Late 1920s Eveready Model 1 TRF Set need info

[vortalexfan]

Originally Posted by Electronic M

With the rectifier out there's no B+ to measure. There is the high voltage winding on the power transformer that supplies AC to the rectifier that you could measure by sticking your DMM leads in the skinny pin holes on the 80 rectifier socket and fishing around for the contacts.

High Voltage is working as it should it seems. I measured the plate voltage for the 80 Rectifier Tube socket (the small pins) as you suggested and there was a little over 400V AC on the plates of the Rectifier Tube socket which sounds about right.

[vortalexfan]

OK so I checked the B+ voltage with the rectifier tube in (just the rectifier tube in) and I got around 320V DC and with the 2 71A output tubes in it dropped to 160V DC so I think the B+ voltage is working as it should, which I think the voltage will drop down to around the 90V DC ballpark range specified on the schematic once the tuner section is hooked back into the circuit (that will add the rest of the 5 tubes in the radio into the circuit).

So it seems like besides having to install the modern plate resistor into the circuit in place of the old fuse style one (by soldering it onto the connector leads under the chassis for the plate resistor socket above) I think this radio will be ready to go once I get the replacement speaker in.

[vortalexfan]

OK so an update:

I installed the 47K Ohm resistor for the plate resistor, and hooked the tuner portion of the radio up to the power supply and installed the tubes and powered it on and monitored the B+ voltage and it was nearly spot on at around 89.7 VDC, so it looks like everything is working as it should!

Now all I need to do is wait for the replacement speaker to come so I can repair the speaker for this thing and so I can test the radio out and see if it can pick any stations up!