The HG should provide a very strong fundamental tone at 1 mHz,? especially when the box is removed from the chassis and powered. . Its not uncommon for the crystal to fail. The HG output is at a very low level, a spectrum analyser? is handy here. But, any SW radio placed near will find the harmonics from 1 to 35 megs as you tune up and down the spectrum... use SSB if you have it. thats where those small Chinese radios are handy for this. There is little to check in there really. The two diodes clip the oscillator output giving the distortion to create the harmonics, I guess these could fail, but doubtful.
