View Full Version : RCA CTC-4 back cover reproduction


ChrisW6ATV
12-20-2015, 11:15 PM
Hi-

Last year, I picked up a CTC-4 that was missing its back cover (and had a broken CRT neck), and I just recently decided to make a replacement back for it, before installing a replacement CRT. Bob (ohohyodafarted here on Videokarma) had one made for his Hallicrafters CTC-4 "clone" set as described here, at a CNC shop:

http://antiquetvguy.com/WebPages/TheRestorations/1955Hallicrafters21CK801M/1955-Hallicrafters-21CK801M.html

A professional reproduction like that is out of my budget at the moment, but with hardboard panels available for $8 that are big enough for four backs, I figured I would try making my own, and in the process get all of the measurements needed to get quotes from local CNC shops or owners myself. I made my measurements from a combination of my own CTC-4, Bob's pictures, and Phil Nelson's pictures on his site:

http://antiqueradio.org/RCACTC-4ColorTelevision.htm

Below is a picture of the result; it is not perfect, but good enough to use until I get a machine-cut one made. More details are available here:

http://70.36.238.5/ctc4back/

Regarding commercial fabrication by a CNC shop, I remember reading of at least one other CTC-4 owner needing a back, so maybe I should find out if several can be made at a cost savings compared to just one or two. The one change I made from my measurements (which are only educated guesses, without access to an original) is to increase the height of the back panel from 23-3/4" to 24 inches, because my set's bottom-edge screw holes were made into the edge of the plywood platform that holds the chassis, and they are not very secure as shown in the other picture below. Adding a quarter-inch allows the screws to be put into the solid wood strip on the bottom edge as they are on the top edge.

I would appreciate any comments on this work, or my plans to get cost quotes. Once I transfer my hand-made measurements to some electronic form (whether just a graphic image or a CAD file of some sort), I will be happy to share them with others here.

hi_volt
12-21-2015, 08:29 AM
Damn....that looks really good! I have a CTC-5 Chandler that is also missing the back cover. Great inspiration for me to do one myself

Steve D.
12-21-2015, 11:13 AM
Super job Chris.
Some years ago I had a request from the new owner of a backless RCA CTC-5 Wingate to supply measurements from my CTC-5 back cover on my Wingate model as well as supply photos for him. I thought sending measurements would not be error free. So I removed my set's back and traced it on a large piece of butcher paper. This included all cut outs, retaining screw holes and about 20 of the vent holes. I the rolled up the paper and slipped it into a tube mailer along w/the photos and sent it along. This proved to be far more accurate than measurements alone. I also added measurements for the bump-out. Just an alternate method for a template.

-Steve D.

ChrisW6ATV
12-21-2015, 07:49 PM
Thanks for the nice comments, hi_volt and Steve.

I also have a CTC-5, with its back, and I confirmed or chose some of my measurements from it (such as the hole pattern spacing, which matches the CTC-4). It is interesting that the CTC-5 CRT box is a tall rectangle versus the square one on the CTC-4s. Some versions of the '5 must have their CRTs in a different position relative to the chassis and back, I can only guess.

ohohyodafarted
12-22-2015, 08:14 PM
Fine Job Chris! Looks as good as the ones I paid big bucks to have CNC'd.

YOu might want to try using the styrene plastic modeling sheets for making the bumpout like I made. IN hard plastic, they are a lot more durable than the cheesy cardboard that RCA used. Easily painted with spray paint to approximate the dark chocolate color of the RCA bump out.

Very nice job Chris!

ChrisW6ATV
12-23-2015, 02:09 AM
Thanks, Bob. I do like how your CRT box came out; I will look for that material here.