Information below from :

RF PCB from Top View:

RF PCB from Top View:

K3 Schematic:

U12 and U13 Parts Placement:

27 June 2022.

Stephan von Sprinfield:
01. Have the K3 bottom Plate removed for accessing the RF PCB Solder Side, by your VHF Transceiver.
02. Have the K3 Power Supply nearby, with access to an AC Outlet.
03. Have a DVM and respective Leads available.
04. Have at least one (1) Alligator Jumper Cable.

Below are a Full Path Schematic of the Voltage Input and Power Switch Circutry; a RF PCB Solder Side Photo of J30 - the Interface from the Power Switch and its associated Transistor to the RF PCB.
and finally, a Perspective Snapshot of the Voltage Path Components.We will attempt some troubleshooting via 2 Meters.

Power ON OFF Schematic.

RF PCB Solder Side J30 Photo.

Perspective Snapshot.