renovationism

While doing some work at a client site the other day, she told me that one of her computers was experiencing blackouts several times a day. I felt the case and could tell it had a serious fever. It can be difficult to hear breath sounds on newer PCs with variable speed fans, but after opening the case, it was clear the fan was breathing its last breaths. The patient was overheating, and its thermostat was shutting it down.

I instructed her to leave the case open and point a fan towards the innards. That stopped the blackouts and confirmed the diagnosis. Surgery was needed to replace the power supply. One call to Dell and $97.63 later, and the new organ was on its way.

In the olden days, PCs were held together with thousands of tiny screws: tedious, but easy to identify. These days, many makers use finger-operated latches to give easy access. Few tools, if any, are required. The downside is that sometimes the latches can be difficult to identify. In this case, the side cover is loosed via the latch on the top rear of the case.

Inside, it’s pretty standard. In the body cavity below, the object in the upper left quadrant is the CD/DVD drive. Below it and out of sight is the 5.25″ floppy drive. The lower left quadrant is the braincase: buried in there is the Intel CPU, which runs pretty hot, so it’s got a heat sink and fan attached to it and is encased in a plastic duct that directs air past it for cooling. The lower right quadrant is the hard drive. And in the upper right quadrant is the power supply we need to replace.

Below is the new power supply (PS). I had looked at the model number on the old PS and tried to find it on the Dell website, but no luck. So I called support and gave them the PC’s serial number to place the order. The new part looks right, but, to make sure, I checked the new part number against the original one. They weren’t exactly the same, which isn’t a surprise, but they were close, and the input and output power numbers on the sticker matched, so I felt comfortable we had the right part.

Below is one of the two blue latches holding the hard drive in place. Just press and remove. Anything this color inside the cavity is a latch that releases something.

Since the PS extends under the CD/DVD drive, I started by loosing it…

…and then lifting it out of the cavity. The gold Ribbon cable carries data from and to (in the case of a writeable device) the CD/DVD drive. I was hoping I could just leave the gold cable in place.

Next, I unlatched and pulled the hard drive out. It has two cables attached to it. The blue one carries the data to and from the drive. The red/yellow/black bundle that runs to the power supply is – you guessed it – the hard drive’s power cable. With gentle pressure, it’s easily disconnected from the hard drive.

The following picture shows a big colorful cable bundle running from the power supply to a white connector that’s plugged into the mother board. However, the gold CD/DVD cable is in the way. Guess I’ll need to disconnect the CD/DVD drive anyway.

With the gold CD/DVD cable disconnected, the big power connector is accessible. There’s a little plastic latch on the side of the connector that releases it.

Three screws through the rear of the case hold the power supply in place.

Below, the power supply is out, but not completely disconnected. We’ve disconnected one power cable that ran to the hard drive and one that ran to the mother board, but you can see another one, a yellow and black bundle, running from the PS to the mother board. You can also see that I’ve pulled the floppy drive (laying to the left of the carcass, but still connected), in order to get my fingers on all those cables. With all the major organs pulled, the mother board is almost completely exposed.

Once the third and final power cable is disconnected, the old PS is free and can be recycled via your friendly neighborhood electronics recycling program. Don’t throw it in a landfill!

To close, just reverse the steps:

1. Place the new PS in the cavity and fasted it with the three screws
2. Connect the two power cables to the mother board, and the third to the hard drive
3. Put the floppy drive back in place
4. Re-connect CD/DVD drive’s gold cable to the mother board and put the drive back in place
5. Put the hard drive in place
6. Put the side cover on

This entry was posted Monday, March 16th, 2009 at 9:51 am and is filed under tech. You can leave a response, or trackback from your own site.