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On Sunday 23 Aug 2015 01:11:03 Fernando Rodriguez wrote: |
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> On Saturday, August 22, 2015 3:19:50 PM Alan Grimes wrote: |
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> > Isn't this the filthiest oscilloscope u've seen recently? |
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> > |
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> > The only bare metal contact that I could safely use to get a reading off |
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> > was a +12v line on a spare PCI-E gpu plug. The ground reference is the |
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> > chassis. |
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> > |
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> > You can see the machine's settings in the photo clearly enough. The |
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> > waveform is fairly constant, it stays in this mode most of the time but |
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> > sometimes goes into a "low ripple" mode where the ripple falls to +/- |
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> > 20mv and holds tight. The scaling indicates the upward spikes are around |
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> > 0.120 volts and the downward spikes are about 0.22 volts. This |
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> > __SHOULD__ be within the input tolerances of the motherboard's |
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> > regulators. |
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> |
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> Regulators don't filter noise, they introduce it. Capacitors do that as |
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> somebody pointed on the other thread. |
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> |
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> So if you're on a tight budget and you have an electronics surplus store |
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> nearby you can replace all the capacitors on your mobo and PSU (except the |
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> big bulky ones on the PSU) for about $3. |
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It is quite likely that only the secondary circuit on the PSU needs to have |
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its electrolytic capacitors replaced. We're talking of anything between one |
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to half a dozen of capacitors. In all likelihood less than a $1 to $3. If |
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any are even slightly domed I'd start with those and spend no more than a few |
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cents. |
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Primary circuit ceramic capacitors (transient protection) could have been |
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affected if the PSU was submitted to high surges in the mains supply. I had |
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one go bad on me after sheet lightning hit the area once. Its replacement |
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along with a resistor fixed the PSU without any further problems and to much |
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of my surprise - I thought it was a gonner! |
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|
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Domed capacitors on the MoBo is a different story. Quite likely other |
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components would have been affected and many of them are surface mounted. |
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You'll need a magnifying glass and steady hands for those. It is not |
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something I would attempt in haste, as it is easy to damage more components |
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than what you fix on a MoBo. YMMV. |
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PS. Noisy PSUs are nothing new. The noise is can be caused by the capacitors, |
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or the coils. Although annoying it does not necessarily mean that there is an |
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electrical problem with the components. If the fan is rattling, then a drop |
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of oil on its bearing should soon put a stop to this. As Dale mentioned, a |
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stalled fan will not help the longevity of the remaining components. :-) |
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-- |
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Regards, |
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Mick |
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