Ok, for one or two people out there who may have been following me on the latest GRC-9 adventure wanted to post an update and a question. Four sets came in, three US and one Frenchie. Two of the sets are done, cleaned up, calibrated and all that sort of stuff and are ready to go. But two are still on the bench. One transmitter has a band switch that refuses to work and the other a Cincinnati Electronics receiver has an issue with backlash. This appears to be the newest receiver and works well except the receiver has an issue with backlash when tuning. On AM it’s no problem, espicaley with the huge Barn Door wide IF in that receiver but with no separate BFO you have to use the tuning control to set the beat note in CW, its important because with a wide IF and high gain receiver in the CW sub band you can often hear two or sometimes three stations at once so having the ability to set the pitch of the note is important. Would have thought that maybe it’s just the design of that radio but the other receivers have good response on the tuning, even the French receiver. So, I cleaned the drive gears, lubricated the bushings that support the main drive shaft and the ball bearing on the tuning capacitor but still have the backlash issue. There are just two gears, the main drive shaft and the gear on the tuning capacitor but it’s like I have too much of a load on the capacitor or maybe excessive gear ware or something that I don’t understand going on here. Any ideas on what I should be looking for? Is it possible that Cincinnati Electronics just built these things this way? Anyone else had this issue with that receiver?

 

Ray F/KA3EKH