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Rebuilding my 1966 Novice station
My Novice station (WN8VVJ) back in 1966 consisted of a BC-312N receiver with a home brew AC power supply, a Knight T-60 transmitter with a few 40-meter FT-243 crystals, and a 40-meter dipole. I recently decided to rebuild my Novice station so I set out to find a good BC-312N and a T-60. I found them on eBay and now I’m working on getting the BC-312N receiver to work. There have been some wiring changes made by a previous owner(s), especially at the front panel interconnecting SO-1 socket which has been removed. Both units will require work to return to full operational status. The BC-312N home-built power supply will consist of a Heathkit Apache TX-1 LV B+ transformer that has 600VAC CT at 170ma HV winding, 2 x 5VAC, and 2 x 6.3VAC filament windings.
BC-312N after front panel clean up front view. The paint-scraped dial lamp enclosure was replaced with one from a spare BC-312M. The front panel was scrubbed with a toothbrush and Armor All to remove the dust and dirt.
The phone socket cover springs were cleaned and applied a small amount of lubricant.
The hole left by removing the SO-1 interconnecting socket was plugged with a metal plug and then painted Satin Black.
The missing spare fuse holer was replaced with a new spare fuse holder.
The dial lamps have been tested (2 x #47 in series) along with the dial lamp dimmer control, and they all work.
I’ve run a series of tests on the B+ bus using my PS-3 HV-regulated power supply. The test consisted of removing all 9 tubes and applying B+ to tab 7 and ground return to tab 8 on the 9-tab terminal strip. The B+ bus testing had a problem with the current rising on its own at 4 DC voltage levels, 100, 150, 200, and 250VDC. Disconnecting, checking, and reconnecting can capacitors C29, C30, and C31 lead appear to have fixed the current increasing problem, why I can only guess there may have been a short in the wiring to one or all 3 of the can capacitors. Further B+ tests were conducted at voltage levels starting at 100VDC, increasing to 150VDC, 200VDC, and ending at 250VDC. Currents at those 4 voltage levels remain stable.
Dial lamp tests were conducted using a 12VDC 5 amp switching supply connected to tab 9 and ground return on tab 8. Filament testing was successful. An Ohm meter test for shorts was conducted by removing all tubes and then measuring tabs 2 and 6. The rest result was infinity which is what it’s supposed to be. An additional filament test was conducted by inserting all tubes in their sockets and applying 12VDC to tabs 2 and 6 (tube filaments are wired in series/parallel). Tests were successful with 12VDC and a current of 1.7 amps. All tubes were checked for shorts and open filaments, but none were found. Tests were also performed for simple conduction in the tube. All tubes passed.
Testing of T1 and T2 audio transformers had good test results.
Resistance measurements were performed. There were some resistance measurements that were out of tolerance but others were within tolerance.
No shorts were found and the B+ tab 7 resistance measurement was found to be 16.7K, exactly what was listed in the TM 11-4001 technical manual.
More tests are needed before applying full filament and B+ voltages.
BC-312N top front view (cabinet repainted). The cabinet was stripped of its paint (too many chips and scraps) using Citristrip paint remover. The cabinet was cleaned then sanded to remove any/all rough spots then painted 2 coats of Satin Black.
Knight T-60 front view before full restoration. Restoration work on the T-60 will commence once the BC-312N receiver has been repaired and is in normal operational condition.
Knightkit T60 front view before restoration
