[Steve Davis]

I removed the tuning condenser, the choke and the driver transformer. I unbolted the power transformer but did not disconnect the wiring. This allowed the transformer to be moved enough to clean around and under. I then used lacquer thinner and a small, toothbrush size wire brush to scrub the chassis. It didn't turn out as well as I had hoped but it doesn't seem to get better with more rubbing so it will have to do.

[morzh]

I thought wire brush would scratch worse than pumice, no?

[GarySP]

Really depends on the stiffness of the brush being used. I have brass toothbrush-sized brushes that won't scratch unless the user is too aggressively applying pressure. Take care and BE HEALTHY! Gary

[Ron Ramirez]

I think it looks much better, Steve.

[RodB]

+1 on the brass brush, Gary. The chassis I'm working on now is the same way. I don't know what causes the plating to stain like that but it will have to stay. The AK chassis I just finished was a snap to clean and what a show. Almost like new after 90 years.

[Chas]

Take this as advice from experience...

As "our" radios age, the chassis metals, the bits that are riveted, screwed and soldered together develop corrosion between dissimilar metals. Even if not visible and even if a DC meter "seems" to indicate the joint is O.K. RF does not like a joint with such corrosion. There is steel, brass, nickleplate, cadmium & zinc all crushed together in, well, an unhappy marriage.

When a chassis is in some state of disassembly, take the time to re-solder chassis soldered joints and riveted electrical joints, this can be tough unless a larger iron is used but chassis heating with a heat gun helps. If a riveted electrical joint can't be soldered, drill out and used hardware with serrated washers.

GL

Chas

[Steve Davis]

I removed the end bells from the power transformer and painted them along with the choke and driver transformer that I had previously removed. I then masked the coil of the power transformer and slipped heavy paper under core to mask the chassis, I then painted the transformer core.

[Ron Ramirez]

[morzh]

New old stock chassis in making

[radiorich]

Hello Steve,
That looks great so far I have Zenith model 715 that really needs it's poor chassis redone .


Sincerely Richard

[Steve Davis]

Now I'm going to re-stuff the filter capacitors using dipped film capacitors.

     
As with the rest of the chassis, the filter caps have a thick layer of tobacco tar.

   
While turning the caps in the lathe, I used 0000 steel wool soaked in lacquer thinner to clean and polish the cans.

   
I used the lathe to make nice smooth cuts to remove the bottom ends of the cans. One cap is a dual  the other is a single.
The single will be used as the second filter and is made up of two 4.7uf and two 2.2uf film capacitors. Hot glue is used the hold the film capacitors in a stack. The dual uses two 4.7uf and a 2.2uf film capacitors for the bias filter and two 3.3uf and a 2.2uf for the first filter.

   
Heat shrink tubing is used to keep the leads from touching the can.

   
The filter capacitors are ready to re-install.

Steve

[morzh]

Nice looking.

I always make sure only straight parts of the wires touch the heatshrink from inside, and not the solder joints, which have tendency to rub through, unless made exceptionally smooth without wires soldered ends looking sideways a bit.
If in doubt, I use double-heatshrink.

[Steve Davis]

Mike, I did add a dab of hot glue over the solder joints before the heat shrink, I don't think there is any chance of the connections rubbing through.

[Steve Davis]

On to the four section electrolytic. This cap is mounted horizontally under the chassis using a clamp on the end opposite the terminals.

   
Using the lathe to make a nice clean cut near the clamped end of capacitor. 

   
On this one, I'm using a piece of 1-1/2 PVC conduit as a sleeve to hold the can together. I'm using three 1uf and one 2.2uf film capacitors.

   
Four holes were drilled in end of the capacitor can, one near each terminal to bring out one lead from each capacitor. The negative common lead will be brought out at the other end of the can.

   
The leads are connected to each of the terminals. The common lead near the bottom will be under the mounting clamp to provide the ground connection.

[MrFixr55]

Seriously nice work!! Ready for another 90 years!!