Understanding wiring of On/Off switch + Potentiometer combination

Thread Starter

Madaxle

Joined Jul 23, 2021
2
I'm in the process of building a Halloween prop using an old 1970's Sony Trinitron TV, and I was hoping to be able to use the original power switch to power my prop, and use the integrated volume control as a dimmer for my LEDs I'm going to wire to it. (Basically I would like to wire an LCD monitor to the on/off switch and the LEDs to the potentiometer.) The only problem is that I have no clue which wires do what. Any ideas?
(Its a D50KΩ Potentiometer that says "NOBLE" on the back and looks like its from a company called Uno Labs if this helps any.)IMG_1818.jpgIMG_1822.jpg IMG_1821.jpg
 

LesJones

Joined Jan 8, 2017
3,497
Your first picture shows the potentiometer connections. The center connection is the wiper.the top connection is the end of the track when the knob is turned fully anticlockwise. The bottom connection is the end of the track when the knob is turned fully clockwise.
I am making the assumption that the switch has only two states controlled by a single push button (Which may be the knob.) or a second knob with just two positions..
You last picture is the switch connections. I suspect one pole is red to blue and the other pole is red to grey. It is also possible that when one pole is open the other pole is closed. To confirm the way the switch works you will have to break the connection between the two terminals connected to the red wire and then do continuity tests.

Les.
 

MisterBill2

Joined Jan 23, 2018
9,292
It is not likely that using a volume control variable resistor will work very well for controlling LED intensity. The resistance is probably far to much, and the power handling rating far to low.
 

LesJones

Joined Jan 8, 2017
3,497
What MisterBill2 says is correct. I was assuming the potentiometer was being used to set the output of a constant current circuit or a PWM controller. Another problem is the volume control potentiometer will have a logarithmic track characteristic rather than linear.

Les.
 

MisterBill2

Joined Jan 23, 2018
9,292
The witch should be OK for controlling the mains power to the monitor, the 50K ohms pot would work for controlling a PWM dimmer for the LEDs, and my guess is that the monitor will replace the original picture tube in the same case. That may be an interesting show when it is completed.
Probably the four terminals on the switch include a screen blanking feature to eliminate the spot in the middle that used to be a problem when CRT tvs were switched off.
 

Thread Starter

Madaxle

Joined Jul 23, 2021
2
Your first picture shows the potentiometer connections. The center connection is the wiper.the top connection is the end of the track when the knob is turned fully anticlockwise. The bottom connection is the end of the track when the knob is turned fully clockwise.
I am making the assumption that the switch has only two states controlled by a single push button (Which may be the knob.) or a second knob with just two positions..
You last picture is the switch connections. I suspect one pole is red to blue and the other pole is red to grey. It is also possible that when one pole is open the other pole is closed. To confirm the way the switch works you will have to break the connection between the two terminals connected to the red wire and then do continuity tests.

Les.
It works! Thank you for the help. I did a continuity test on the poles like you said and I was able to figure out what poles did what. I was also worried about there being too much resistance using a 50K switch like MisterBill2 stated, but to my surprise, everything lit up and dimmed just fine. I will definitely need to put a limit on how bright they get though so I don't burn the little LEDs out haha.
 
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