Dell T620 Power Interface Board that won’t power up

I recently acquired a Dell T620 chassis that included everything except a motherboard and power supply.  I had an extra motherboard already, so I installed it only to find that it would not turn on.  The 12V_AUX LED on the motherboard would light up, but when pressing the power button it wouldn’t do anything.

I started debugging by swapping components from another chassis I had, at first thinking it was the frontpanel, switch, or maybe a bad cable.  It turns out that it was the power interface board (PIB) itself.

The board appeared to be in good shape, with no obvious scratches or parts missing.

It was time to get out the microscope and do a closer inspection.  Since there aren’t a lot of parts on the board it didn’t take long to find a suspect problem.  One of the parts appeared to have a solder bridge between two of the pins (6 and 7).

A closer look at the pins:

All it took was removing this solder bridge, and the system then powered up without any further problems.

I have no clue how this would have ever worked in this state, so I’m not sure how it even made it out of Dell’s factory.  It didn’t appear to be reworked based on my experience, so this is a very strange escape.

Either way, I was able to rather quickly find the issue and fix it, saving the need to purchase a replacement.

Building an Outdoor Gate Sensor

With wireless door sensors becoming inexpensive, it would be nice to have one that can work in all elements.  I found one that has the ability to hook up an external dry contact sensor, but it was still only rated for indoor use.  To deal with this, I built an outdoor enclosure to house the wireless receiver, and used an external magnetic reed sensor on the gate.

For the housing, Lowes has an outdoor-rated plastic box by Taymac.  The box comes with three openings and a few fittings and covers.  A multi-size pack of glands was from Amazon.

In my case, I didn’t want to use any of the included holes, and instead wanted to use a separate gland.  The covers have slots for flathead screwdrivers, so a gland wouldn’t make a good seal.  Given the Taymac boxes only come with two covers, I also needed a third cover (also found at Lowes).

I also used a piece of unopen corrugated tubing which covers the sensor wires.  

I then drilled a hole to fit the gland.  

Unfortunately the mounting end of the gland was pretty short and couldn’t be secured with the locking ring, so instead I used epoxy to secure it in place.

The sensor is mounted by drilling a hole through the board close to where the gate hinge is.  Near the hinge, the door won’t swing much relative to the hinge so there’s no need to worry about the wind causing it to send false positives.  

The magnet that activates the switch is mounted to the door.  There are spacers to ensure the magnet is mounted close to the switch when it is closed.

From there, the assembly can be mounted to the fence so wiring and sealing can be completed.  The box is mounted so the gland is higher than the sensor so water wouldn’t flow down into the box if any did manage to get into the tubing.

From there, I attached the sensor to the electronics.  Then I used sealant to cover all the mating interfaces as an extra measure to make sure it is water-tight.  This includes around the tubing/gland interface as well as in the end of the tube where the wires exit.  It looks messy, but it will help seal things.

After the sealant has set, the electronics can be assembled and the door can be tested before placing the cover on the box.

Testing confirms it works well, and doesn’t falsely trigger when I shake the gate.  

Final assembly.  As you can see, it’s next to the wall of my house so I couldn’t hide the box around the corner easily.  It will need to be accessed to change the battery occasionally.  This is mounted behind the entrance, so no one should mess with it, though I might still tack down the cable so it’s not hanging out as much.