Changing the Icom PS-125 Mains Voltage Setting

by Maurice Nunas VEMN

Fig. 1: The Icom PS-125.
Fig. 1: The Icom IC-PS125 Power Supply.

The PS-125 power supply comes in two versions, one for 100 -120V mains (The Americas/Japan) and one for 200 - 240V (Europe/Asia). The nameplate on the back panel specifies which version you have. Changing over from one mains voltage setting to the other is simple.

First remove the black covers, revealing the inner aluminium case. There are black screws holding these covers on both sides, and on the top and bottom.

The inner case is made up of two halves, one forming the bottom and one side and the other forming the top and the other side. Look carefully. You want to remove the one that exposes the top of the printed circuit board. Remove the appropriate self-tapping stainless-steel screws to do this. You cannot damage anything if you take off the wrong panel; you will just have a lot more screws to put back.

Refer to Fig. 2. Near one end of the PCB you will see a black jumper wire and two posts, one marked 100V and the other marked 200V. The only difference between the 100 -120V and 200 - 240V units is this jumper. To convert from 120V to 240V mains voltage, simply move the jumper from the 100V to the 200V post, and reassemble the PSU.

Interestingly, after we made this change we found that the PSU would provide its rated voltage regardless of whether it was plugged into 120V or 240V mains. It provided enough current when powered by 120V to drive our IC-756Pro II to 10W RF output. We did not test beyond this; we figured that the jumper must be there for a good reason!

Fig. 2: PS-125 interior view.
Fig. 2: PS-125 interior view.


Fig. 3: 110-220V jumper detail.
Fig. 3: 110-220V jumper detail. Photo courtesy PA3DUV.
Copyright  2005 M.Nunas VEMN. All rights reserved.
Page creation, editing and photos except where noted: A.Farson VA7OJ/AB4OJ
Last updated: 09/25/2019.

Expression Web 4