[morzh]

Hey guys, I am back to the project, finally.

Need to clean the whole thing.
I started with cleaning the tuning cap.
It is a three-section one.

Really filthy.
What is a good way to clean it? So not to damage insulation, give it some shine, and (I think it is needed) to lube the rubbing places?

[37silverstreak]

Hi, I cleaned the tuning caps on two of my 70's by removing them from the chassis ( I had to replace the rubber mounts anyway) and then removed the rotors from the stator frame. I soaked the parts in a solution of "Extreme Green" parts cleaner and hot water. I left them to soak overnight then rinsed with hot water and used a blow dryer to thoroughly dry them. I used a wire wheel and dremel tool to buff the parts, then reassemble. they both turned out great! As for lubing, you can use a little conductive grease or vaseline for areas where you don't need to maintain electrical conductance.

[Arran]

Hey guys, I am back to the project, finally.

Need to clean the whole thing.
I started with cleaning the tuning cap.
It is a three-section one.

Really filthy.
What is a good way to clean it? So not to damage insulation, give it some shine, and (I think it is needed) to lube the rubbing places?

I would not take the rotor out of the tuning cap except as a last resort regardless of what anyone suggests, you may get it apart but you will have all kinds of troble getting the rotor and stator lined up again. You can remover the entire tuning capacitor and wash it, I like to use TSP and hot water but strong soap will do it, then rinse it out, then let it dry with the plates open, then regrease or oil the bearings.
Regards
Arran

[Texasrocker]

If the rubber mounting grommets are still good, this is a simple fix leaving the tuning cap on the chassis. Use compressed air to blow out all the old dust and debris you can. Place some clean paper towels below the tuning cap. Flood the entire tuning condenser with "Blue Shower" electronics cleaner with tuner fully opened. Repeat a couple shots of the cleaner. Blue Shower cleans and dries fast. Your Done! All debris removed! If the rubber grommets under the tuning cap need replacing to tighten to chassis again, find similar size small rubber faucet washers , drill out the center holes, and fit them both on top & under chassis. The faucet washers can be found in the plumbing departments of Lowes, Home Depot, and hardware stores. Reinstall the new grommets to acheive proper mounting height, and positioning, as required to the cabinet. Blue Shower Electronics cleaners in the spray cans can be found online, or at local electronics wholesalers type stores.

[Radioroslyn]

By the by on the 20 the rotor comes out easily and isn't a problem to align. But it is made of steel plates and a brass shaft. Not aluminum like more modern sets.Also it doesn't have avc so if I remember correctly the tuning condenser bolts right to the chassis with no rubber parts. Most I've seen get a bit rusty over the last 80+ yrs
Terry

[morzh]

Hi guys,

Thanks for the replies.

There are no rubber grommets. The cap's rotor is electrically connected to the housing and through it to the Chassis GND.

For short, before I got all these replies I took the cap apart (easy), and washed it in the dishwasher. I had some reservations, but it came out good. I decided not to buff anything: I need it clean (it is now), but not necessarily glittering.

The cap is easily and logically disassembles and re-assembles; it's a snap to both take the rotor out and to put it back, so no scare here. The two steel springs that control the rotor's location are unique and fit only one way, so no problem with remembering which one's where.

To take the cap out is 5 wires (3 wires to the stator and 2 to the light bulb) and 4 screws - three hex screws and the one long screw holding the scale mechanism.

Now I need to buy one 71A tube (one out of two has no filament continuity) and connect Hammond Xformer to the speaker.

Wish me luck

[Arran]

Hi guys,

Thanks for the replies.

There are no rubber grommets. The cap's rotor is electrically connected to the housing and through it to the Chassis GND.

For short, before I got all these replies I took the cap apart (easy), and washed it in the dishwasher. I had some reservations, but it came out good. I decided not to buff anything: I need it clean (it is now), but not necessarily glittering.

The cap is easily and logically disassembles and re-assembles; it's a snap to both take the rotor out and to put it back, so no scare here. The two steel springs that control the rotor's location are unique and fit only one way, so no problem with remembering which one's where.

To take the cap out is 5 wires (3 wires to the stator and 2 to the light bulb) and 4 screws - three hex screws and the one long screw holding the scale mechanism.

Now I need to buy one 71A tube (one out of two has no filament continuity) and connect Hammond Xformer to the speaker.

Wish me luck

Before you spring for a new 71A try resoldering the filament pins, some of those older tubes have bad solder joints by now.
Regards
Arran

[morzh]

Before you spring for a new 71A try resoldering the filament pins, some of those older tubes have bad solder joints by now.
Regards
Arran

Thanks, Arran.

(I actually bought a pair - not too expensive and the guy claimed he tested them on Hikock; he specializes in tubes and his feedback was 100% so I trust him).

I looked inside the tube - the filament's gone (the two tensioners are up in the air - they should be sunk inside, holding the filaments), so it is not really fixable.

But, hey - thanks, it never occurred to me this could actually happen, so in the future I'll keep that in mind and will be checking it.

Mike.