It's been a while... FOUND
Posts: 825
Threads: 113
Joined: Aug 2012
City: The Villages
State, Province, Country: Florida
Since I've run across a problem like this. I have a 49-905 that I just finished replacing all the electrolytic and paper capacitors. All tubes and resistors check ok. My problem is a hum. It gets louder with the volume control but never over powers a station. I checked all the wires and they appear to be dressed as original. Even though the tubes tested good I swapped them out 1 by 1 with no difference.
Any help will be appreciated.
Schematic
Thanks,
Eric
The Villages, FL
Member: Philco Phorum, ARF, ARCI & Radiomuseum.org
(This post was last modified: 10-03-2015, 05:04 PM by Eric Adams.
Edit Reason: spelling
)
Posts: 15,822
Threads: 554
Joined: Oct 2011
City: Jackson, NJ
Eric
Hum can be anything.
Does it change with tuning or stays constant?
Now, often it is a result of bad ground. Look at rivets holding ground leaves where wire solder to. These are often the culprits.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Posts: 825
Threads: 113
Joined: Aug 2012
City: The Villages
State, Province, Country: Florida
It stays constant, but it doesn't drown out a station when I tune it in. It kind of stays in the background.
One more thing I forgot to mention. When I first got it completed, there was no hum. I aligned both AM and FM without a sound. I put it in the cabinet and played it for about 15 or 20 minutes and then it started. Does that help?
Eric
The Villages, FL
Member: Philco Phorum, ARF, ARCI & Radiomuseum.org
Posts: 7,286
Threads: 268
Joined: Dec 2009
City: Roslyn Pa
Hey Eric,
I'd try swapping the tubes you may have gotten a cathode to control grid short internally in the tube. Higher voltage heater tubes are a little more suspect than others. As Mike said check grounds is good too.
Terry
Posts: 825
Threads: 113
Joined: Aug 2012
City: The Villages
State, Province, Country: Florida
Thanks, Terry. Tube swap has been tried. I'm just going to check all the grounds and recheck all of my solder joints.
I'll let you guys know how it turns out.
Thanks,
Eric
The Villages, FL
Member: Philco Phorum, ARF, ARCI & Radiomuseum.org
Posts: 825
Threads: 113
Joined: Aug 2012
City: The Villages
State, Province, Country: Florida
Well, I took it off of the punishment shelf for another look. I tried tube swaps again. It was the 19C8! I replaced it and the hum was completely gone.
Thanks for your help everyone. 
Eric
The Villages, FL
Member: Philco Phorum, ARF, ARCI & Radiomuseum.org
Posts: 1,562
Threads: 56
Joined: Nov 2008
City: Sedona, AZ/Placentia/CA
Congrats Eric, one more off the punishment shelf.
Jerry
A friend in need is a pest! Bill Slee ca 1970.
Posts: 5,088
Threads: 270
Joined: Nov 2012
City: Wilsonville
State, Province, Country: OR
Users browsing this thread: 1 Guest(s)
|
|
Recent Posts
|
|
Philco 42-390, code 121 speaker
|
| >>A closer examination of the very small print schematic indicates that the speaker is a PM type.
This shows a ...morzh — 05:18 PM |
|
Philco 60 Squealing
|
| Litz is typically tinned by simply rubbing it with the soldering iron tip while immersed in solder (and a bit of rosin f...morzh — 05:14 PM |
|
Philco 6K7
|
| The suppressor grid (if by G3 you mean the S) is usually at the Cathode potential, which in this caes is GND.
I am not ...morzh — 05:10 PM |
|
Philco 16B Parts
|
| Thanks for the reply. Unfortunately the radio was removed before bidding was over so I didn't get a chance to bid.dconant — 04:10 PM |
|
Philco 16B Parts
|
| Hi Dan,
Mike is correct, there's a lot of painted stuff on the chassis but it looks pretty good. The sm is all there,sp...Radioroslyn — 03:50 PM |
|
1930s Stromberg-Carlson Tombstone Radio need help identifying model number
|
|
Hi Cap'n Clock,
Unfortunately, I do not have this radio. This is a shame because this should be a good performer. 2A...captainclock1988 — 03:43 PM |
|
Philco 42-390, code 121 speaker
|
| Using a 5W 1.5k ceramic resistor in place of the field coil and using a 4 ohm PM speaker, I was able to bring the radi...Stevelog — 02:57 PM |
|
Philco 60 Squealing
|
| I have taken out the 2nd IF and found a problem or not. I believe the coils are litz wire. There is a very small strand ...dconant — 02:13 PM |
|
Philco 6K7
|
| I am restoring a Philco 37-60. The am reception is very good, but the shortwave is very weak. Run 6 Philco removes the g...bobbyd1200 — 01:35 PM |
|
1930s Stromberg-Carlson Tombstone Radio need help identifying model number
|
| Hi Cap'n Clock,
Unfortunately, I do not have this radio. This is a shame because this should be a good performer. 2A5...MrFixr55 — 06:48 AM |
|
Who's Online
|
There are currently 4290 online users. [Complete List]
» 4 Member(s) | 4286 Guest(s)
|
|
|
|
 
|
![[-]](https://philcoradio.com/phorum/images/bootbb/collapse.png "[-]")
