Greetings!
Washington 5-pin style is a pretty old radio, at least they haven't made them in a while.
So that tells me that there may be a parody of problems that are adding to this scratchy effect...
Several things may add to what you're experiencing now...
- Dirty Mike Switch - did not know that Cobra made a "Dynamite" brand in their DYNAMIKES' line - but I' not surprised - especially if it hasn't been used in a while and operates poorly - or it's just an unpopular mike for similar reasons...
- Capacitors that have failed - they separate STAGES OF AMPLIFICATION (AMPLIFIERS) so they are no longer keeping the bias of stages separate so you have an "overamplification" of one section working into another.
- Dirty potentiometers - damp moist humid storage areas accelerate oxidization and corrosion - long term storage period - or lack of use - could explain the sporadic problems...
So - lets step back a moment...
If that is you only mike you got to use, it may be the sole problem or not, the QUANDARY is; we cannot verify it is the problem - not without another donor to check if the problem is a bad microphone switch - or a bad mike...
Usually these things come with a STOCK 5-pin microphone - so if it's got one that would help us in figuring out the scratchy effects...
Tearing apart a radio only to find out it was due to a bad switch - and it was not the fault of the radio - it was the microphone all along and all you needed to do is wire one up to check ... it is just not good karma...
Ok, got a friend with a similar 5-pin radio so you can take the microphone over there and check for scratchy using that one?
Else the radio will have to go on the "Bench" get torn apart to clean connectors and potentiometer controls - that can get expensive...
Let us know what you find...
Regards
:+> Andy <+: