A Reminder about PSU Dangers and Liabilities

[KeriJane]

Hello.

I regularly come to this thread and am continually struck with Awe in the face of all the remarkable Talent, Knowledge and inventive Genius displayed by many of the Regulars.

Whether it's a mere re-cap or re-fan, a complete overhaul or in many cases a complete re-design of a PSU, the Power Supply Design and Troubleshooting section of this Forum demonstrates a COLOSSAL amount of technical know-how and ability.

But....

This post is NOT intended for the highly talented likes of Everell and company (you know who you are) who know the risks, but for the multitudes of readers that may be tempted to carry out these modifications and improvements for themselves or especially for others:

Modifying or even opening up a PSU for inspection can leave you LIABLE FOR DAMAGES if something should go wrong and either:

• Damage the Computer or its Data
• Cause damage to building Wiring
• Cause damage to a building such as a Fire

This is especially relevant if you repair or modify a PSU for someone else or are a Renter and damage occurs to someone else's property.

It doesn't even have to be your fault. If any argument can be made that you may have caused a catastrophe, you will likely be sued for damages. Even if the person you repaired the equipment for doesn't want to sue, their insurance company will.

This is more relevant to PSU repair because even a "Gutless Wonder" could potentially handle enough power in the primary side to start a drapery on fire or damage inadequate house wiring or even an extension cord.
Also, remember that nearly ALL Computer PSU's nowdays have standby power on 24/7 and some have badly designed 5vsb circuits. If you modify or repair, it's your baby!
eMachines HAS Liability Insurance and a bunch of Laywers. Do You?

In Court, the fault is hardly ever found to be the Homeowner or Renter.
They would just love to find someone to sue and that would be US, as the last person that worked on the computer that MAY have started the blaze.

Unlikely, I know but something to keep in mind during these litigious times.

Play Safe,
Have Fun,
Keri

PS. This thread is meant mainly for Residents of the USA, Land of the Trail Lawyers and Home of the Lawsuit. Others should keep their local regulations in mind.

[370forlife]

Re: A Reminder about PSU Dangers and Liabilities

This is true. A power supply has enough juice in it to kill you, your pets, your hardware, maybe chuck norris, and burn down your house very quickly.

If you decide to work on a power supply, make sure you know what you are doing, and to take all the correct precautions. Know your way around a power supply. Can you put that there? Will it still work after wards, or will it blow up? I did that with my yuelin when I put a new transformer in it. Nobody had done it before and I didn't know what was going to happen, and it worked. But I always tested it outside on the concrete plugged into a GFCI plug. Always keep in mind power supplies can hold a lethal charge for a while, I always let my psu's sit for hours before pulling the pcb back out to work on unless I haven't fired it back up. Hell, my yuelin sat for about a year before I got it...lol.

Just always test it first. I ran that yuelin for about 40 hours on a old p3 board sitting on a concrete floor in the basement with nothing flammable near it, just to make sure.

And always, ALWAYS, be sure of your skill if you are going to fix someone else's power supply. You are not going to be there to monitor it, be able to hear all the little clicks, pops, and strange things going on with the computer. Make sure you know what you are doing so nothing happens to their computer.

Fixing things will always make more problems.

[ratdude747]

Re: A Reminder about PSU Dangers and Liabilities

yes. if you are not an expert, follow these rules for opening psu's

1. only open a psu that will turn on. (and that you dont mind voiding the warranty on)

2. unplug the psu

3. let it sit for 10-20 min, so the primary caps discharge.

4. open it

5. do not mess with it without SPECIFIC instructions from an expert. taking pics is fine. if you see bloated/leaking caps, do not run it with the cover off. if you run it cover off, keep hands AWAY from the unit- thats lethal juce running it.

6. if you have questions, post them in the psu forum.

[KeriJane]

Re: A Reminder about PSU Dangers and Liabilities

Hi Ratdude!

Even "Just Looking" or fixing a very minor problem has its risks.
Here's a sample from another thread:

ust thought I'd let you know about a problem I had with a new Enermax Galaxy 800W. Out of the box, the PSU shut down (with diagnostic indication on the rear LED) due to the fan not working. I decided to open it up (voiding the warranty) because it was fairly obviously just the fan that was at fault, and I didn't have the time to wait for a replacement. The fan wires were bundled with the output cable and the cable ties were attached in such a way that the wires to the fan connector were under tension and the connector had popped out. Simple I thought - just plug it back in, put it back together and job done!

So I did that, connected it back up and BANG! Blown mains fuse, house circuit breaker trip, head in hands. I opened it up again and discovered that the mains common mode choke had come into contact with a stud at one end of the nearby heatsink. The heatsink is connected to the negative end of the rectified mains, so it was a virtual short through the rectifying diodes. :o(

I checked the diodes (there are two bridge rectifiers in parallel, so fairly beefy). The choke was slightly damaged but OK. I found a suitable piece of plastic to put in as insulation and powered it up again. All OK this time.

