[Boatanchors] Comdel CSP-11 Speech Processor

[David C. Hallam]

I am trying to repair a non-working Comdel CSP-11 speech processor. For 
those of you not familiar with it, it is an external speech processor 
made in the 60's or 70's that used RF processing to improve the average 
to peak ratio of speech.  It converts the microphone audio to a SSB 
signal, processes it through a limiting amplifier, puts it through a low 
pass filter and product detector to recover the audio, and then a final 
low pass filter.

I get no output from the processor.

The first stages of the unit are working.
Audio amplifier
Local oscillator
Balanced modulator
USB filter

At this point the signal is passed to a limiting amplifier.   I get an 
18.3 KHz usb signal at the input of the limiting amplifier.  I don't 
really know what I am looking at on the scope at the output of the 
limiting amplifier so I can't tell if that part is working properly or 
not.  Does anyone know about limiting amplifiers and can offer 
suggestions about what I should see.  There is a manual and schematic on 
BAMA.

No one at Comdel seems to know that Comdel ever made a speech processor.

David
KW4DH

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Alexis de Tocqueville