Wiring, Smoke Test, Alignment
The construction process continued with wiring the underside of the chassis. I acquired NOS lacquered, cloth covered wire in several different gauges. All components (carbon comp. resistors, caps, etc.) are NOS, mostly 50/60s vintage. Wide, waxed covered, white dental floss was used for lacing the wire bundles where needed. In commercial gear with wire harnesses, lacing was generally done first, then the harness installed. For this one-off homebew project, I just laced the wire bundles in-place after installation. Continue reading 1934 Superhet Receiver #9
Front Panel Embellishments
The final touches on the front panel were installed today. Dial markers were added just above the BFO, RF gain, and crystal filter phasing control knobs. The markers were made by filing down the heads of #2-56 screws. These are similar to the dial markers used on the National HRO series receivers.
Next, an information tag and main tuning calibration chart were added. The hi-resolution (300dpi) graphics were created in GIMP (GNU Image Manipulation Program). The calibration charts (160, 80, 40, 20) were modelled after the early HRO style paper charts that were on the plugin coilsets, with a 0.1 in. grid. In fact, the satin-black metal frames and clear plastic covers (yellowed from age) to mount the information tag and calibration chart were taken from an old HRO coilset. The frames are held in place with #4-40 black screws. The front panel has tapped holes to accept the screws. When changing bands, the calibration chart above the main tuning dial can be changed by removing the top screws and loosening the bottom screws. The charts can be slide in and out from the top.
The yellowing of the plastic covers really adds a nostalgic appearance to the receiver.
With all of the front panel work complete, it’s time to start wiring!
Power Cable, Cabinet, Front Panel…
I was able to procure a vintage brown cloth covered, 6-conductor power cable. Two(2) of the conductors are #14, adequate for the filament current if I decide to use 2.5V tubes (approx 11A including dial lamps). Only two of the smaller gauge conductors will be used for B+ and B- (ground). The cable is fed through a hole with rubber grommet in the rear and held in place with a metal cable clamp inside the chassis. Continue reading 1934 Superhet Receiver #7