I noticed that my tone controls dont work on my Zenith 8s463. When I select one on the tone buttons the radio hums bad. Also then I touch any of the wires going to the controls it hums really loud.

Could be broken wires. Could be open condensers. Could be shorted condensers. It is wise to check all condensers and resistors in the tone filtering network. Make sure that condensers have absolutely no leakage what-so-ever. It is necessary to remove a condenser in order to test it properly with your multi-meter. For values over .001 MFD, the needle will visibly jump up and then fall back down, even if only slightly. It must fall back to exactly where it started. If it falls further when the leads are removed from the condenser, then the condenser has unacceptable leakage. Most radio repairmen simply replace all of the old condensers instead of testing them. However, for your technical knowledge it is important to know just how precise things must be when it comes to condensers. If a condenser is causing hum, however, it probably has rather significant leakage. Never-the-less, make sure that all condensers are in top working order. Miniscual leakage can dramatically affect grid biasing, etc.

Thomas

Thomas, I replaced all of the caps and wiring. There is a faint hum all the time but when you touch the wires or activate the switches the hum is extremely loud.

Perhaps you miswired something.

A lot of radios hum faintly, though, depending on the type of hum, it could be power supply hum (somewhat normal) or hum due to poor shielding in the audio section.

You must follow the schematic perfectly. Make sure that everything is wired exactly the same way as in the schematic (electrically, not physically). Maybe, too, a wire is broken. If you hooked something to a filament lead instead of the chassis, this would make things hum loudly. Lots of possibilities.

Thomas

Thomas, are the Zenith tone switches you have seen naturally all open or are they naturally all closed?

Some are open and some are closed. Depends on the circuit and the radio. I don't currently own a Zenith with these switches, but I do recall that some closed and some opened when you pulled them all out. One switch in particular, I believe the Normal switch, connects a small value condenser from the plate of the 1st AF tube to B-. If the condenser shorts here or is misconnected, it can kill the audio signal and cause a lot of hum. All of the other tone controls can cause hum and kill the audio, too, but different things must occur for this to happen.

Again, go through everything and make sure that you connected all of the new components and wires properly.

Thomas

One interesting thing I did in a Zenith I fixed for someone is reverse the Speech and Treble wires. I found that the speech button was increasing the very high crisp treble, while the treble button was increasing the sharp lower treble. Typically this range is increased for speech. When I reversed the wires, the speech button increased the sharp treble, and the treble button increased the very high treble, where all of the light and airy sounds occur.

Not all circuits are the same, and so not all radios can be altered in this way. Some radios actually use the speaker's wiring in some of the switches. I had a chassis from a 1951 consol that put a choke in series with the speaker's voice coil for one of the settings. I forgot which it was.

Thomas

Randy, make sure the insulation on the wires coming from the radio to the switch are not shorting, these are rubber coated and will crumble and cause the symtoms you have ,especily with the way the wires are clumped together, my zenith did the same thing I had to replace all the wires and now my tone controls work the way they should.
E.

:I noticed that my tone controls dont work on my Zenith 8s463. When I select one on the tone buttons the radio hums bad. Also then I touch any of the wires going to the controls it hums really loud.

Elton, how do your buttons work? Are they all in and then you pull one out or are they all out and you push one in????

Randy is all matter of preference, my 10S464 I started out with all my buttons out, but now I find it sounds better with all in and pulling out the option I want bass, lo bass, voice, etc.
E.
:Elton, how do your buttons work? Are they all in and then you pull one out or are they all out and you push one in????

All of the buttons, except for the Normal button, enhance the audio when they are pulled out in all of the radios which I have operated. Depending on when the radio was manufactured and the design of any particular radio's tone circuit, switches may be closed or opened when the levers are pulled out. For instance, in radios where a choke was used in series with the speaker, most likely for treble, pulling the switch out would enhance the audio, and would short out the choke, bypassing it. In radios where a resistor limited bass (a resistor will do this if placed across an audio source....it tightens up the circuit and makes the condensers less responsive to bass), pulling out the bass lever would actually disconnect such a resistor. In some radios bass would be limited by a smaller value condenser, and the bass switch would then close when pulled out, shorting across the condenser.

The normal switch in most cases connects a condenser to the plate of the 1st audio tube. It does this when pulled out, and makes the audio very plain.

As Elton said, you can push in or pull out whatever levers you want. It's all up to your taste. I found that the best sound was obtained when the Normal and Speech buttons were left in, and the rest were pulled out. In radios where the Treble button enhances harsh highs (speech), and the Speech button enhances the highest register, then it sounds best with the Speech out and the Treble in.

Thomas