The day my PC died.

I can picture myself there in the call center taking the call - "Oh, so your system will not boot and you think it is dead? I'm so sorry to hear you are having that problem, but let's see what I can do to help you. First of all, have you checked that the power cable is plugged in? It is? Has the system ever worked? It has? Do you remember if you were doing something unusual just before this happened, like installing new hardware or software? Nothing? Well in that case, what we are going to do is send you another motherboard and see if that fixes your problem..."

My system was old, and out of warranty, so contacting the vendor was not going to be very helpful. Instead, I went to my local computer store and bought a new motherboard with new processor and new memory. I also bought a new power supply. I installed everything and tried to boot it up. Nothing happened.

Investigating the power supply

I had a hunch it might be the power supply. I consulted my two favorite hardware manuals, "PC Hardware in a Nutshell" by Robert Bruce Thompson, Barbara Fritchman Thompson, and "Upgrading and Repairing PCs" by Scott Mueller. I checked out what they had to say about power supplies.

Essentially, they both said about the same thing - that power supplies are an often overlooked source of PC problems and that the problems they cause are typically hard to diagnose. Conclusion, as far as I was concerned: it made sense to spend enough money to get a power supply that was capable enough that it would be safe to rule it out as the source of any remaining problems.

Problem solved

I had bought the least expensive power supply (ca $30) and I now upgraded it to one that cost three times as much. I installed it and tried again. The system came up. Problem solved. Thanks, Robert, Barbara and Scott!

So who was right?

As a technical support employee, I would have replaced the motherboard, which is also what the computer store technician had suggested.

What was wrong with this advice? Nothing, or everything, depending on where you are coming from with this problem.

A vendor who supports their own hardware can be expected to have made sure that the various parts in its system will work together. In such a situation, you have some assurance that the power supply will be strong enough to bring up the system. If the system is within warranty and has not been changed significantly, there is no reason to suspect the power supply.

But if a retail customer, such as myself, puts together a system from components off-the-shelf, there is no guarantee that the power supply will be sufficient. This was precisely my situation.

There is also another point to consider. In troubleshooting a system as a technical employee there is a danger in relying too much on the specifics of a particular case, since you have no way of knowing how honest or accurate the information from the customer is. Call handle time standards and service level agreements further restrict you in this regard, so you typically have to do what makes the most sense in a majority of similar cases.

As to why my old system failed, I don't have a definitive answer. It was probably not because of the power supply. I tried the new power supply with the old motherboard. It still would not boot. I suspect the old power supply, while probably sufficient to boot the old system, was still inadequate after years of upgrades of memory and peripherals. That too stresses all other components.

It is not worth pursuing the matter any further now that the new system is up and running.

Update some six months later:

I have become convinced that it was an old, erratic hard disk that was the culprit. After not having used it since the old PC died, I connected it to my new system for the first time. For the first time, my new system is having problems reading from the floppy drive. The old hard disk also gets noticeably hot. I decided to not take any more chances with that disk. Having lost one PC to it, I did not want to lose another one to it.

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