Thanks Franco for the info I had thought about the using the 8640 as the crystal as you suggest so will give that a try. I think that the crystal is used for aligning the 160M band and since I dont work that band (no antenna) I can probably skip that step.
The Drake alignment instructions are set up for those that do not have any test equipment so you use the crystal calibrator to align the 50Kc IF and the BFO. Since I have the right test equipment I am trying to determine when I can use it instead. There is plenty of noise at my QTH so I would expect some change in noise level or some change in the way the audio sounds but nothing it is as if it is totally out of the circuit but I will leave that for later. Still trying to determine the correct voltage for the BFO collector, not sure if it is supposed to be 12vdc or 10vdc. Since it is not identified on the schematic I have no idea what it is supposed to be. It can effect the amplitude of the BFO signal and consequently affect the product detector performance. From looking at other Drake products like the 2C and the 4C I am guessing it should be 10vdc. Steve NU0P -----Original Message----- From: iz oos [mailto:[email protected]] Sent: Saturday, July 11, 2009 5:32 AM To: steve white Subject: Re: [Drakelist] R-4b Alignment and troubleshooting help Hi, I am not an expert of the R-4B as I had not been that luck to find one so far. However, As for point 2. I would try to connect the signal generator to the crystal socket. Actually, between the generator and the crystal socket I would also place a small isolating hf transformer (something like a 1:9) for isolation and likely a better match. As for point 4. I would not be that sure that you should hear a change in the audio in the case there is no noise to blank. Owners of the R-4B will tell you something about that. 73 Franco IZ2OOS 2009/7/11 steve white <[email protected]>: > Hi All > > I have a nice R-4B that works and am now trying to get it perfect. I have a > couple of questions that I think you guys know the answers to. > > 1. What is the voltage that should be athe collector of Q6 the BFO. I think > based on looking at other Drake schematics that it should be 10 volts but > there is no mention of this in manual anywhere. I am seeing about 11.6 > volts here, is this an issue that I need to worry about? > > 2. In the alignment section of the manual section 6.4.6 it asks you to plug > in a 12.6Mhz crystal and I don't have one of those. Is there another way to > do this step without having that crystal? I have an HP8640B rock solid > signal generator. > > 3. My R-4b does have one problem and that is that the audio sounds hollow > when I tune in CW signals. Putting a scope on the audio out the trace looks > just fine. So am mystified by this. Any ideas?? Have replaced C173, C90, > C11, C192 and C176 already. > > 4. The noise blanker appears dead, absolutely no change in sound at all when > I turn it on. Have not yet begun to trouble shoot that section. Any advice > on the Noise Blanker would be great. > > Thanks for any help. > > Steve NU0P > > > _______________________________________________ > Drakelist mailing list > [email protected] > http://mailman.zerobeat.net/mailman/listinfo/drakelist > _______________________________________________ Drakelist mailing list [email protected] http://mailman.zerobeat.net/mailman/listinfo/drakelist
