Hallicrafters 505 Soon to hit the Bench

[jr_tech]

Well, the Hallicrafters has made it to the bench and most capacitors have been replaced.



I noticed a serious error in the Sams 91-6 folder... the polarities of c-4 a & b are backwards... negative ground is indicated but both of thes caps must be wired with positive ground, for the circuit to make sense.

I have re-capped the HV supply and have it operating on the bench (most of the time).



Most of the time it is well behaved, delivering around 4.2 kV with 220 volts input, drawing about 13 mA, but once in a while the HV drops to zero and the current drawn by the poor little 6c4 shoots up to more than 60mA! This does note bode well, I suspect an intermittent shorted turn in the HV coil.

I may have to get serious about finding a replacment for the HV supply in these electrostatic sets, as I also have the typical slumping HV problem in my Philco 7 incher.

So far, a fun project... I may try fabricate the CRT boot from hobby plastic, if one does not turn up.

jr