Dec 312011
 

I bought a T-368C HF transmitter project back in October, 2007 for $1575.42, and finally started seriously working on it a couple months or so ago. This evening, it got its first taste of power in many years! It’s semi-alive, but needs more work:

  • No actual smoke seen; just a healthy (?) amount of “hot dusty stuff” smell.
  • I can’t seem to get the PA to load up at 150mA in tuning mode as the manual directs; tuning for max RF output gives me about 100mA plate current and 65-70 watts of RF.
  • Full power mode is no-go: I hear some arcing sounds, then the overload relay trips.
  • Both blowers work, though the PA blower is quiet enough that I can’t hear it over the cabinet blower.
  • PA grid drive reads a bit high at 15mA.
  • Int. amp plate current reads 25mA.
  • In AM, I can only get the modulator bias current up to around 40mA. I don’t trust the bias potentiometer based on DMM testing earlier today. Whistling into the mac doesn’t swing the meter higher.
  • The filament voltage meter is a bit sticky; I need to thump on it to see small changes in voltage.
  • I don’t like having the back cover interlock defeated during testing, but those big tubes sure are pretty when they’re all lit up!
┬áHere’s a front view of the transmitter, taken back in 2007 when it was stowed in one of my sea containers:
T-368C Transmitter
This beautiful beast weighs about 750 pounds, so it’s not easy to move around! The three big drawers come out, but each one is pretty heavy. The bottom one is the heaviest, because it has the big power transformers in it. When I unloaded it from the sea container last August and loaded it into my house, I used my Bobcat to move each of the pieces and lift them up my front steps:

It’ll take more work before I’m running my T-368C on the air, but it’s great to see some good signs of life from it!

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