Saturday, September 8, 2018

Teletype and Sherman Tank progress


Ken and I completed the wiring of all AC and DC power on the table. During that process, we checked all the lines for correct connections and absence of short circuits. We did discover two shorts. One was caused by frayed wiring connected to a receptacle, and the other came from wire whiskers  bridging between adjacent terminal on the Transmitter/Distributor connector block. 

The desk has two power switches on the front. One controls the motor on the Transmitter/Distributor and the other controls the REC-30 Power Supply. I checked their operation and found a fault in the Power Supply switching. We discovered that the switch itself was stuck open. It was a double pole, single throw 20A switch which had been wired in parallel to support more than 20A load. 

We picked up a suitable DPST 20A switch from a local hardware store and installed it, restoring the ability to switch the main power supply on and off. 

I began to wire the signal lines, supporting twin lines, a mix of Reperforator, Transmitter/Distributor and Printer/Keyboard plus test plugs. The last set of connections to make come from the complex line switch that supports connecting the reperforator to either of two lines or leave it offline. There are also connections from a Tape Out button that provides idle characters as filler to provide some leader or trailer on a tape being punched. 

We all worked to install the base and connector block into which the model 14 Transmitter/Distributor will slide. This was finished and all the wiring completed, thus we can use the TD as soon as the signal wiring of the desk is complete. 

Marc spent some time putting together the cover for the model 15 printer that will sit atop the desk. There were several doors and flaps that were twisted and fitted badly. Marc spent the time bending these until the closed and opened properly.


Mike did a teardown of the selector mechanism in the reperforator, both to improve its operation and to support some video demonstration of the way that teletype selectors work. 

Mike and Marc designed and installed a modification providing a terminal strip for connections to the reperforator, which provides a neater and more reliable alternative to the directly soldered wiring of the original mechanism. 

Mike did quite a bit of oiling and exercising of all the moving parts. It is largely done now, with most levers or other parts moving easily and promptly. 


Marc's Transmitter/Distributor was assembled and all wiring completed. He did a sequence of adjustments until it performed perfectly. He demonstrated this with a tape he had produced on his keyboard perforator, transmitted flawlessly to his model 15 printers. 

I picked up new brushes to install on my Transmitter Distributor, but for the time being I am waiting until we can manufacture or find a motor pinion supporting the standard 60 wpm transmission speed. 


Nancy selected the tank body color and did a test painting. We are ready to prime and paint all the panels of the tank now. We are still struggling to find right material for tank treads and wheels. 

I spent Saturday building out the front half of the upper body and doing some finishing of the center 'bar' section. We have a few more plywood panels to install but the majority of the front half of the tank is done. I expect to wrap this up on Sunday and to begin building the rear half of the upper body and the rest of the bottom panels. 

Most of front upper body is done, but some panels left to do

Bartenders side view of the front of the tank (sans Turrent on top)

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