Technical information

3. Measure driver and PA tube voltages. The Alignment Manual has tables with the proper
voltages. Make sure the 6146B screen grid 200 VDC regulation has not been molested or has
an open zener.
CB Exorcism
One of my brand new 6146W experienced an internal short (explosion white splat on the side, blown
fuse, open filament etc).
Transmit on CB Channels
This involves adding a jumper on the Driver board band switch and tweaking the Driver tube output coil.
I left the jumper and re-adjusted the Driver tube output coil for 10 meters.
Stupid Attempt at More Power
The PA screen grid has a regulated 200VDC design. Someone had removed the series 5.1k 2 watt and
200 volt zener to ground and added a series 7k resistor. I believe this resulted in blowing my 6146W
since I measured 356 volt swings down to 290 volts when loaded. The max screen grid voltage in the
6146W datasheet is 250 volts!
NTE has a 200 volt 10 watt stud mount zener (NTE5232A) that works well. Earlier models used two five
watt zeners in series.
Sprocket
http://www.dailymotion.com/video/x9p5ey_sprockets-germany-s-most-disturbing_shortfilms
After initial inspection, I was gloating that there were zero cracks on my nylon sprockets and gears –
what a buy, what a buyer. Much had been written about geezer nylon cracks. This soon faded after
performing the calibration procedures – many cracks now plus some slippage even after adding C
rings.
I used the excellent chain and sprocket replacement instructions provided by KX4OM. I recommend
biting the bullet and replace them all. I tried the C rings first but they eventually failed – simply too much
geezer nylon dying. It would also be possible to use ball chains and sprockets vs. the ladder chains.
A crack had also appeared on one of the LO board tuning capacitor gears so I replaced it from a parts
rig.