Power supply problem?

[glatt]

Originally Posted by BigV

You mean a power switch built into the side of the power supply itself, the side the power cord connects to... Yeah.. I've seen those. in your case (ha no pun intended) you did exactly the right thing.

That's exactly what I mean. I was about to get out the dremel tool to cut the metal case to accommodate the power supply switch, but then I figured that would scatter little conductive metal filings all over the motherboard, so I used snips instead.

[Undertoad]

now not only does it work, but it's badass.

[zippyt]

Good Job Glatt !!!

[tw]

Originally Posted by glatt

Turns out I either don't know how to use my auto ranging meter, or it's crap. It won't settle down on a known value even when I try it on a working battery.

So I wen old school and just bought a cheap analog meter from Radio Shack.

An analog meter is best relocated to a bin. Meter must be digital.

Now, assuming those numbers were from a digital meter, well, a power supply is actually two supplies. One to power a system that says even when the CPU can execute. It had to measure 4.87 or higher. A number determined, in part, by how a digital meter operates.

A defective supply can still boot the computer. Also important is to confirm purple, red, orange, and yellow wire voltages on the new supply after installed. Others have seen resulting failures even months later that could have been identified long before its warranty expires.

Best would be to return the analog meter. Then buy a superior product from Wal-Mart. Or even a $5 meter from Harbor Freight. Analog meters are useless. See that number 4.87? Analog meter cannot measure to three digits.

Back to the auto ranging meter. What does it measure for a 9 volt battery? It may have been bouncing because that was your problem. A failure that might have been identified even months ago when a defective supply was still booting that computer.

Best is to confirm voltages on all six wire are now correct. Identify a failed supply months or a year before it causes computer crashes.

[glatt]

Originally Posted by tw

Back to the auto ranging meter. What does it measure for a 9 volt battery?

I was really frustrated with it, so I tested it on a 6 volt lantern battery. It was bouncing around at almost zero volts the entire time. And I think it settled down at around zero volts for that good battery. I was certain I had the dial indicator set for reading DC voltage. This same meter works fine with AC home electrical service voltage when the dial is set to the AC setting. It's made by Extech and cost me around $40 several years ago. I think I hate auto ranging meters.

When I used the old school analog meter on the 6 volt battery, it read something like 5.5 volts. And I also used the old school analog meter on the outlet, and it read around 115v.

The computer works now, and it would be a hassle to unplug the cables, pull it out from under the desk and take the measurements you are suggesting. Plus, I'd feel the need to buy a third meter, because the analog one is admittedly not so accurate. (But at least it works and is exponentially more accurate than the auto ranging one I own.)

[tw]

Originally Posted by glatt

I was really frustrated with it, so I tested it on a 6 volt lantern battery. It was bouncing around at almost zero volts the entire time.

Meter may not have been on its DC settings.

An autoranging meter will default to measuring AC voltage. A 6 volt battery measured on an AC setting would bounce about until it settled at zero volts. Something to check before binning that meter.

Analog meter may be good for harsh environments such as modifying AC house wiring. Measuring a battery for life expectancy. Or learning why/if a car battery is defective. Keeps an autoranging meter from falling into a car's radiator fan. Then you do not have to use words not found in the dictionary - such as "whoops".

[glatt]

I was thinking about this today, so tonight when I got home, I really took a close look at the auto ranging digital multimeter. It turns out one of its fuses had blown. So it could measure temperatures just fine, and could measure household AC current, but couldn't measure DC.

[HungLikeJesus]

You're getting to be an electronics genius!

[tw]

Originally Posted by glatt

It turns out one of its fuses had blown.

If you accidentally measure voltage with the 'current' setting, then a fuse will blow to protect that meter from you. Many failures are directly traceable to humans. I know this to be true due to multiple examples. But the most common reason for failures is manufacturing defects - which may explain your power supply.

[glatt]

Oh, yeah, I probably put the probes in the wrong hole one time.

Frustrating thing is I can't find the fuse at either of the two radio shacks in walking distance. I found one online at an electronics supply place, but it's $6 with $12 for shipping and handling. I can't bring myself to pay that much for a part that should cost a quarter. I should just buy a new multimeter.

[HungLikeJesus]

Maybe you can replace the fuse with a .22 shell.

[tw]

Originally Posted by glatt

Frustrating thing is I can't find the fuse at either of the two radio shacks in walking distance.

What is the fuse (Amps and three letters that define its characteristic - AGC, MDL, GMA, etc)?

[glatt]

5 mm x 20 mm
GFE CQ
10A 250V

[tw]

Originally Posted by glatt

5 mm x 20 mm
GFE CQ
10A 250V

Don't know why it is a GFE. A GME or GMA 250 volt fuse is similar; should be sufficient. Those should be available even in Lowes.

Important is for that fuse to be a fast blow type and 250 volts. If 10 Amp is not available, any other value even down to 2 amps should be more than sufficient since only the current measuring functions would be affected; would blow that fuse. During voltage measurements, the meter would not even draw 0.001 amps.

[ZenGum]

Originally Posted by tw

If you accidentally measure voltage with the 'current' setting, then a fuse will blow to protect that meter from you. Many failures are directly traceable to humans.

Glatt, you're Top Management!!! Congratulations, you brain-dead MBA parasite bean-counter.