUs that we used in the pre-production units worked fine, but they changed something for the production run, and only tested it in the US.

You might be able to fix it by replacing one of the components on the PSU, but I don't know which one. My Central and the replacement PSU are in the attic right now, so I can't easily check.

Quote:
A PC PSU is too big, i think. The best would be if i could find the original one from an electronics-supplier.


I think it's a custom-built PSU. A small PC power supply ought to work, I think. Unless you also need 3.3v. I don't recall.
_________________________
-- roger

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#267788 - 23/10/2005 14:42 Re: whining power-supply [Re: Roger]
peter
carpal tunnel

Registered: 13/07/2000
Posts: 4142
Loc: Cambridge, England
Quote:
It's a voltage thing, IIRC. At 110v, there's no whine. At 240v, there is. [...] The PSUs that we used in the pre-production units worked fine, but they changed something for the production run, and only tested it in the US.

Yes. It's also related to Tman's point about power supplies not working properly if the output load is too small: at 110V input, the Central isn't too small an output load, but at 240V in the UK (and 230V in Speedy's native Germany, which incidentally I looked up in Schott's Original Miscellany, which I'll now be sending back, as it's clearly been misadvertised as containing solely useless information) the Central is too small an output load, and the PSU goes into oscillation and literally whines.

Adding a dummy load is another way of solving the problem: Richard-the-second tried jerry-rigging a big old winchester to his Central, and the power-supply did indeed stop whining, but unfortunately he couldn't find an old winchester that didn't whine worse. I think he eventually solved the problem using a bunch of 5W lowish-value resistors, but that's hella inelegant.

Peter

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#267789 - 23/10/2005 14:51 Re: whining power-supply [Re: peter]
tman
carpal tunnel

Registered: 24/12/2001
Posts: 5528
UK mains voltage was changed 230V a while ago to make it consistent with Europe. The original spec was 240V +/- 10% so we're still in that range.

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#267790 - 24/10/2005 02:17 Re: whining power-supply [Re: Roger]
drakino
carpal tunnel

Registered: 08/06/1999
Posts: 7868
Loc: Seattle, WA
If the problem only occurs at 240v, then wouldn't a power converter probably be cheeper to solve the problem then trying to replace the internal power supply?
_________________________
Tom

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#267791 - 24/10/2005 08:28 Re: whining power-supply [Re: drakino]
tman
carpal tunnel

Registered: 24/12/2001
Posts: 5528
Quote:
If the problem only occurs at 240v, then wouldn't a power converter probably be cheeper to solve the problem then trying to replace the internal power supply?

Probably but it's a tad inefficient. I've got a stepdown transformer for 110V and it hummed like crazy as well.

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#267792 - 28/10/2005 13:01 Re: whining power-supply [Re: The Central Guy]
schofiel
carpal tunnel

Registered: 25/06/1999
Posts: 2992
Loc: Wareham, Dorset, UK
No, they do whine - when we were in Alpha with it I had two replacements.

In my experience, the fan barely ever comes on.
_________________________
One of the few remaining Mk1 owners... #00015

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#267793 - 01/01/2006 17:19 Re: whining power-supply [Re: speedy67]
altman
carpal tunnel

Registered: 19/05/1999
Posts: 3450
Loc: Palo Alto, CA
The PSU just needs to supply +5v and +12v. Not too much of a tall order to find something suitable and make holes in the bottom moulding to fix it there.

ISTR the 12v is only used for the HDD/CD power and is regulated down for the audio. 4A is probably safe. 5v is used to produce the 3.3v rail and 2.0v CPU core, plus run the 5v side of the HDD/CD but again ~4A is probably ok too.

Maybe one of the mini-ITX PSUs would be suitable?

Hugo

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#267794 - 01/01/2006 17:39 Re: whining power-supply [Re: altman]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 30891
Loc: Seattle, WA
I just noticed the other day that the Central I got from Mike Schrag is whining. (Definitely the PSU whine we're discussing, not fan noise.)

If I took the PSU out of my plexiglass prototype jupiter and plugged it into that Central, would that work OK? I think Mike's central might have been a later beta unit, it's got full plastics but had hand-labeled buttons.
_________________________
Tony Fabris

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#267795 - 03/01/2006 11:39 Re: whining power-supply [Re: tfabris]
altman
carpal tunnel

Registered: 19/05/1999
Posts: 3450
Loc: Palo Alto, CA
Yep, the PSU didn't change over revisions. ISTR the PCB is badly labelled on early units (maybe gnd/5v/12v are mixed up on the silkscreen) but the wiring definitely didn't change.

Hugo

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#267796 - 03/01/2006 16:28 Re: whining power-supply [Re: altman]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 30891
Loc: Seattle, WA
Excellent, thanks.
_________________________
Tony Fabris

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#267797 - 08/07/2006 13:04 Re: whining power-supply [Re: altman]
speedy67
enthusiast

Registered: 18/12/2000
Posts: 341
Loc: South-West-Germany
Hey, i finally managed to change my whining PSU. I bought a Sunpower SPS 060-D1, which provides 5V 8A and 12V 4A, which is more than enough for the Central. Its a fanless PSU for internal use, and my Central works supersilent now.
I connected it to the HD and CD power with a Y-cable, from which i cut off one of the connectors, so i could connect the cables to the screw-terminals of the PSU.
Easy job, such a shame, that i didn't do that earlier.

cheers, Thomas

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