I am in need of a Crystal for a Collins 75A4 that I am restoring. It is the 20 meter crystal "Y4" 16.5 MHz or Mcs. I know that there used to be a couple of companies that manufactured replacement crystals. I can get the old one to oscillate but it is 5 kHz off in frequency. It will not pull down enough, it quits oscillating. Tnx es 73 Price W0RI