Roland Space Echo RE-301 - Motor On/Off Switch Mod

[clarisso11]

Hi everyone,

I've recently finished restoring a Roland RE-301 unit that was in bad shape. I noticed that there is no way to turn off the motor and use the Reverb and Chorus effects on its own, and started thinking about adding an On/Off switch for the motor.
I couldn't find any instructions online, although from what I have read, people have done this mod successfully. I used to have a Watkins Copicat with separate motor switch, which disconnected the ground to the motor - would it be as easy as that?

I have attached the schematic for the power supply circuit that controls the motor (here is the full service manual: https://www.synthxl.com/wp-content/u...vice-notes.pdf).

Does anyone know where to start with this mod?

[clarisso11]

I realized I didn't provide much explanation along with the schematic. Here is the same schematic, with some annotations.

Essentially, the motor speed control consists of IC4 and a number of FETs (Q100-108). I'm hoping that there is a way to insert a simple toggle switch to make or break one of the connections between the motor and the PCB. Since I'm not too familiar with brushless motor designs, I don't really know where to start, and what to avoid to prevent damaging anything.

Hope someone can help!

[dmeek]

A switch in series with F3 will stop the motor and release the pinch roller.

[clarisso11]

A switch in series with F3 will stop the motor and release the pinch roller.

Thank you so much, I will give this a try (although I have no doubt it will work)!

[clarisso11]

I've just finished the mod and it works great! I cut the trace on the diode side of F3, and inserted the switch there. I ended up reusing the "Echo - Single Delay" toggle switch since I never used that anyways.

One thing to note is that the switch turns off the background light of the VU meter together with the motor, but the VU meter still works as usual, so I don't mind.

Thanks again dmeek !