I also realized that I am overhauling a GE console, and it had a hum after re-capping. Trying the line cord both ways in the outlet made no difference. I added a three-wire power cord, to ground the chassis, and that eliminated all the hum. I have added grounding cords to my public-address amplifiers to get rid of hum and "tingles" when you touch the chassis, as well. My set did not have any line-to-chassis capacitors.
Don

Can I add a grounded cord to this set I always hear that you can't ground these radio chassis

Your set has two .01 MFD capacitors on the input, one from each line to chassis. This puts 60 volts AC on the chassis, a good source of hum and tingles. I highly recommend a grounded power cord, and then you could remove those two capacitors, which may be in a tar block.
Don

Yes, you can add a three wire cord. It's a transformer powered set. Do yourself a favor and also add a 2 1/2 amp agc fuse and holder. Black power cord lead to the end of the fuse holder and the ring to the on off switch or transformer. White goes to transformer and green to chassis ground.


Hope this isn't a dumb question but I can't help wondering about the speaker.
I know you said it was stock but it doesn't look stock.
If memory serves, I think this model may have used an electrodynamic type speaker with a
field magnet instead of a permanent magnet and if it does and if it's a replacement speaker, it may not have a bucking coil. Look to see if there are two extra contacts on the speaker that appear to be in series with the voice coil. It should be wound around the electromagnet and allow any voice coil movement caused by hum to create a 180 degree out of phase signal that cancels any voice coil movement created by the field coil, hence, cancels any hum.

I just went an looked up the drawing for the set on Ryders and it shows that it is suppose to have one.
Also, what I hear on your recording sounds like 120 cycle hum but it's hard to tell.

If it is 120 cycle hum it's power supply created. It's hard to tell from the recording.

If it's 60 cycles, then the guys are right about it being a possible filament 60 cycle ground loop.

Anyway, I may be barking up the wrong tree on the speaker but it's a tree that's really easy
to eliminate buy a quick look.

Best,
Pete

it for sure a field coil speaker it had the ohms written on the coil too that matches the schematic must have been the way it looked on video, and ps i have been trying all the options none seem to be helping so far One of my test voltages are low the first power test from ground point C to point B is 160 volts it should be 200v I have replaced all the things it says cause that except the output xformer

Maybe I am mis-reading something. It doesn't look like point B connects to the output transformer at all. I only see it going to the 1st Audio Amplifier and the Phase Inverter.

Curtis Eickerman

In the literature in the first pages for testing voltages from the rectifier it shows the test points . And at test point B it should be 200 v. And the remedies or causes it lists the last one is t200 .i haven't really thought about why. Just sayin that's something but I have replaced all the other causes it lists

Yes but it lists T200 as a cause of high voltage, not low voltage at test point B.

I assumed you checked and have about -65 VDC at the negative end of C103 (and I do mean at the cap itself.).

just checked. Yes I have -64.5 volts there.

well hope nodody will kill me but I got rid of the hum completely . capacitor c 104 a .5uf cap that comes from the rectifier . I was determined to find the problem so I got the schematic blown up and a real nice one someone here gave me . I started to check voltages everywhere it showed it. I didnt get very far the first place I went to look I noticed that one end of c 104 wasnt to a ground. So I looked at the schematic for a half hour to make sure I screwed it up I had soldered the connection one tab over to the left on the drawing by accident . I changed it and eureka its perfect now . Thank you everybody for all your help, without the help I wouldn't have been so determined to fix it . Now I can try to get FM working . AM and SW work great I'll keep you all informed

That makes sense. I noticed earlier that .5 MFD capacitor filters the bias for the 6SQ7, which is unusual since that tube usually uses a grid leak or cathode bias. I didn't mention to check it as you said you changed all the capacitors, while that should have been the clue!
Don

You wouldn't be the first person to solder something to the wrong terminal. If I only had a dollar for every time I...

Curtis Eickerman

I made a quick video for you of the radio playing and starting the next phase

http://m.youtube.com/#/watch?v=0JAi-OF0qdw

ah you didnt ground the ennnnnhhh out of it

Don, you called it, it was missing from the circuit.
Bill J.

Nice work!

If anyone else had trouble with the video link above as I did, I found the video here http://www.youtube.com/watch?v=0JAi-OF0qdw

Curtis Eickerman