Painting the transformer cover and plate chokes

[sbelyo]

I seem to remember reading that the screw heads for the power transformer must make contact with the bare metal after painting.  Am I correct?

Also If I paint the plate choke frames, do those screw heads have to make contact with the bare metal of the plate choke frame as well?

 

[Paul Birkeland]

Yes, though if you tighten the screws down nice and hard, you'll likely make contact adequately.

-PB

 

[wink]

Would someone mind elaborating a little more on this please? I am currently putting together a few kits and a lot of my parts were powder coated (the top plate and any other metal that is on top of the amp). Anything on the bottom was left alone. I also have my screw heads painted. What parts would I have to alter to make this work? thanks

 

[mcandmar]

Transformer bell, and Choke housings need to have an electrical contact to the screws.  One of the screws for each (rear most on chokes, and rear right on main transformer) are joined together on the under side by a wire to earth.  Its for safety, and also to minimize any hum being picked up.

Any terminal standoffs that have connections on the middle post need to have a good electrical contact to the chassis plate as they are also part of the earthing circuit.

 

[wink]

All of the terminals and the ground tabs have been ground down to bare metal before I started. I wasn't aware of the bell, choke housing, and screws. Im going to have to figure this out now. I'm glad I'm not too far along in the build. Thanks for the info, much appreciated.

 

[2wo]

You can always place a sharp star washer to cut through the paint, if you think you need it...John 

 

[wink]

Unfortunately it's powder coat. It's a little harder of a finish than paint but I will give it a try. Thanks for the reply