I have used a Yaesu G-5400B controller box with my KenPro KR-400 elevation rotor for years at Field Day. You must add a 100uF capacitor between elevation terminal pins 4 and 5 on the back of the Yaesu G-5400B control unit to control the KenPro elevation rotor. The capacitor can be placed inside or outside of the control box. For convenience of removal, I chose to wire the capacitor externally and tie-wrapped the "FLUX" capacitor to the AC cord (picture attached). If you can see the picture, you may get a chuckle on how I labelled the capacitor. That always makes a great conversation piece at Field Day when explaining how signals get into space...

Yaesu decided to move the capacitor from the Yaesu G-5400B control box to the elevation rotor housing. This is the reason the Yaesu G-5400B control box does not work with the KenPro elevation rotor. The Yaesu G-5400B controller does not contain the 100uF capacitor and the KenPro elevation rotor does not host the capacitor either. Whereas, the Yaesu elevation rotor does have the capacitor installed inside of it.

The KenPro KR-400 is well known to have melted motor windings if the motor is allowed to run to the limit and the motor is not turned off. There are no limit switches to protect the KenPro motor. The limit switches were added to the Yaesu elevation rotor design. Back in the 1990's, I rewound the melted motor coils by hand. I would not recommend this unless you know what you are doing or you like to tinker.

I have repaired the 5V regulator, coils, OpAmps, the transformer, and some lights on the meters over the years. Concerning the transformer, I actually used two separate transformers purchased from Radio Shack to provide the 2 voltage outputs at a fraction of the cost compared to the supplier. Both replacement transformers fit perfectly inside the control box. Radio Shack was such a great source of inexpensive parts to keep my Yaesu and KenPro Az/El rotors working. I really miss Radio Shack for the convenience.

From: Nick via AMSAT-BB <amsat-bb@amsat.org>
Sent: Sunday, January 7, 2024 3:53 PM
To: amsat-bb@amsat.org <amsat-bb@amsat.org>
Subject: [AMSAT-BB] Kenpro KR-5600 Control Box Compatibility

Hi all,

I have a Kenpro KR-5400A Rotator system (KR-400 Azimuth Rotator, and KR-500 Elevation Rotator) and unfortunately the elevation side of the KR-5400A Control box is not working. I have been looking for a replacement KR-5400A control box with no luck yet but have come across a few KR-5600A Control Boxes for sale; my question for anyone that knows, is the KR-5600 Control box compatible with the KR-5400A Rotator system? To my knowledge the only difference between the KR-5400 and KR-5600 rotator systems is that the azimuth rotator on the KR-5600 is a KR-600X which is a slightly stronger rotator and it has limit switches where as the KR-400 rotator does not have limit switches in the rotator. I know that the Yaesu control boxes will not work with the Kenpro rotators without modification due to the starting caps being in the rotators rather then in the control boxes for the kenpros.

Thanks Nick KE8AKW