Logitech Harmony 200 Repair

For some time, my trusted all in one remote control was having problems. Some buttons were not working very well : the “Watch TV”, “TV” and “left”.

The “Watch TV” required very high pressure, and the two other where not working about half of the time, independently of the pressure on the button.

For the “Watch TV”, after testing the contact directly on the pads of the remote, it was clear that the problem came from the black conductive pad on the button. Its resistance was much higher than the other ones. The solution was easy, cut it and replace it with one borrowed from an old phone in my junk hardware stock. The main problem I had was to make them stick together. Initial attempt with neoprene glue was a failure. The material is a kind of silicone, and I guess that it does not work with this kind of glue. I ended by using double sided adhesive tape.

The other buttons were working with the remote disassembled. Maybe the cleaning was enough, so I reassembled the remote. All was perfect for a few days, then the problem on the “TV” and “left” buttons reappeared. Cleaning was not enough.

It took me some time to figure out the problem. Measuring the voltage between GND and the pad seemed good: about 3 V on the top pad, and 0 V on the bottom pad (same on all buttons). Measuring the voltage between the top and bottom pad was inconsistent. It was very low on the non working buttons. So, there is certainly a continuity problem on the bottom pad.

The problem with the PCB is that a lot of tracks are masked by the black material used as contact for the buttons. But, when looking at them with a magnifier, there is a slight square which I think correspond to the connection with the copper pad underneath. So we can guess where they connections are made.

I tried to follow the tracks of the problematic buttons, and I found that they were connected by the same track, and that there is a loss of continuity in the blue portion on this picture:

Making contact with the top pad of a non working button with the test point just at the end of the blue section make the corresponding key working. I also found that bending the PCB a little made the button working again. There is no visual evidence of a cut track, but for me it is the only explanation of the problem.

To fix this, I scratched a little area of the solder mask of the track at the beginning of the blue sections, and soldered a thin enamel wire to the test point just after the blue section.

Now my remote is working perfectly again !