The control Master 20 is excellent. I use a lot of them. They are easily serviced if not functioning by an electronic repair service. The tamper proof screws can easily be removed by using a rotary tool to slice a straight screw driver slot in the head of the tamper proof screw and replace it with a conventional sheet metal screw before taking it to a service center. Use a short sheet metal screw, some of The locations of The screws can be close To AW NUTS!!!
MRC formerly had Doug, an excellent CM 20 service person but since he left the new folks are rather rude they will not service earlier power packs and only want to sell you their latest, greatest , $$$$$ power pack. They even told me the earlier packs are not repairable which is flat out false information.
The hand held units can go bad. I find them on 0 scale yard sale. The CM-20 pack series with a fan take a different hand held than the CM-20 packs without the fan.
With so many folks desiring the magic of digital control these MRC power packs and hand held controllers can be picked up for minimal cost. Conventional control is still a strong 0 scale 2 rail power.
The MRC 6200 power pack and the 9000 and 9500 are also great 0 scale power packs. Again, minimal cost.
If you are using MTH 2 rail Proto Sound locomotives you can simply use your existing DCS system.
If conventional control of 2 rail Proto Sound locomotives is desired in addition to non PS locomotives I would suggest to use a d.p.d.t. toggle to switch back and forth between the CM-20 and the Z-1000 for conventional power. Conventional Proto Sound works best with a MTH Z-1000 in my world.
I have pairs of CM-20 and Z-1000 set ups through out my RR. I can walk around the layout and use local panels to control a train in that town.
