[amsat-bb] Landwehr 2m Preamp Help/Info & Manual Request

I recently obtained a Landwehr 2m preamp which I plan to use for AO-7 operation. The preamp did not come with any significant documentation besides what is printed on the cover (and thats a bit faded).

The preamp appears to be functional, except that it has a tendency to switch back and forth between RX and TX by itself (when no RF is present and the PTT is not connected). This has made the preamp unusable. Does anyone have experience with this preamp and/or know how this issue can be resolved?

I am looking for any suggestions as well as any documentation (manual/schematic) for this preamp that you might have. Your help is appreciated.

Thanks & 73,

Doug, KD8CAO