Zenith 6D2614
 

I recently purchased a Zenith table radio, model 6D2614, chassis 5B01/6B01. This was my first successful electronic restoration, and now I have just a few questions. It appears that it is not a hot chassis radio, because the line cord is not directly connected to the chassis like some of the other radios I have. Can anyone verify this? Also just a general question- I have read that to test the audio section of a radio, you can connect an audio source to the volume controls wiper. Is this applicable to any radio? Where should the sources ground be connected? I will post the schematic when I find it and pictures if needed.

Two slightly different versions:
http://oldtech.net/Zenith/VolumeII/Page184.gif
http://www.nostalgiaair.org/PagesByM...8/M0025068.pdf

Technically I'd call yours a hot chassis set.
If there is not a power transformer in a set it becomes a hot chassis in my book. Some hot chassis were "hotter" than others. The worst have direct conections between the power cord and the chassis, and the less dangerous but still somewhat unsafe ones had an indirect connection to ground through a resistor and or a capacitor.

I'd hook up the external audio input source to the junction of R6 and R7 and the ground of the audio source to the junction of R7 and R8(going by the part numbers in the first link). This should allow you to use the sets origional volume control, but for safety sakes I reccomend either using an audio source that does not plug into the wall, or powering the Zenith through an isolation transformer.

Hope this helps.

I would make two comments. First, disconnect the audio from the detector so you don't hear both the external source and the radio at once. Second, if you 'isolate' the chassis from the ground of the external source with a small capacitor it may work okay and be safer. You may have to reverse the plug in the wall to reduce hum. And of course also isolate the hot lead.

So a small cap (is a .01mfd ok?) on both the hot and ground of the audio source? Would tuning clear spot on the dial work the same as disconnecting the detector? I have also read about AC rated caps, where would these be placed?

OOPs. Failed to read previous poster's suggestion of isolation transformer. :o