[MrFixr55]

Hi Hamiton,

If you get half of a post from me, fear, not, I will complete it. My computer mouse has lost its mind!

OOps, read my post, then reread yours.



Are you talking about the screen grid voltage being the same as the plate or the control voltage being the same as the plate. If you are talking about the Screen grids of the 42s, this is normal! These tubes are connected as Triodes on the 650. The screens are tied to the plates on all 3 42s (the "driver" and the 2 "Push Pull" output tubes), therefore the screen and plate voltage will match on each of the tubes. the "control" grids" (the input to the tube) should be at a negative voltage, especially for the driver) when measured against chassis ground. If the control grid was at plate voltage, the plates would glow red, melt, blow the output transformer, etc.! the Screen/plate voltages on the 2 42s that are output tubes should be the same.

If you rewired the speaker wiring, recheck it. If you miswired, you may have B+ directly to one output tube through the field coil, 1 leg of the output transformer on the other output tube and the other leg of the output transformer feeding B+ (modulated by the output transformer) to the rest of the radio.

With the power off and unplugged and the filter caps discharged, you should get 350 Ohm between the plates of the 2 output tubes. If you get more like 1.5K Ohm then it is miswired.

After correcting, if there are still issues, see the rest of my post.

Try this "divide and conquer" technique:
1. Power down the radio.
2. Remove the grid cap connection from the "75" detector / 1st Audio tube.
3. Power up and allow 1 minute to warm up.
4. Touch the grid cap of the 75. You should receive a very loud hum, especially if your house wiring is not armored cable and you have old school fluorescents in your house.
5. If you get the hum, troubleshoot the RF, IF, detector, volume and tone control circuits and recheck wiring. If no hum, troubleshoot the AF section (1st AF, Driver and output stage).

There are 2 or 2 caps around 50 -110 pF between the detector and 1st AF. If these caps short, this will kill the sound but you will pass the "Hum" test as described above.

Most of my radios have a "phono" jack installed, either from the factory or added by me. This way, if I don't like what I am picking up on AM or want a cleaner, more "HiFi" sound, I can play an MP3, FM Tuner or computer through the radio and call up an "old time radio" (OTR) website or channel, or pipe the Big Band channel from the cable company through the radio. The amplifier in this radio should be a real good performer!