1. The PHILCO Phorum
  2. Various and Sundry Categories
  3. Other Radios (Non-Philco)
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Threaded Mode
marconi 157
the picker
Member
***
Posts: 111
Threads: 2
Joined: Nov 2016
City: marystown nl canada
#1

11-19-2016, 11:00 AM
I picked a Marconi model 157 radio and when I got it the radio had a capacitor hum only so I recapped it and now I have a motor boating sound from half volume and up and no other sound only a low hum
Find
Phlogiston
Radio-Fixer-Upper
*****
Posts: 2,118
Threads: 112
Joined: Jun 2010
City: Medford OR (OR what?)
#2

11-19-2016, 11:51 AM
Assuming that all of the capacitors were installed correctly, check the values of all of the resistors in particular a canned-ohm if it has one.
"I just might turn into smoke, but I feel fine"
http://www.russoldradios.com/
Website Find
morzh
Odobenus rosmarus
*****
Posts: 15,823
Threads: 554
Joined: Oct 2011
City: Jackson, NJ
#3

11-19-2016, 12:47 PM
See if any tubes and their grid wires that are supposed to be encased in a shield are inside the shield.

Also: have you tested the tubes?
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.
Find
the picker
Member
***
Posts: 111
Threads: 2
Joined: Nov 2016
City: marystown nl canada
#4

11-19-2016, 01:57 PM
(11-19-2016, 11:51 AM)Phlogiston Wrote:  Assuming that all of the capacitors were installed correctly, check the values of all of the resistors in particular a canned-ohm if it has one.

I am not sure what a canned ohm resistor is but I will check the others
Find
the picker
Member
***
Posts: 111
Threads: 2
Joined: Nov 2016
City: marystown nl canada
#5

11-19-2016, 01:59 PM
(11-19-2016, 12:47 PM)morzh Wrote:  See if any tubes and their grid wires that are supposed to be encased in a shield are inside the shield.

Also: have you tested the tubes?
tubes have been tried in working radios and none of the tubes at all have shields
Find
Phlogiston
Radio-Fixer-Upper
*****
Posts: 2,118
Threads: 112
Joined: Jun 2010
City: Medford OR (OR what?)
#6

11-19-2016, 02:22 PM
(11-19-2016, 01:57 PM)the picker Wrote:  
(11-19-2016, 11:51 AM)Phlogiston Wrote:  Assuming that all of the capacitors were installed correctly, check the values of all of the resistors in particular a canned-ohm if it has one.

I am not sure what a canned ohm resistor is but I will check the others

It is the voltage divider resistor from which is derived the bias voltages. It is often a wire-wound in a metal sleeve riveted to the chassis for heat dissipation. The wire can burn open but most often the contacts become intermittent.

In most of my recent repairs, I would estimate that 1/2 to 2/3 of all resistors had either failed or were way out of tolerance.
"I just might turn into smoke, but I feel fine"
http://www.russoldradios.com/
(This post was last modified: 11-19-2016, 02:24 PM by Phlogiston.)
Website Find
KCMike
Phorum Expert
*****
Posts: 1,475
Threads: 69
Joined: Nov 2012
City: Kansas city, MO.
#7

11-19-2016, 02:29 PM
Here's schematic for anyone helping.
http://pacifictv.ca/schematics/marconi157data.pdf
Find
morzh
Odobenus rosmarus
*****
Posts: 15,823
Threads: 554
Joined: Oct 2011
City: Jackson, NJ
#8

11-19-2016, 03:25 PM
Russ might've meant Candohm.
It is a power resistor that is riveted to a chassis.


Ypi don't seem to have one.
Your neg bias seems to be made with a.... battery?
Is the battery good?
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.
(This post was last modified: 11-19-2016, 03:28 PM by morzh.)
Find
the picker
Member
***
Posts: 111
Threads: 2
Joined: Nov 2016
City: marystown nl canada
#9

11-19-2016, 03:42 PM
(11-19-2016, 03:25 PM)morzh Wrote:  Russ might've meant Candohm.
It is a power resistor that is riveted to a chassis.


