Need a new potentiometer

[Zink]

Hi, my Pandora's (Rebirth Edition) volume potentiometer has just failed. The left channel is not working (with built-in speakers too). I have made some checks to make sure that it's not any other thing, like the jack socket. It doesn't just produce noise on the left channel (like it did before, and cleaning helped back then), the channel is completely dead, with any position of the volume knob.


I have also found a similar potentiometer specs to see the internal connections, and 'fixed' mine with a 10k resistor between the two pads belonging to the broken section. And it kind of works - the left channel is working, but obviously not the same volume as the right channel. So it proves i's the potentiometer fault. (I'm writing this explanations to speed things up by skipping all suggestions of what might be wrong besides the potentiometer ).


Can you tell me what is the manufacturer and model number of the potentiometer? Perhaps if it could be bought from Mouser? (My company orders parts from Mouser from time to time, so I could avoid the shipping cost here). If not, how about selling me the potentiometer? I am able to solder it myself.


This is the message I have sent to ED a week ago, but he didn't reply. Too busy I guess. I was hoping that if I couldn't buy the potentiometer from an online shop, he would sell me one from his supplies.

 

[EvilDragon]

I'll try to catch up with most of my mails this week.


However, it sounds more like your headphone jack. Please reflow the solder and insert / remove the headphone a few times from the socket, maybe also use contact cleaner.


Sounds like the switch got stuck.


I've never seen a potentiometer fail like that - the sound would be scratchy, it's unlikely it completely fails.

 

[comradekingu]

Could measure the one you took out and then find one of those in the catalogue?


Will add name to http://pandorawiki.org/Audio_system if someone knows.

 

[asimov-solensan]

It really sounds like a problem with the jack connector I had the same problem for right channel and solved it in this thread:


https://boards.openpandora.org/topic/15413-right-speaker-broken//URL]

 

[levi]

But if he bridged the pot's inputs and outputs (on the problem side only) with a resistor, and sound came out, doesn't that isolate the pot as being the source of the problem, and excuse the jack?

 

[Zink]

But if he bridged the pot's inputs and outputs (on the problem side only) with a resistor, and sound came out, doesn't that isolate the pot as being the source of the problem, and excuse the jack?

Thank you.


Also before soldering the resistor I have checked the potentiometer with a multimeter* and found one pad that had infinite resistance to all other pads, that's how I know which exactly pad is broken (when you hold the Pandora so that you have SD slots pointing at your belly and you see the potentiometer pads, it's the leftmost pad).

I'll try to catch up with most of my mails this week.


However, it sounds more like your headphone jack. Please reflow the solder and insert / remove the headphone a few times from the socket, maybe also use contact cleaner.


Sounds like the switch got stuck.


I've never seen a potentiometer fail like that - the sound would be scratchy, it's unlikely it completely fails.

I too was suspecting the headphone jack at first, but I have checked the switches, and they work fine.


The potentiometer gave me scratches before, and a cleaning liquid has been helping then. But this time it's different - it stopped working at one moment when I was changing the volume.


If you're interested, after I have the potentiometer replaced, I will tear apart the broken one to see what happened, and post pictures here.


* - if voltmeter is a device to measure voltage, and multimeter is a device to measure various electrical values, what does potentiometer measure?

 

[TrashyMG]

* - if voltmeter is a device to measure voltage, and multimeter is a device to measure various electrical values, what does potentiometer measure?

The amount of energy it takes to wonder why it's called a potentiometer.

 

[Zink]

Any news on this? Can you at least tell me the part number of the potentiometer?

 

[levi]

The part number was probably listed here: https://boards.openpandora.org/topic/16425-the-day-the-pandora-goes-even-more-open//URL]


The link in that page to the right file seems to be broken though, although if I recall correctly, TrashyMG has already asked ED to fix that link for another purpose.  I don't seem to have kept the copy I downloaded back then.

 

[Zink]

Thanks, I didn't know about that page. Too bad the link isn't working.

 

[frefol]

The part number is R1001G21A1.  Here is a link to the manufacturers page http://www.song-huei.com/exec/product.php?mod=show&cid=53&pid=R1001G21A1&lg=E

 

[Zink]

Thank you. The full part number would most likely be R1001G21A1-B20K/φ16×2.8. I will contact the representatives of the manufacturer, that are close to me, and see if I can buy some.

 

[Zink]

Finally! I was able to order the potentiometers from a German distributor. Unfortunately they didn't have that exact model, but a very similar one - with smaller wheel and bent pins, so I had to do some pliers work. And now I have 10 of them just in case (they didn't want to sell me less).

It doesn't look beautiful, but it WORKS .

Thanks for your help.

The broken potentiometer apparently had a crack between the resistant layer and the pad. Though not visible, while measuring the resistance it suddenly went infinite when moving the probe by the track. So definitely not a wear problem. A random failure I would say.