Philco 37-611 Restoration (Newbie Here)
Posts: 10
Threads: 2
Joined: Nov 2013
City: Baltimore, Maryland
Hello to all ! Just completed recapping a Philco 37-611./ This is a transformerless receiver. I replaced the paper caps, the electrolytic caps, and both bakelite assemblies. I had to replace the on/off switch (and I'm guessing this is also some sort of tone control as well).
After powering up, (no smoke, no flames)  All of the tubes were glowing but no sound from the speaker. Just the slightest hint of a hum.
I took a measurement of all the tube voltages, hoping maybe one of the more experienced members could shed some light as to the cause of the problem using the tube voltage information.
They are as follows:
25Z6G
PIN 2 = -129.3
PIN 4 = +105.7
PIN 7 = -385.2
PIN 8 = +105.7
25A6G
PIN 2 = -385.3
PIN 3 = +1.23
PIN 4 = +1.23
PIN 7 = -310.5
PIN 8 = +7.04
6A8G
PIN 2 = -310.5
PIN 3 = +106.5
PIN 4 = +14.65
PIN 6 = +1.21
PIN 7 = -233.6
PIN 8 = +1.20
6K7G
PIN 2 = -112.2
PIN 3 = +106.9
PIN 4 = +14.87
PIN 7 = -232.2
PIN 8 = +14.02
6Q7G
PIN 2 = -0.1
PIN 3 = +103.8
PIN 4 = +10.7
PIN 5 = +13.34
PIN 7 = -111.2
Posts: 7,323
Threads: 270
Joined: Dec 2009
City: Roslyn Pa
So take your - lead from your meter and connect it to the off/on switch. set meter for DC volts. Measure the voltage on the pins of the 25A6 with the + lead . Report back.
Terry
Posts: 1,106
Threads: 88
Joined: Jun 2011
City: Tacoma
State, Province, Country: Washington
These voltages confuse me. This is obviously an early AA5 design and shouldn't have any voltages over about 125.
Posts: 10
Threads: 2
Joined: Nov 2013
City: Baltimore, Maryland
ok here are the new readings I got from neg lead on/off to 25A6 pins:
PIN 2 = +291.4 mV
PIN 3 = +3.14 v
PIN 4 = +3.14 V
PIN 7 = +1.35 V
PIN 8 = +8.84 V
Posts: 7,323
Threads: 270
Joined: Dec 2009
City: Roslyn Pa
Ok so far you have no HV. Measure the voltages on the pins of the 25Z6.
Terry
(This post was last modified: 11-30-2013, 11:58 PM by Radioroslyn.)
Posts: 10
Threads: 2
Joined: Nov 2013
City: Baltimore, Maryland
25Z6
PIN 2 = +42mv
PIN 4 = +108.6v
PIN 7 = +292mV
PIN 8 = +108.6V
Posts: 7,323
Threads: 270
Joined: Dec 2009
City: Roslyn Pa
Good, You have HV coming out of the rectifier tube. So the next thing is the field coil #48 and choke #51. Check for resistance on both parts. Bet 51 is open.
Terry
ps Welcome to the Phorum! Hope you enjoy your stay!
(This post was last modified: 12-01-2013, 07:02 PM by Radioroslyn.)
Posts: 10
Threads: 2
Joined: Nov 2013
City: Baltimore, Maryland
the reading on part # 51 choke is 374 ohms. Not sure where to take the reading for the field coil. Is it part of the audio transformer assembly?
Perhaps you could point it out in this photo?
Posts: 1,114
Threads: 14
Joined: Feb 2013
City: Irvington, NY
The field coil is connected to the black and yellow wires going to the terminals on the transformer. You can see the wires enter the coil itself which is located at the center of the back of the speaker.
Posts: 10
Threads: 2
Joined: Nov 2013
City: Baltimore, Maryland
Thanks for the info, Mondial, the field coil reads at 2750 ohms.
Posts: 7,323
Threads: 270
Joined: Dec 2009
City: Roslyn Pa
So with the - connected to the off/on sw what DC voltage do you see at pins 3 and 4 of the 25A6??
Terry
Posts: 10
Threads: 2
Joined: Nov 2013
City: Baltimore, Maryland
Pin 3 = 1.7 vdc
Pin 4 = 1.7 vdc
Posts: 813
Threads: 43
Joined: Dec 2008
City: Chicago, IL
Where are you connecting the negative lead of your meter when checking voltages ? The chassis on this set is not ground - it's floating.
Posts: 10
Threads: 2
Joined: Nov 2013
City: Baltimore, Maryland
I have been connecting it to the on/off switch
Posts: 813
Threads: 43
Joined: Dec 2008
City: Chicago, IL
Oh, OK. I' still puzzled by your first post with voltages as high as -385 ?
Users browsing this thread: 1 Guest(s)
|
|
Recent Posts
|
|
Philco P45-6365 Universal Transformer Instruction Manual
|
| Can anyone guide me to where this may be found?GRG — 03:00 PM |
|
54C Complete Teardown/Rebuild
|
| I don't think that I have encountered a 12Z3 before, curious how it uses one of those but includes a #43, which is a 25 ...Arran — 02:17 PM |
|
HiFi (Chifi) tube amp build - but my own design.
|
| It's the other forum. I'm also in DIY, but mostly read there. Honestly, I kinda jumped into this without much thought to...TV MAN — 10:43 AM |
|
Philco 71 Code 125
|
| Hello,
I am in need of a schematic for this radio. Mine has the three separate circular tube shields and a shadow me...dconant — 08:06 AM |
|
Stromberg Carlson 1500 Squeal
|
| And life just keeps getting more complicated.dconant — 07:57 AM |
|
54C Complete Teardown/Rebuild
|
| Hello Roy,
here is this one
sincerely Richardradiorich — 12:45 AM |
|
54C Complete Teardown/Rebuild
|
| Richard,
Had grabbed it already but thank you just the same. I find myself wanting to find some way to block out the...glyphmon — 12:03 AM |
|
54C Complete Teardown/Rebuild
|
| Hello roy,
here is a link to the schematic .
Sincerely Richardradiorich — 11:54 PM |
|
54C Complete Teardown/Rebuild
|
| Richard,
The Silvertone 2014 also is a transformerless set, so I am incorporating a 1:1 600 ohm audio isolation transfo...glyphmon — 11:37 PM |
|
Preliminary work on wife's Silvertone 2014
|
| Did an alignment today which was interesting. IF alignment went great, almost all was already spot-on. Adjusting on th...glyphmon — 11:35 PM |
|
Who's Online
|
There are currently 2359 online users. [Complete List]
» 1 Member(s) | 2358 Guest(s)
|
|
|
|
 
|
![[-]](https://philcoradio.com/phorum/images/bootbb/collapse.png "[-]")
