Replacing potentiometers on vintage record player - PLEASE HELP.

Thread Starter

mkprsn

Joined Sep 3, 2020
5
I'm trying to replace the poteniometers 1no Volume and 1no Tone on a 1970s Sonorama M390 vintage record player.

Im struggling to find the right components, or even where to start with this. (few images included below)

Volume: 1M Ohms B (as printed on the component), I'm unsure what Wattage this will be for a replacement part.
Tone: 2K2A (as printed on the component), I have no idea what this means.

Having tested the current on both potentiometers, the volume one seems fine but there's no current running through the tone. If I'm going to replace the once I may as well replace both.

Please could someone give me advice as I literally have no idea whats going on and I'm really struggling.
IMG-8977.jpgIMG-8975.jpgIMG-8973.jpg
 

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AlbertHall

Joined Jun 4, 2014
10,576
Having tested the current on both potentiometers, the volume one seems fine but there's no current running through the tone. If I'm going to replace the once I may as well replace both.
If you have a multimeter, with the power off, connect the meter between one end connection and the centre connection. The measured resistance should change smoothly between zero and the pot value (1M or 2.2k). Repeat this measurement centre to each end for each section of each pot.
 

Thread Starter

mkprsn

Joined Sep 3, 2020
5
Are both sections of the potmeters on the same axis?
If so they are stereo potmeter
They are both wired onto the top three terminals of each pot? .. not sure if this means theyre on the same axis. It is a mono record player with only one speaker don't know if this has anything todo with the pots being stereo or not
 

bertus

Joined Apr 5, 2008
20,889
Hello,

On a stereo potmeter both sections are moved by one axis:

Stereo potmeter.png

On a dual potmeter the sections can be moved independend by the two axis that are over each other:

Dual potmeter.png
The thin axis will move the back potmeter.
The copper colored axis will move the front potmeter.


Bertus
 

Thread Starter

mkprsn

Joined Sep 3, 2020
5
Hello,

On a stereo potmeter both sections are moved by one axis:

View attachment 216309

On a dual potmeter the sections can be moved independend by the two axis that are over each other:

View attachment 216308
The thin axis will move the back potmeter.
The copper colored axis will move the front potmeter.


Bertus
In that case to answer you're question from earlier -Yes they're both fixed on the same axis as the first picture shows. :)
 
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