Quote:
Originally Posted by Reece
Note that the cathodes of the diodes don't go to chassis ground (which would represent a dead short!) They go to the field coil and the + end of the first filter cap.
As to the 6X5 heater, yes, it can be left connected for show, but disconnecting it would give the sometimes feverish Zenith power xfrmr a bit of a break!
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Thanks for correcting me on this Reece. I really don't know what propelled me to say that except to say that I had been working on an old Zenith "roundie" color tv that I have and I have been watching cathode current on the horizontal output tube. To do that I break the grounded cathode to place an ammeter in series. No excuse really for mixing that up with a rectifier in a power supply. Geez!
Anyway, I have a couple of 6X5GT tubes that I can use for the time being under close watch in these early stages of resurrection. Swizzyman gave a great read on these bad rep tubes. I hope Captain Clock read his post and I can attest to the GTs shorting as the tube that came in this Zenith was a GT with low emissions. I scavenged a couple of other GTs that I had sitting in boxes and threw them in my trusty old Sylvania 140 tester. One was fine and is in the now playing radio. The other gave a sharp flash when I plugged it in and the neon short lamp went full on. Good thing to have a few old tube testers around!
So yes folks this old Zenith radio came to life last night with little more than a dusting out, a rectifier tube and pin cleaning on only a few of the other tubes. The story's not over though. The volume is pretty low; the tuning eye looks completely dead, and all of that neat O Zenith tuning presets or whatnot has to be cleaned and lubed. I'm assuming that they are station presets. The closest thing I have seen to what I see there is in my Transoceanic radios and they are band switches.