[Wswss] Boonton Peak Power meter

[Bill Janssen]

I have a Boonton peak power meter that I think is broken. If so I would 
like to
repair it (if possible). The model number is 8900B.
Does anyone have a schematic or know where I can find one?

I attached a Scope (required) and can see the input wave form but is 
very weak. I assume
that there is a diode detector somewhere inside. I think I know how to 
operate this thing
but it is not working as expected

Bill K7NOM