Missing parts are easy to find on eBay, so replacing the antenna was easy, except I had to paint the plastic tip on the end brown to match the radio, since the only ones available had black tips. I recapped the original 6T41Z chassis, but could never get it to play reliably; audio would fade away after a few minutes and the receiver had no sensitivity at all. All of these issues could be tracked down and repaired, but when a very rare, nice 6A41 chassis showed up on eBay with a pristine dial face, I grabbed it.
After a recap, the 6A41 played very well, with good audio and great sensitivity, as a Trans-Oceanic should. The 6A40 chassis was the final chassis used in the tube Trans-Oceanics, and the 6A41 chassis is identical, except it has a brown dial face to match the leather covering.
After gently cleaning the leather covering with alcohol and 0000 steel wool, the leather was a shade lighter. I then used brown Kiwi Scuff-Kote to restain the leather. This darkened the scrapes and scratches in the leather, which looked better than the raw exposed leather. Then I polished the leather with brown shoe polish, which improved the looks quite a bit. Normally I would remove the brass hardware, strip it in white vinegar, and re-lacquer it. I did not do that with this radio as I felt it would look weird to have shiny brass with a well worn cabinet. I cleaned the brass, but otherwise left it as it was. The radio presents as a survivor that's got a few miles on it.
While I had the chassis out for service, I decided to convert the dial light from an incandescent bulb to LED so I could leave it on while using the radio. The dial light circuit in the 600 series Transoceanics was originally powered by a 1.5 Z-1 battery, and a momentary slide switch on the front was held in the on position while tuning the radio in dim light.
First, I mounted a 3 volt warm white LED in a screw base to fit the OEM lamp holder (see photo, bottom center). To power the LED, I wired a two prong connector to a 2x1 C cell holder, which provides 3 volts to power the LED. The only modification I had to make to the dial light circuit was to remove the spring from the momentary slide switch so that the LED could be switched on and off normally.
The single LED works very well in place of the original incandescent bulb. The photo, at right, isn't very good, but the light is much more even than it appears in the photo. The light is off in the last photo.