Roland CR-5000 & CR-8000 Switch Cleaning

Roland CR-5000 & CR-8000 Switch Cleaning

Brad Williams

Introduction

I have taken on the repair of two Roland CR-5000 drum machines. Each with their own flaws, one with a poor attempt at DIY switches and the other with unresponsive stock switches.

Since this post is about how to clean the stock switches we will focus on the latter. 

I would recommend only to do follow through with this cleaning if you have 2+ hours of time to dedicate. It's important to get this right the first time to avoid having to tear it all apart again. 

Necessary Tools/Consumables

Procedure

These were completely unresponsive when pressed, all of them reading 300kOhm/OL on my multimeter.

The difficult part about replacing stock switches is removing the metal spacing bracket and each switch. The metal bracket is soldered in at each end and each switch has 4 soldered pins.

The procedure is..

  1. Remove solder from all switches using a solder pump and then wick up what remains.
  2. Remove solder each pillar of the spacing bracket.
  3. Gently remove each switch by pressing in the tabs on either side using a flat head screwdriver ad prying upwards. Ensure the switch pins are not still bonded to the mounting hole by pressing in the pin with the soldering iron. After all switches are removed carefully pull out the bracket by nudging each end. 

The fun part

After removing the bracket and switches, its time to disassemble and clean each switch. 

The switch works by pushing a plunger with a conductive contact across two metallic contacts which are each connected to a pair of legs below the switch. The switch stops working because the metallic plates and contact become dirty and are no longer conductive. In the microscopic image, its clear that the right contact is covered in muck. The left one is not in good shape either..

  1. Open up the switch
  2. Spray some DeoxIT D5
  3. Scratch off the muck from the contact and plunger head
  4. Wick up excess with lint free cloth

Even after cleaning and verifying the switch works in the unit, when pressed it measured 3-10kOhms of resistance. This must be enough for it to work, so I continued with the rest. Many of them were absolutely caked with junk and needed a serious cleaning. In total it took me 4 minutes per switch to thoroughly clean.

After putting it all back together, we can only hope our cleaning was adequate. I discovered that one of my switches, despite cleaning, had no continuity. I was able to swap in my adapter board and get it working. I prefer the feel of the adapter board switches and the 3D printed cap blends in extremely well.

 

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