On Sunday, August 23, 2015 12:14:58 PM Mick wrote: > On Sunday 23 Aug 2015 01:11:03 Fernando Rodriguez wrote: > > On Saturday, August 22, 2015 3:19:50 PM Alan Grimes wrote: > > > Isn't this the filthiest oscilloscope u've seen recently? > > > > > > The only bare metal contact that I could safely use to get a reading off > > > was a +12v line on a spare PCI-E gpu plug. The ground reference is the > > > chassis. > > > > > > You can see the machine's settings in the photo clearly enough. The > > > waveform is fairly constant, it stays in this mode most of the time but > > > sometimes goes into a "low ripple" mode where the ripple falls to +/- > > > 20mv and holds tight. The scaling indicates the upward spikes are around > > > 0.120 volts and the downward spikes are about 0.22 volts. This > > > __SHOULD__ be within the input tolerances of the motherboard's > > > regulators. > > > > Regulators don't filter noise, they introduce it. Capacitors do that as > > somebody pointed on the other thread. > > > > So if you're on a tight budget and you have an electronics surplus store > > nearby you can replace all the capacitors on your mobo and PSU (except the > > big bulky ones on the PSU) for about $3. > > It is quite likely that only the secondary circuit on the PSU needs to have > its electrolytic capacitors replaced. We're talking of anything between one > to half a dozen of capacitors. In all likelihood less than a $1 to $3. If > any are even slightly domed I'd start with those and spend no more than a few > cents. > > Primary circuit ceramic capacitors (transient protection) could have been > affected if the PSU was submitted to high surges in the mains supply. I had > one go bad on me after sheet lightning hit the area once. Its replacement > along with a resistor fixed the PSU without any further problems and to much > of my surprise - I thought it was a gonner! > > Domed capacitors on the MoBo is a different story. Quite likely other > components would have been affected and many of them are surface mounted. > You'll need a magnifying glass and steady hands for those. It is not > something I would attempt in haste, as it is easy to damage more components > than what you fix on a MoBo. YMMV.
I don't think it's very likely to have damanged something else if it's just noise, but then again I'm not an electronics engineer, this is just a hobby of mine so you may be right. Though I can tell you that I have gotten a few damaged boards to work like new by just replacing the electrolitic caps. > PS. Noisy PSUs are nothing new. The noise is can be caused by the capacitors, > or the coils. Although annoying it does not necessarily mean that there is an > electrical problem with the components. If the fan is rattling, then a drop > of oil on its bearing should soon put a stop to this. As Dale mentioned, a > stalled fan will not help the longevity of the remaining components. :-) Agreed. -- Fernando Rodriguez
