[GreenKeys] CV-89 Refurb Project

[N4BE_Jim@yahoo.com]

Have begun a refurb on this CV-89, which is more or less running after replacing a blown power supply rectifier tube.  Now I can't get the narrow discriminator to balance per the maintenance manual.  The scope "looks" OK when tuning a narrow shift signal otherwise.  Testing with an audio generator connected directly Z-103 (the narrow discriminator filter), the low tone output is about double the output of the high tone filter output, which accounts for the imbalance.  The filters do resonate at the correct frequencies however.  

Z-103 appears to be a sealed potted box containing the two filters for mark and space.  I am thinking that the filter has an internal failure, meaning either I open it up or find a replacement.  

What say, any CV-89 parts out there?

Tnx, Jim N4BE

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