R-390A Ballast

[W7SOE]

I had to replace the ballast tube in the 390A last night for the second time.  I know this tube has been discussed ad nauseam but now I am paying attention to it as they are $$.

What I am asking is this; is it reasonable to keep the receiver on (everything powered/lit up) just to keep this one tube from heading south?  Maybe only during the winter months?   

Rich

[W7SOE]

Or maybe I should do the 12ba6 conversion I just found.....   

[Edward Cain]

Hi Rich,
   What is the 12BA6 conversion?
   I've done a solid state replacement using a couple of zeners and a resistor. I think I got the info from Electric Radio.

Ed

[W7SOE]

Hi Rich,
   What is the 12BA6 conversion?
   I've done a solid state replacement using a couple of zeners and a resistor. I think I got the info from Electric Radio.

Ed

You replace V505 (The BFO oscillator tube) and V701 (the PTO oscillator tube) with 12BA6 tubes.   Then jumper pins 2 and 7 of the 3TF7 socket.

[WV Hoopie]

I'll second the 12ba6 mod. Jumper pins 2&7 on the ballast tube socket. Replace the PTO & BFO toobs from 6ba6's to 12ba6's.

There is no need for that pricey ballast toob. U are not in the back of a duce & 1/2 towing a generator over hill and dale! Most homes in the US have a stable power supply.

Save ur money and buy good whisky!!!!!!

Craig,

[N2DTS]

I just stuck a resistor in place of the ballast tube shortly after I got my R390a, and it ran for 20 years like that fine....

I don't remember the value, nor did the receiver drift.

Brett

[WU2D]

NOOOOOOOOOOOOOOOOOOOOOO!!!!!

[w3jn]

I think I posted the 12BA6 conversion in the Receivers section of the Handbook forum here, although I claim no originality of the idea 

Done that on every R-390/390A/391 I have, and as Craig said, unless you're running on a generator with poor regulation, you'll never notice the difference.