Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12) x

Thread Closed
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Philco Model 20 volume control operation
#4

The volume control should be a dual pot. One section, as Keith described pads down the antenna input and decreases the signal level. The second section adjusts the bias on the RF amplifier tubes and sets the level of signal amplification.

It sounds as if the second pot section on your radio is not working properly. This pot is connected as a voltage divider, connected as part of the large wirewound resistor on the side of the chassis. If you connect a voltmeter to the sliding contact of this pot section, you should see the voltage change by several volts as the pot is rotated. If you see no change, then either the pot is bad or there is an open section in the wirewound bias resistor.

If working properly you should have good control of volume level, even on a fairly strong signal.


Messages In This Thread
RE: Philco Model 20 volume control operation - by Mondial - 10-17-2013, 08:12 PM



Users browsing this thread:
[-]
Recent Posts
The list of my radio & TV collection!
Yes, Michael. But strangely enough, I managed to keep the original veneer. I must admit that I don't really like it, so ...RadioSvit — 02:21 PM
The list of my radio & TV collection!
Good radio. I bet there was a lot of veneer fixing.morzh — 02:16 PM
Philco 46-480 Electronic Restoration
>> it is because I am retired and a little demented. You have just the right amount of it. No perfectly sane p...morzh — 02:14 PM
The list of my radio & TV collection!
Old Zenith 5S-29 tube radio. First turn-on after repair and reception quality testing. Demonstration of the operation of...RadioSvit — 01:27 PM
Philco 42-345 Restoration/Repair
Welcome to the Phorum, osanders0311!  Regardless how far you intend to restore this set, first priority should be replac...GarySP — 11:51 AM
Philco 46-480 Electronic Restoration
Joseph, it is because I am retired and a little demented. My problem is that I wanted to own a collection that spans th...MrFixr55 — 11:29 AM
Philco 46-480 Electronic Restoration
Wow, here I am with only two restored radios. I’ve got to boost those numbers! If you can’t run with the big dogs, you m...jrblasde — 10:04 AM
Philco 46-480 Electronic Restoration
Hello MrFixr55, That will for sure keep you out of trouble! Last Sunday was spent mostly doing yard work anyway the we...radiorich — 09:50 AM
Philco 46-480 Electronic Restoration
Throw in all the Audio equipment that has to be kept in a bedroom (my office)L. 8 portable self contained PA speakers, ...MrFixr55 — 07:40 AM
Philco 42-345 Restoration/Repair
Looking at the pic supplied by Rod B, you can duplicate the missing loop antenna. 10 gauge copper wire can be used to m...MrFixr55 — 01:20 AM

[-]
Who's Online
There are currently 270 online users. [Complete List]
» 1 Member(s) | 269 Guest(s)
Avatar

>