I must have disturbed the choke slightly when opening the unit up, but there was nothing to prevent the contact. Looks like a design flaw or manufacturing error - the choke could come into contact with the stud at any time if, for example, it was joggled around in transit. Maybe there was supposed to be an insulator there and someone forgot to fit it.

Now, if this well-meaning soul had repaired this PSU for someone else and the house burned down...... OR if his/her apartment is damaged....
Guess who gets sued?

The sloppy manufacturer?
NO.
Whoever broke the "Warranty Void if Broken" seal gets sued.

Even if all you did was take pictures.

Oh Well,
Keri

[ratdude747]

Re: A Reminder about PSU Dangers and Liabilities

hmm... even i would overlook that. whoops. have a mod delete my post.

[Wizard]

Re: A Reminder about PSU Dangers and Liabilities

Ratdude, I was spoken with people regarding this liabilities.

And I can say:

Patching a power cord is big no no.. for example and have to use strain-relief, safety parts.

Doing mods outside of bulletins is a risk without UNDERSTANDING and KNOWLEDGE.

And I have to repair circuit boards in CRT TVs as they have tendency to occasionally roast huge area of PCB into carbon (most common cause is bad solder in circtical area (especially horizontal circuit where yoke, fly, deflection caps, coils and pincushion are and runs at high KHz and at high current, up to 1.6KV tend to arc and slowly fry while TV kept going with noisy picture eventually fail. I had to grind this out and do flying wires (not flimsy, heavy gaunge stranded) and replacement components in exact original configuration since the component were also destroyed in this frying stage.

Also I have to make sure repair and other items that was not repaired are properly dressed/not touching, not frayed and any specific items that is loose tied up with zip tie per original design, if component is installed sloppily as orignal, reinstall it correctly and resoldered if it is going to touch anything else for example.

Finally, the PSU is designed to MINIMUM specs, not over specs. That's the key, reason is they tend to blow up or go out of regulation/noisy at 100%. Most especially the transformer and transistor and their driver circuit.
All the main power transistors have different drive requirements means drive circuits is different to meet reliablity and efficiency, safety.

It is rather like the horizotal transistor so strict and narrow area that voltage, current drive, B+ at specific voltage, design of flyback transformer and drive design.

It is too involved and best thing is just replace the components and if this works. If not, replace PSU with another if it is not in possession of your stuff. That includes your family, clients. This is to protect yourself.

Use correct fuse as specificed.

Cheers, Wizard

[JSWashburn]

Re: A Reminder about PSU Dangers and Liabilities

Hello.
They would just love to find someone to sue and that would be US, as the last person that worked on the computer that MAY have started the blaze.

Unlikely, I know but something to keep in mind during these litigious times.

Thanks for the update Keri. Reading your post was quite a reality check. No doubt PSU's are some serious devices. In fact, I'm attempting to repair one of my own (for personal use).

I'm going to mark my unit as "BAD! Do not use" should it ever end up in the trash. I sure would hate for some poor SOB to use and/or mess with it 3rd hand.

Given the economic condition everyone is going through, you can bet those litigious bastards (lawyers) are hungry for blood and on the look out for a feeding frenzy. And remember folks. They are also aspiring politicians who know all too well how to eff your world.

[Gianni]

Re: A Reminder about PSU Dangers and Liabilities

A power supply has enough juice in it to kill ...., maybe chuck norris

ROFLMAO!!!

Gianni

[kc8adu]

Re: A Reminder about PSU Dangers and Liabilities

around here the fire dept incompetence would spoil any evidence at the scene.
a friend nearly lost his grandkids to a walmart plastic fan.lasko was ordered to recall them but the word didnt get out.
the fire it started gutted the room where the kids had been sleeping just minutes earlier.fire dept stated the fan started the fire but then shoveled it and the other debris into the dumpster!spoiled the evidence the insurance co could have used to subrogate the claim and recover damages from lasko.
i bet a lot of fires of "undetermined origin"are caused by both chinese junk and "back alley patch job"repairs.
i have seen quite enough.
as for liability after repair first it will be hard to prove who did what and the condition of many electrical items is poor after the event.
then the evidence gets mishandeled.
very hard to prove.
in many many thousands of items i have repaired i have never had anything i repaired go nuclear.
but i shitcan anything i deem dangerous due to its condition or design.

[Toasty]

Re: A Reminder about PSU Dangers and Liabilities

>>I'm going to mark my unit as "BAD! Do not use" should it ever end up in the trash.<<

10# sledgehammer - saves ink.