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

Philco 42-1013
#1

Have this thing re-capped now and it does play.
I don,t seem to have the volume I would like,and if you turn it up to about 1/2 volume it starts getting distorted and the volume does not really go up.
Someone replaced the volume switch with a combe on/off/volume switch due to a bad switch on the off pushbutton.
I wonder if the switch is under-rated for that chassis,or if there could be something else I should be looking at like maybe a tube?
This one has been a bear for a newbie like me to work on.
Any idea's?
Thanks again,
murf
#2

You picked a difficult set to start out. As far as distortion, I would make basic voltage checks in the audio section with emphasis on the audio output bias. Should be about -20V on the control grids of the 7C5s. Also make voltage readings on the other tubes in the radio too. Often problems can be found this way without elaborate test equipment. If basic voltage checks are good then alignment will have to be considered.

Concerns about a under-rated switch is misplaced. Tubes are usually Ok. These being locktal tubes there is concerned about pin connection issues. Rocking the tubes in the sockets can reveal a intermittent pin while listening to the radio.

http://www.nostalgiaair.org/Resources/497/M0013497.htm
#3

rghines1 Wrote:You picked a difficult set to start out. As far as distortion, I would make basic voltage checks in the audio section with emphasis on the audio output bias. Should be about -20V on the control grids of the 7C5s. Also make voltage readings on the other tubes in the radio too. Often problems can be found this way without elaborate test equipment. If basic voltage checks are good then alignment will have to be considered.

Concerns about a under-rated switch is misplaced. Tubes are usually Ok. These being locktal tubes there is concerned about pin connection issues. Rocking the tubes in the sockets can reveal a intermittent pin while listening to the radio.

http://www.nostalgiaair.org/Resources/497/M0013497.htm


Voltages were checked as well as audio output.All seem fine.
Have had tubes out for cleaning and testing.
Is there a way to check the volume switch that was replaced?
Thanks for the help.
murf
#4

Little hard to read the schematic. Thinks it reads 2 Meg total with a 1 Meg tap. Believe the tap is for improving bass at low volume. Beginning to think the volume control replacement was poorly executed. Verify resistance and presence of a tap on the replacement and associated wiring. Not unusual to see poorly done vintage repairs for parts shortages, etc. Might find a replacement if needed from Mark Oppat at oldradioparts.net.
#5

rghines1 Wrote:Little hard to read the schematic. Thinks it reads 2 Meg total with a 1 Meg tap. Believe the tap is for improving bass at low volume. Beginning to think the volume control replacement was poorly executed. Verify resistance and presence of a tap on the replacement and associated wiring. Not unusual to see poorly done vintage repairs for parts shortages, etc. Might find a replacement if needed from Mark Oppat at oldradioparts.net.


Will check it out when I can.
Thanks again




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Kurt P
Terry, gotcha, thanks for the clarification.  That’s probably why the speaker seems shorted.  Assuming the OT/FC/speaker...Kurt P — 10:59 AM
Radiola 18 Amplifier & PS
I have the 2.25V and 2.5V information confused, and must look more carefully at the schematic and Hammond transformer in...TN Allen — 10:24 AM
Radiola 18 Amplifier & PS
Thank you for the information, it all helps, although understanding some of it takes time. One reason for doing the PS a...TN Allen — 09:42 AM
462ron
Hi Mike, the radio is coming along nicely but wow, you must have some serious moisture in your shop judging by the amoun...462ron — 06:29 AM
Restoring Philco 37-604C
Have rebuilt the can. The can had 4 caps in it, 2x16uF, 10uF and 8uF. I used a 15uF as the first cap, 22uF and 10uF ...morzh — 09:38 PM
Philco 89B code 123 newbie
The flat copper wires are from the hum bucking coil. All of the other resistances seem to be OK.Radioroslyn — 04:15 PM
Help with weston 669
I need help with my 669 meter. I recapped it becausing it was pegging the meter out. Now the neon light comes on (not su...daveone23 — 02:42 PM
Philco 89B code 123 newbie
I may be incorrect but you should measure around few ohms for the voice coil. In addition you may have a hum bucking coi...RodB — 02:29 PM
Philco 10 car radio head key
I recently acquired a 1932-33 Philco 10 Transitone car radio. The head has a key slot and the key is missing. I found a ...Keandkafu — 01:33 PM
Philco 89B code 123 newbie
Well it looks like I jumped the gun.  :lol:   Brought it up slowly on a variac and at about 30V it was drawing .24A and ...Kurt P — 12:30 PM

[-]
Who's Online
There are currently no members online.

>