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Growing up quick...with a 38-690xx Pics added.
#35

OK.. I subbed in a resistor for the choke so I could do some more testing. Theres no reception on any band. I injected a signal directly at the grid of the 6A8 tube and it plays through the set but VERY weak and garbled. I did the "touch" test with the other grid caps and listened for a scratch or pop noise from the speakers but no dice. I then went for the throat and injected signal at the grid of the 6F6 and voila, it plays through beautifully. So I have some work to do. I will work my way backwards through the stages and see where the signal shows up. The volume control does not have any noticeable affect on the volume level until its turned all the way up and then its only marginal. Something else I noticed is the field coil on one of the tweeters gets a bit warm after about 10 minutes of testing. Its not hot, just warm. The other field coils are nice and cool. Another thing that comes to mind is that the characteristic noise of switching between bands is not present. I swing the switch and shes silent aside from the hum of the resistor substituted for the choke. I did voltage checks and they all seem to fall in line with recommended levels in the RCA manual. There was no voltage present on any pin of the 6J5 AVC/Bass Amp tube in the amp chassis. It looks to be wired as a diode on the schematic I believe. Sorry, I know I bounced around a bit but thats how the info came to me as I type this at work. Any help is greatly appreciated.
On a side note: This radio sounds GREAT! I know I was kinda cheating by putting signal to the driver tube but she sure does sing none the less!


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RE: Growing up quick...with a 38-690xx Pics added. - by badwaxcaps - 02-26-2013, 10:30 PM



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