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

Loud hum when i turn on my Model 70
#1

All the tubes light up but all I hear is a loud hum. 

Adjusting the volume does nothing. 

Any ideas?
#2

First and foremost, DO NOT power up old radios until the capacitors and any drifted resistors have been replaced. Components in old radios degrade with age (especially capacitors), and can cause damage to other components (most which are much more expensive and harder to find). Caps are relatively inexpensive and replacing them will help keep other parts from being overloaded. Take care and BE HEALTHY! Gary

"Don't pity the dead, pity the living, above all, those living without love."
Professor Albus Dumbledore
Gary - Westland Michigan
#3

+1 what Gary said. Here's some more information courtesy of this site:

https://philcoradio.com/library/index.ph...urn-it-on/

Bottom line, your radio will need some components replaced under the chassis before it will play without that loud hum.

Greg V.
West Bend, WI
Member WARCI.org
#4

Welcome to the Phorum!
Icon_wave

The capacitor and resistor replacements are not too difficult especially if you have a little knowledge about soldering and electronics. If not, questions to the group here can help you through it or you can find someone to do the restoration for you.
#5

From what I have read, the hum is most likely caused by the old electrolytic filter capacitors. Those are very important and should be replaced.




Users browsing this thread:
[-]
Recent Posts
Zenith H725
The PSU filter cap arrived today (thank you USPS!) so I will work on that later. Meanwhile, I have the dial, speaker...EdHolland — 06:42 PM
Philco 610B oscillator wiring
Thanks Terry. After checking my notes I think I recorded about -10v at the 6A7 G4/control grid. The screen grid (G3 &...Tubester — 05:59 PM
The list of my radio & TV collection!
Magical chords of forgotten melodies, old nostalgic music on an old radio... Saturday night blues on the Mid-Waves on an...RadioSvit — 12:20 PM
Philco 42-345 Restoration/Repair
Thank you MrFixr55 the issue with this radio is that the internal coil antenna is missing and there was a wire in its pl...osanders0311 — 11:34 AM
Philco 610B oscillator wiring
Regarding the oscillator circuit which is comprised of the 6A7's cathode, control grid, and screen grid. These elements ...Radioroslyn — 10:33 AM
Philco 42-345 Restoration/Repair
Hi OSanders, First off, welcome to the Philco Phorum where Phine Phamily-Phriendly Pholks Phull of Philco Phacts and P...MrFixr55 — 08:41 AM
Philco 42-345 Restoration/Repair
Today I've been reading through the site trying to learn more about this radio. I also soldered the lose power cord cabl...osanders0311 — 08:24 PM
Philco 610B oscillator wiring
Thanks David! I do have that same later prodution model 610 schematic. I've also studied the Philco service bulletins fo...Tubester — 08:12 PM
Philco 610B oscillator wiring
Some info from Beitmans says late production. David   David — 06:06 PM
Restoring Philco 96
Oh wow! Just found this thread.  Brings me back to early days on this phorum.  I did a 96 back in 2017.  Thread here: ...rfeenstra — 06:05 PM

[-]
Who's Online
There are currently 2738 online users. [Complete List]
» 1 Member(s) | 2737 Guest(s)
Avatar

>