Bad Membrane Buttons

The black and white piano-style switches used to change sections and tracks have a high failure rate in this product. When in proper working condition, the switches should work like a membrane keyboard on a computer, remote control, or calculator.

Using just enough light pressure to make the switch snap down, the switch should pass a signal. If the switch snaps down, but does not pass a signal, or requires extra pressure to pass a signal, even after the snap, then your switch is bad.

I am not an electrical engineer, but here is what I have observed: Inside, these Alps-brand switches have a grey rubber/silicone dome with a black carbon puck that snaps down onto the metal contacts at the base of the switch. What happens is the carbon puck goes bad from wear or old age, and either stops conducting current, or has such a very high resistance, that you have to mash the button down hard, in order for the resistance to drop to a level where the Rm1x can detect a signal. You can use a multi-meter to check continuity and resistance, to see this in action.

A switch that stays open when the rubber dome snaps down is faulty. A switch that has an initial snap-down resistance of over 500 Ohms is bad. A good switch will have a resistance of ideally under 100 Ohms or less. Anything between 100-500 Ohms is questionable. With normal pressure, new switches can have a resistance of around 30 Ohms.

When you order new replacement switches, make sure they aren't junk switches that sat too long in a warehouse. Some online sellers sell junk switches. Get a multi-meter and check every single switch for proper operation. If they don't operate like the switches found on a calculator, remote control, or membrane computer keyboard, ask for a refund or replacement. Do not attempt to install faulty or questionable switches, because you will be doing all that soldering work a second time!

The easiest way to remove the switches from the board, is from the top side of the board (the side that the component is on). I used electrical flush-cut pliers to cut all of the 4 pins, as close as possible to the plastic body of the switch. After cutting, the switches can be removed easily, and the de-soldering of the cut pins can begin. This requires at minimum, a manual de-soldering pump, and a temperature-controlled soldering iron. De-soldering braid will not be enough to safely remove the remaining pins. The pads and traces on these boards can get lifted very easily, so work quickly, with the lowest temperature that will effectively heat the solder. The process should take 3 seconds for each pin. Move on to de-soldering another pin of the next button to allow the board to cool down in each switch area, then go back and forth until all pins are removed, and until all the soldering holes are clear.

If you were sold Alps-brand switches, the new switches should snap in place, and then you can solder them in. You should aim for a soldering time of 3-4 seconds or less, with the lowest soldering temperature you can get away with. Aim to reduce heat stress the best you can, solder quickly with a well-tinned tip, and let heated areas on the board nearby cool down.

Once everything is soldered in place, use a multi-meter to check for proper switch function and continuity, and check every single solder joint you worked on.

When you put everything back together, you should have a playable keyboard that works like new!

Bad Metal Snap-Dome Buttons

The remaining switches, that are not membrane style, also have a high failure rate.

Using just enough pressure to make the switch snap down, the switch should pass a signal. If the switch snaps down, but does not pass a signal, or requires extra pressure to pass a signal, your switches are bad.

Some people recommend replacing these switches with new ones, but these boards are relatively delicate, and solder pads lift very easily. If you decide to replace the entire switches, a vacuum de-soldering station or a vacuum de-soldering gun is a must.

Before you decide to replace the switches, consider spraying all the switches with Deoxit D5 and operating the switches many times. After reassembly, the switches were worse than before, but after the Deoxit evaporated after a few weeks, it got my switches working perfectly again.

Yellowed Plastic Button Covers

The white keys on the Rm1x yellow with age, just like on many white plastics. There is a process called "Retro Bright" or "Retro Brite" that uses a combination of hydrogen peroxide, sunlight, and heat, to return the white keys to nearly their original color.

The white lines on the knobs yellow, too, but there is no way to de-yellow them without messing up the black plastic. Replacement knobs could be ordered instead.

Do not Retro Bright any black plastic, or you will get a marbled effect that will not come off.