I am trying to repair a Mirage KP-2 series mast-mount 2M preamp. It is quite old. Also, I have the companion bias-tee or Control Box as Mirage calls it.

It comes in a black plastic box with the hardware to mount it on a mast. Testing indicates the relay works and some transistors have a voltage. Unfortunately testing also indicates its an attenuator. I think it has a blown gasfet.

The small round gasfet has 4 leads and has the following markings on top:

K183 R 43

The PCB is marked KP1&2 Rev B. The Have any of you repaired a KP-2 2M preamp?

Do any of you have a schematic diagram of this preamp?

Do any of you know the part number of the gasfet transistor? (I'm thinking its the problem)

Any help would be appreciated.

Thanks & 73, Larry W7DGP