If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
Testing PSUs
Hello,
I've been aware for a few years that dodgy PSUs are a significant cause of hardware problems, and further particularly poisonous problems as they can be intermittent or look like something else (video/HD etc). I really would like to be able to test PSUs as although I'm not a pro I am constantly fixing people's machines. I've trawled around the web and googled the groups and I can't find an easy reasonably cheap way in which a non-pro and non-electronics bod can reasonably test a PSU for unstable voltages and other problems. (I was originally hoping that a cheapo $5 multimeter might be do the job). What I am wondering is whether it is the case that 90% of PSU problems could be diagnosed with a carefully thought out strategy with inexpensive equipment and non-pros in mind. Here's a naive illustration of what I mean : * Use easily-constructed gadget to apply maximum loads (perhaps a few knobs might be needed for differently rated PSUs). * test lines (forgive the terminology abuse) with cheapo multimeter, and a cheapo ampmeter. *Eventually remove the PSU cover and look for leaking capacitors. * Perhaps also, if multimeters can do it : set the multimeter to show the max/min voltages reached to test for unstable voltages without constant (boring) vigilance (I'm rather thinking of those max/min thermometers I've seen; don't know if multimeters can do this). I would love to be the guy to write up a web page dedicated to non-pro PSU testing, but alas I'm just a humble programmer bod. What I have seen sure ain't aimed at fiddlers like me. And yet I am salivating at the prospect as I can clearly see the value of being able to test PSUs. The idea of buying an oscilloscope and trying to follow some of the advice I've seen on the web and in these groups sends shivers up my spine, but so far that seems to be all there is. Is this idea realistic? And does anyone have any ideas along these lines? thanks, Greg |
#2
|
|||
|
|||
The cheapo $5 meter is not going to do it. You must splurge
'big time' for the $20 3.5 digit multimeter. No way around that major expenditure. Power supply must be fully loaded by computer when testing. Computer with full load (multitasking so that many peripherals are being used simultaneously) then has each DC voltage measured with that multimeter. Voltage must remain in upper 3/4 of limits per chart, provided with procedure (called '3.5 digit meter and computer load'): http://www.tinyurl.com\2musa Alternative is to purchase a large DC load, adjustable so that every DC voltage is 100% loaded, then monitor each voltage with an oscilloscope and meter (looking at both ripple voltage and DC steady state voltage), and then verify power supply still maintains these output voltages when a variac lowers AC voltage from 120 VAC to 90 VAC. Easy as hell. Getting equipment is the complex part. Power supplies must work even at those extremes simultaneously. Yet the 3.5 digit multimeter connected to a fully working computer is a second best alternative. Still none of this will verify that other essential functions are installed including EMI/RFI filtering, overvoltage, and overpower protection. Short out all DC voltages and start up supply. Power supply must also pass that test without failure. Intel defines a minimum size wire for shorting. Some will recommend a plug-in tester that does not load supply as effectively as above '3.5 digit meter and computer load' test. Plug-in tester does even less than a 3.5 digit multimeter - for almost same money. This may also provide useful information: alt.comp.hardware.pc-homebuilt entitled "Power Supply" on 5 Feb 2004 at http://tinyurl.com/32j4g Greg Lorriman wrote: I've been aware for a few years that dodgy PSUs are a significant cause of hardware problems, and further particularly poisonous problems as they can be intermittent or look like something else (video/HD etc). I really would like to be able to test PSUs as although I'm not a pro I am constantly fixing people's machines. I've trawled around the web and googled the groups and I can't find an easy reasonably cheap way in which a non-pro and non-electronics bod can reasonably test a PSU for unstable voltages and other problems. (I was originally hoping that a cheapo $5 multimeter might be do the job). What I am wondering is whether it is the case that 90% of PSU problems could be diagnosed with a carefully thought out strategy with inexpensive equipment and non-pros in mind. Here's a naive illustration of what I mean : * Use easily-constructed gadget to apply maximum loads (perhaps a few knobs might be needed for differently rated PSUs). * test lines (forgive the terminology abuse) with cheapo multimeter, and a cheapo ampmeter. *Eventually remove the PSU cover and look for leaking capacitors. * Perhaps also, if multimeters can do it : set the multimeter to show the max/min voltages reached to test for unstable voltages without constant (boring) vigilance (I'm rather thinking of those max/min thermometers I've seen; don't know if multimeters can do this). I would love to be the guy to write up a web page dedicated to non-pro PSU testing, but alas I'm just a humble programmer bod. What I have seen sure ain't aimed at fiddlers like me. And yet I am salivating at the prospect as I can clearly see the value of being able to test PSUs. The idea of buying an oscilloscope and trying to follow some of the advice I've seen on the web and in these groups sends shivers up my spine, but so far that seems to be all there is. Is this idea realistic? And does anyone have any ideas along these lines? |
#3
|
|||
|
|||
* Use easily-constructed gadget to apply maximum loads (perhaps a few knobs might be needed for differently rated PSUs). * test lines (forgive the terminology abuse) with cheapo multimeter, and a cheapo ampmeter. *Eventually remove the PSU cover and look for leaking capacitors. * Perhaps also, if multimeters can do it : set the multimeter to show the max/min voltages reached to test for unstable voltages without constant (boring) vigilance (I'm rather thinking of those max/min thermometers I've seen; don't know if multimeters can do this). I would love to be the guy to write up a web page dedicated to non-pro PSU testing, but alas I'm just a humble programmer bod. What I have seen sure ain't aimed at fiddlers like me. And yet I am salivating at the prospect as I can clearly see the value of being able to test PSUs. The idea of buying an oscilloscope and trying to follow some of the advice I've seen on the web and in these groups sends shivers up my spine, but so far that seems to be all there is. Is this idea realistic? And does anyone have any ideas along these lines? To give a power supply a test with relative inexpensive equipment is no too hard to do. You can go to some places like Digi-key and look for some low value resistors . Get a few and a few switches. You may have beter luck on e-bay finding some at a more reasonable price. YOu will need them to be in the low ohm value , around 5 ohms and less. Also high wattage. Set up a test stand and use the swithes to add more resistors for a bigger load. Look up Fluke for a multimeter. They are not going to be your run of the mill $ 10 meter. They make some that will recorde the highest and lowest voltages. While outside of your price range they also make a solid state recording scope of sorts. I use one at work from time to time and they are nice to have if you can get someone else to pay for them.. |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Testing a power supply | JJ | General | 2 | November 4th 03 10:14 PM |
Mushkin Level II Dual Pack Testing Troubles | Rick | General | 5 | October 19th 03 08:36 PM |
Testing AIO Printers | JD | General | 0 | September 6th 03 10:25 PM |
Testing Modems | DBBS | General | 0 | August 30th 03 02:11 AM |
Store testing RAM | S.Heenan | General | 2 | July 21st 03 01:10 AM |