[Jayce]

I have been trying to disassemble the Zenith 12H090Z I bought a couple weeks back and have hit a snag. The knobs have taken a real set on the shafts and I am pratically dragging the whole console around pulling on them! I see no set screws and the cabinet design makes for lousy leverage. Any hints on how to get them off without (further) damage to the wood or chassis?
I also now remember why I have never tried to take apart a postwar Zenith before. Lots of plugs and screws!

[morzh]

Have you tried any penetrating lubes such as Liquid Wrench?

Of course you have to be able to get the stuff from behind so I am not sure what your situation is, but you still might using that thin plastic straw get the lube in.

Some heating/cooling cycling might work but one should be careful so not to damage the knobs.

Have you tried light tapping around a knob?

[Jamie]

Wrap a shoestring around the shaft, behind the knob. Pull each end out at 3 and 9 o'clock positions, then pull on the strings while pressing down on the cabinet with your thumbs. The knob will go flying, so beware. Sometimes penetrating oil helps.

[klondike98]

Jayce, here's a string I started on stuck knobs. Mine had a touch of glue in it as well
http://philcoradio.com/phorum/showthread.php?tid=7454

The penetrating oil/WD-40 with a little heating the shaft with the soldering gun finally worked on mine.

[Jayce]

Thanks for the advice. I'll have to try and get some WD-40 as I am fresh out of it. The chassis slope upwards in this style Zenith and it is not easy to get anything up into the knob shafts. Now, I wonder if I have a shoelace strong enough to wrap around the shaft of the knob? Also, something tells me I should keep my mouth closed and get a pair of safety glasses on when I try this!

[klondike98]

keep my mouth closed and get a pair of safety glasses on when I try this!

[morzh]

<<<The knob will go flying...keep my mouth closed and get a pair of safety glasses on >>>

Also make sure the knob is above the waist level and just in case wear the cup.

[Jayce]

Hmm, good advice!

[Arran]

Yes, if you can get some sort of penetrating oil onto the control shafts behind the knobs that would help, but let it sit for a few hours after you do.
If the chassis is leaning backwards tilt the console forward a bit when you spray it in there, maybe put some books under the backs of the feet.
Wrapping a rag or a string around the back of the knobs helps with leverage, sometimes you can keep winding it around until the pressure pulls the knobs off.
Regards
Arran

[tom.seeger]

I had a stubborn one recently. After trying all sorts of prying etc. I tried some gentle warming with a heat gun. I shielded the front panel with tin foil and scrap metal, to not damage the finish. Once the knob got quite hot, it popped right off. Someone had glued it with what looked like carpenters glue. This process did not damage to the Bakelite knob.