Ypi don't seem to have one.
Your neg bias seems to be made with a.... battery?
Is the battery good?
are you talking about the 1.5 v bias cell if so yes I have it replaced
Find
sam
Phorum Expert
*****
Posts: 2,572
Threads: 337
Joined: Jun 2013
City: lawrenceville nj
#10

11-19-2016, 04:21 PM
candohm resister  looks like this
[Image: http://i117.photobucket.com/albums/o46/r...de8706.jpg]
could be smaller or larger with more tabs
Some day, and that day may never come, I will call upon you to do a service for me. But until that day, accept this justice as a gift
mafiamen2
Find
the picker
Member
***
Posts: 111
Threads: 2
Joined: Nov 2016
City: marystown nl canada
#11

11-19-2016, 04:29 PM
(11-19-2016, 04:21 PM)sam Wrote:  candohm resister  looks like this
[Image: http://i117.photobucket.com/albums/o46/r...de8706.jpg]
could be smaller or larger with more tabs

I will look but I do not think it has one
Find
sam
Phorum Expert
*****
Posts: 2,572
Threads: 337
Joined: Jun 2013
City: lawrenceville nj
#12

11-19-2016, 05:07 PM
I don`t think you have one
Some day, and that day may never come, I will call upon you to do a service for me. But until that day, accept this justice as a gift
mafiamen2
Find
the picker
Member
***
Posts: 111
Threads: 2
Joined: Nov 2016
City: marystown nl canada
#13

11-19-2016, 05:11 PM
(11-19-2016, 05:07 PM)sam Wrote:  I don`t think you have one
I looked and could not see one .
Find
Phlogiston
Radio-Fixer-Upper
*****
Posts: 2,118
Threads: 112
Joined: Jun 2010
City: Medford OR (OR what?)
#14

11-19-2016, 09:56 PM
Well, they look canned.

So never mind that, but check the voltages on the tubes starting with the 6F6.

Just curious too, does the eye tube do anything (signal indication)?

Do you have a signal tracer?
"I just might turn into smoke, but I feel fine"
http://www.russoldradios.com/
Website Find
Radioroslyn
Phorum Expert
*****
Posts: 7,286
Threads: 268
Joined: Dec 2009
City: Roslyn Pa
#15

11-19-2016, 11:41 PM
For us US guys here's some pic's of it:   http://radioatticarchives.com/radio.htm?radio=12521
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!

Terry
Find
« Next Oldest | Next Newest »




Users browsing this thread: 4 Guest(s)
[-]
Recent Posts
Mission Bell Model 19A Car Radio
Hello everyone,  As mentioned in my last post I was going to see if the vibrator / rectifier section could be persuaded...Antipodal — 08:21 PM
Philco 60 Squealing
Wondering if I did it backwards. If a coil was wound backwards, the oscillator would not work at all. Old school...Chas — 07:23 PM
Philco 38-7 Speaker
4-ohm speaker. Black, Green leads.tludka — 07:00 PM
Philco 42-390, code 121 speaker
#87 on the schematic.  This radio had a 8" Zenith  speaker attached to it when I got it. I do don't know the hist...Stevelog — 06:39 PM
Philco 60 Squealing
I'm pretty sure I now have the litz wire soldered. This did not make any difference. Back in April I rewound the seconda...dconant — 06:25 PM
Philco 38-7 Speaker
Just to make sure, you chose either 4 ohm into 5K or into 10K? (blk-org or blk-grn)morzh — 06:23 PM
Philco 38-7 Speaker
I have let this one sit because of other duties. Now I am back, and I have a couple of questions. I hooked up a Hammond ...tludka — 05:34 PM
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

[-]
Who's Online
There are currently 4820 online users. [Complete List]
» 1 Member(s) | 4819 Guest(s)
Avatar

>
  1. The PHILCO Phorum
  2. Various and Sundry Categories
  3. Other Radios (Non-Philco)