|
I got a copy of the Sams from Just Radios and I am glad I waited to get it as it clarifies alot of stuff. The picture on the front shows a different style radio than mine but there are a couple different models that this Sams covers so that is not too surprising. The chassis and controls look identical so I am quite sure that I have the right one.
I had assumed that the PS filter (which is CLCRC with field coil as L) would use the caps in 10-15-15 order. It turns out it is 15-10-15. It shows the rectifier as a 5Y3 but I am almost certain that it was a 5U4 that I pulled out of it. IIRC the 5Y3 has more voltage drop so I may need to procure one especially since the line voltage is higher these days. The 6F6 output tubes had been replaced with 6V6 however so will have to check the plate and screen voltage ratings as the 6V6 may be able to handle the higher voltage.
The document also has pretty detailed alignment procedure in case I end up needing it. It is interesting (I have never done an alignment) that the first step has the generator set at 456KC and the tuner tuned to 1600KC. In the procedure they specify a dummy antenna value. There are three different loads used; 0.1uf, 200pf and 400 ohms. I assume this means that you disconnect the antenna and replace it with the specified component. Is that right?
Interestingly no mention of the AVC in the alignment procedure but for the voltage map it states that AVC should be made inoperative (doesn't say how, I guess experienced tech knows how) and bias provided by 3V battery. I guess I need to trace out the circuit and figure out how to do that.
Another interesting fact is that all interstage trannies (coils) are fixed with a separate parallel variable cap. To this tyro this seems like a nice sturdy design.
mike
|