2011年3月15日 · is a 6U7 as specified in the schematic... but on the socket voltages page, it shows the RF tube as a 6K7. I also notice the non-code 125 version of this radio has a 6K7 RF amp. Is there any important difference between the two tubes? -are they directly swapable? (New word for the day. ) Nelson

Hope some smart person can help with this question and I hope I am smart enough to describe it correctly on my R111. Since the motorboat sound stopped when I remove the 6U7 IF tube, I have been checking that socket area and I see 1/3 watt brown, green,brown silver resistor-150 ohms. It is connected to pin 8 of that tube.

I still have teh antenna switch in the A position. I only gt a buzzing sound at pin 3 plate with the tracer. I next put the sig gen on the grid cap of the RF 6U7 tube and get a weak tone at 600 on rhe radio dial which where the sig gen is also set to. As I tune aroun the AM dial, I also get a loud clear tone at 900KC and approx 1350KC.

I was not able to hear a tone at the grid of the RF 6U7 using my tracer. I did have the sig gen set at 600KC, grounded to chassis and the hot lead of the gen connected to the RADIONET terminals and to chassis connectors. I then moved to check the plate of the RF 6U7. At the plate of the RF 6U7 tube, I get 266 VDC when measured to ground.

2011年1月7日 · If I'm reading the drawing correctly, it'll pass the current associated with the plate and screen of the 6A8 and first 6U7. It supplies the screen current for the 2nd IF tube, also. When I permanently replace it, I'll use a 2W.

I then connected a 47PF cap to the positive lead of the sig gen and connected it to the grid cap on top of the 6U7 tube. I then connected the sig gen negative to the ground terminal stamped in the radio chassis. I then went to the bottom inside of the chassis and put the signal tracer to pin 3 (plate) of the 6U7 tube socket.

2006年6月13日 · I was checking the tubes on my 38-3 and I find that a 6K7 is being used for what the schematic says should be a 6U7. It is the RF tube. I looked in my tube b…

2025年2月16日 · If the above audio test shows audio stages work, select for radio operation, & pull the 6U7 RF tube. Problem still heard in the speaker? Replace that tube & pull the 6K8 converter tube. Problem still? Replace tube & move to the next, 6U7 IF tube. Repeat this process for each stage up to the 6Q7 AF preamp (the one whose grid connects to the vol ...

2025年3月7日 · That is a wrong tube and may behave differently. 78 is equivalent to a 6K7, 6D6 is a 58 is a cranky 6U7. from memory one is a sharp cut of pentode the other a remote cut off pentode. It would be pertinent to use the right one.

Interesting enough, it shows that each tube could act slightly different even though both tubes were NOS RCA 6U7 tubes in original boxes. Now I guess I am going to restart the alignment process.---John