[ARC5] BC-348-R Update

[Ben Hall]

On 8/19/2022 12:39 PM, Doran Platt wrote:
> Yes, Pins 2 and 6 are the "relay" pins that disconnect screen voltage
> from several tubes for muting.  These pins are to be normally closed,
> open on mute. K3HVG

Years ago when I was working on one the BC-348's I've got I did exactly that - forgot about those pins and went somewhat crazy trying to figure out what was going on as it wasn't working.  Finally ended up asking here and was reminded about those pins.  Jumper installed and all was well.  :)

In other news, I think I've got the SLR-M finished.  I've changed the pilot light bias regulation scheme replaced with an LED and zener diode.  25Z6 bias very happy now at -9 or so volts.  All easily removable.  The dropping resistor for the LED is inside the LED's 3D printed housing, and the zener is tacked on top of the turret board.

Next up is a military Super-Pro.  The more I look at it, the more not-so-well-done repairs I find have been done to it.  IE: The original capacitors across the main tuning capacitor sections have been replaced rather sloppily.  The originals were probably silver mica, and silver micas were used in the replacement.  They got the values right - 600 pF - so the theory that they were trying to move tuning around is out the window.

thanks much,
ben