How to modify the Marantz PMD221

NOTE: I provide information as to how I preformed this modification, but I do not support nor suggest any modifications. You preform modifications at your own risk to your body and your property.

This is a guide/report of my research as to how to modify the Marantz PMD221 to allow for motor speed to be variable during recording. The first thing I wanted to do was get a look at the bottom, so I looked at the Marantz PMD221 Service Manual to see what I was about to unscrew.

I could see that there were a few different screws on the bottom.  I like to keep bags from kits/parts orders for this purpose.

I grabbed my screwdriver set, chose the appropriate tip, and got to work.

You can see that I organized screws with labels from the service Manual.

In this recorder, Pitch adjustment is available during playback, but not during Recording. This solution adds a second 1K pitch control that is not bypassed during recording. I added two wires, one to one side of a resistor pad, and one to the lug of the existing pot. This mod allows for a good range of motion, but at the lower range, the motor pauses – that is probably not good, so I have to remember not to sweep that low. A low level resistor should probably be added between the green wire and the wiper (middle lug) of the potentiometer – If I have time I may experiment with it.