Leviton HCS10 X-10 switch repair

My front porch lights stopped working some time ago. Today I was able to narrow down the fault to the Leviton HCS10 X-10-controlled wall-switch. The relay in the switch was clicking, but no power was coming out on the blue lead.

Figuring I had nothing to lose, I decided to attempt to repair the module. They’re bloody expensive. Even if the repair failed, I’d still get to look around inside.

It should go without saying, but in this litigious world, it does not: doing this may burn down your house. Or it might electrocute you. It will definitely void your warranty. Do not do this if you are someone who doesn’t know a diode from an op-amp. You have been warned.

HCS10It was not easy getting the thing apart. Popping of the switch plate is easy, it’s just four plastic tabs. The rest of the job was very difficult, however. It appeared to be held together by eight screws, four on the front and four on the back. But turning the screws had no effect. I was able to turn them, but nothing came apart. In the end, out of sheer frustration, I just put a soldering iron onto the screw head, and melted it apart. BUT DO NOT DO THIS! There is a better way, which I discovered too late.

The trick, which would have saved me a lot of time had I realized it earlier, is that the screws are all reverse-threaded for some reason. Too keep people out, maybe? But then why use a standard Phillips head? A tamper-resistant or one-way screw might have worked better.

Anyway, inside the module there are two PC boards, mounted in a plastic frame, and connected together by a SIP header. I used my multimeter to probe around. I found that the blue controlled lead did have a good connection with the relay. But no connection from the black “hot” lead to the relay. I couldn’t see the PCB tracks that should have been carrying the power, they were apparently under the relay. I had to remove the relay to trace the connection back from there.

To remove the relay, it was necessary to separate the two PCBs. This required desoldering the SIP header that connects them. It was not easy, even with the help of a vacuum solder-sucker. They never get out all the solder. I had to keep pressure separating the boards (bending them, even), and then go back and forth with the soldering iron on the header pins. On each pass across the header, a little bit more pin comes out. With much patience, the boards come apart eventually.

Probably easier, if you have a spare SIP header of sufficient length, to just cut the old one with wire cutters and replace it later.

With the two PCBs apart, it is then possible to desolder the relay, which is much easier to desolder than the SIP header.

Broken trackWhen I removed the relay, what did I see under it? A broken trace!

That’s the track that carries power from the hot lead to the relay. No wonder no power was coming out.

I fixed the broken track by soldering a bridge of wire across the gap. Replaced the relay, reassembled the module PCBs in their frame, and tested again on my bench. Working!

Putting the entire module back together wasn’t entirely easy, because I had melted it apart. But I was able to melt it back together again. Would have been better, if I had known the screws were reverse threaded, but there it is. It seems reasonably solid, anyway.

Replaced the module in the wall, and now the porch lights work again.

1 Response to “Leviton HCS10 X-10 switch repair”

  • I’m imagining a blog entry soon…”Rebuilding your home after your X10 Leviton repair job didn’t work” or “Boy, the fire department came to my house quickly”…

    Perhaps it’s prudent to figure out why the trace burned out in the first place? Fixing it with a wire jumper gets it working again — terrific, but what caused it to melt down in the first place? Can you be sure it was by chance?


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