Reference: Input power pins for MST motors, PowerGrip, ESM motor, and EBM camera

Jason Thompson · August 20, 2021

Roughly a year ago, my brother and I reverse-engineered wiring for his Bolex 12V motors and cameras. I'm posting the details here as a reference

We reverse-engineered replica PowerGrip batteries with 10 x 4/5A 2100mAh Ni-MH cells and 2" outside diameter NuTone 3808 central vacuum pipe. In my opinion, it's better to plug a cable into a 12V Li-On battery pack (like JuiceBox) or a battery belt. ??‍♂️

MST (6-pin)

Requires a 6-pin female Tuchel connector (Amphenol T 3401 XXX). Pins 4/5 are ground. Pins 1/2 are +12V.

I recommend putting a switch in-line to control on/off. For the in-line switch to work, you will need to bypass the front MST button by putting a jumper between the two remote pins on the back of the motor.

MST (7-pin)

Requires a 7-pin female Tuchel connector (Amphenol T 3476 XXX). Pin 2 is ground. Pin 5 is +12V.

I recommend putting a switch in-line to control on/off. For the in-line switch to work, you will need to bypass the front MST button by putting a jumper between the remote two pins on the back of the motor.

In theory, you can bypass the front MST switch without using a jumper by using pin 3 for ground; however, the MST circuitry was not designed for this path to carry that kind of current. It will eventually burn a trace off the circuit board inside, causing smoke to pour from the motor. We know this from experience (and fixed the traces on two MSTs with wire).

PowerGrip

Requires a 7-pin male Tuchel connector (Amphenol T 3475 XXX). Pin 2 is ground. Pin 3 is +12V.

If you are connecting the other end of your cable to a 4-pin XLR 12V power source, please ensure there is no battery inside the PowerGrip when you connect!

If I recall correctly, you can connect the other end of your cable to Ni-Cd/Ni-MH battery charger output to charge a battery in your PowerGrip.

ESM (3-pin)

Requires a 3-pin female Tuchel connector (Amphenol T 3261 XXX). Pin 1 is ground. Pin 3 is +12V.

I recommend putting a switch in-line to control on/off; otherwise, the ESM always runs when connected to power by this method. The 3-pin circuitry bypasses the ESM front on/off button.

ESM/EBM (7-pin)

Requires a 7-pin male Tuchel connector (Amphenol T 3475 XXX). Pin 4 is ground. Pin 3 is +12V.

I recommend putting a switch in-line to control on/off; otherwise, the EBM will always run when connected to power. You can control the ESM with the front on/off button although it may be more convenient to use an in-line switch instead.

My brother made a quick demo of his EBM using a 4-pin XLR power cable with in-line switch on Vimeo.

I hope that helps! For now, I sell these cables (except for the ESM 3-pin) for those not interested in making them.

Edited August 20, 2021 by Jason Thompson
formatting

Jason Thompson · August 23, 2021

FYI, the pin numbers are with respect to the soldering side and not the typical user side.

Bob Seiboth · December 4, 2023

Hello,

Has anyone ever worked with the EM motor? Wasn't planning on using sound so this seemed like a good alternative but I can not locate the connectors. The 4 pin power connector has the 4 pins in a square format, while all the Amphenol connectors I've investigated have the 4 pins in a more trapezoidal shape (I didn't do well in geometry; the 2 upper pins are closer together than the 2 lower ones...) - Here is a pic of the EM connector - No manufacturer data on the plug. The bakelite piece is ~ 11.6mm diameter - Any suggestions?? I have one cable complete that came with the motor (no battery), but need a panel type connector for a DIY battery pack.

Jason Thompson · December 8, 2023

Robert Ditto tells me the original EM had the same 4-pin Amphenol-Tuchel connector as the EL and MM. Based on that, I'd say your EM has been modified. See the attached photo.

Bob Seiboth · December 9, 2023

Thank you Jason, that explains it. I wondered myself if that might be the case since the 3 pin remote connector looks almost like a different manufacturer. This EM motor came with a cable with the same mystery connector on both ends so I could probably replace one cable end with a 4 pin XLR and be done. Now I need to find the pin out so I don't blow anything up...

Appreciate you taking the time to look into this!

All the best,

Bob