I have a Roland HD-1 V-drum kit that is about 15 years old. It was sitting for years when I got it, and when I put it all together it was clear that the pedals were not working. Boo! Time for a repair.
Roland HD-1 Pedal Hammer under a Heat Gun. |
How the HD-1 pedals work
With the Roland, a pedal actuates a variable resistor. When you step on a pedal, it presses on the variable resistor. Putting force on the pedal reduces the resistance of the resistor. A little force results in a small decrease in resistance. A high amount of force greatly lowers the resistance. The HD-1's computer detects this and makes the appropriate sound.There are two important parts to this mechanism: the electronic resistive strip, and a rubber hammer which presses on the strip in a variable way.
There is no internal difference between the left and right pedal. The guts of each pedal is identical.
Where it goes wrong with age
Looking at mine, the problem was with the aged rubber hammer. Originally the hammers were very flexible, but with age they became very hard, and therefore stopped pressing on the resistive strip. That led to poorly functioning (or non-functioning) pedals.
My variably resistive strips were fine and did not need replacement. I'd keep the original resistive strip in place unless it is damaged or very worn out.
Repairing the HD-1 pedal hammers
The solution is to use hammers that are as flexible as they were when new. I softened my hammers up using a heat gun set at 250 ºC. After 5 minutes in hot air, the hammers became much softer. Surprisingly, they remained soft long after they cooled. I guess that's the magic of this class of material.
The central hammer surface [marked up here in orange] variably presses on the resistive strip. No flexing means no change in resistance. |
Reinstalling these softened hammers with a small amount of silicone grease on the mating surfaces fixed the problem.
Heating the hammers may be a temporary solution, as the hammers might harden up in short order. A longer-lived solution may be to buy replacement hammers. I bought replacement hammers on Amazon, as noted here.