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Hi i have speakers labtec arena 530 . i opened the main speaker and the problem is from the potentiometer I can make a brigde and connect 2 pot of the potentiometer sound become clean but i loose the volume control

how to know if it's dead or just dirty and can be cleaned ? and can i find the same potentiometer if it's dead (there is no réference . i found the same look potentiometer in the internet but it seems not having the same size ( pot found : circular 16*2 mm | pot i have 20 * 3 mm )

Thank you for help !! enter image description here

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    \$\begingroup\$ Questions on the repair of consumer electronics, appliances, or other devices must involve specific troubleshooting steps and demonstrate a good understanding of the underlying design of the device being repaired. \$\endgroup\$ – Marcus Müller Nov 16 '20 at 20:42
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    \$\begingroup\$ How to know if it is dirty or dead? Try cleaning it first. If it helps, it was dirty. If it did not help, it's dead. \$\endgroup\$ – Justme Nov 16 '20 at 20:47
  • \$\begingroup\$ yes obvious , i have to get the cleaner before . i don't want to f*** all the system with wrong cleaner :) \$\endgroup\$ – na7la Nov 16 '20 at 22:29
  • \$\begingroup\$ @MarcusMüller . i took them to professionel in my area and no one wanted to make efforts to repair them . they tell me it's an old model and it's dead . that's not cool . and as a noob i find the problem by my self (accidentely sure ) . it's not that difficult for a professional to fix it but in countries like mine , 90% of the time you must to diy/fix things buy your self even it's not your area of your competence . and sincerly internet really help . \$\endgroup\$ – na7la Nov 16 '20 at 22:34
  • \$\begingroup\$ @na7la I do agree, but that doesn't make the question on-topic for this site \$\endgroup\$ – Marcus Müller Nov 17 '20 at 9:18
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Given the low cost of these products, they use the cheapest parts that fit and those are hard to find. The wiper is unlikely to be gold plated so oxidation can occur then gets cleaned by friction. Excess friction removes the metalized layer on the plastic film, assuming most likely cheap, metal film pots.

They suffer from frequent use , dust and corrosion. Better quality pots are cermet. Wire wound are more expensive low R values and unlikely to be used there, and carbon film also exist.

If spray or pouring alcohol electrical cleaner doesn't work , replace it with fixed R's and forget it. Using common Isoprop. has some residue that may work or not.

If you are persistent, you can find one of a similar value and wire it up so it works with some persuasion and creativity. How creative are your searches and how much is it worth? Value Village sells these systems for about $10.

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  • \$\begingroup\$ thanks for help , but a little bit too technic for me . from what i understood , your advice is to change another kind of pot with better quality ?? yes i would do that but i must have the same one . so i can close the speaker and get the volume control back \$\endgroup\$ – na7la Nov 16 '20 at 21:41
  • \$\begingroup\$ Wiggle it . static? maybe broken solder joint? pour isopropyl alcohol then dry it, still bad? short out the pot or set and forget it with tape. \$\endgroup\$ – Tony Stewart EE75 Nov 16 '20 at 21:58
  • \$\begingroup\$ it back to work when i put a screw driver between pin 3 & 4 but i loose the volume control . i thought to solder them together and to control volume with computer . but it's better if i find the potentiometer . i will try to clean with isopropyl alcohol will buy it tommorow , thx for help \$\endgroup\$ – na7la Nov 16 '20 at 22:06
  • \$\begingroup\$ Isopropyl alcohol washes dirt away, but also leaves the pot dry, so it might not be the correct chemical to clean pots. There are special pot cleaning fluids available that leaves the pot contacts with oily layer that prevents wear and oxidation. \$\endgroup\$ – Justme Nov 16 '20 at 22:10
  • \$\begingroup\$ sure WD40 works for me \$\endgroup\$ – Tony Stewart EE75 Nov 16 '20 at 22:21
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Measure the resistance

Turn the potentiometer all the way to one side and measure the resistance two times. The first time measure between the middle and one pin and the second time measure between the middle pin and a different pin. One of the values should be close to 0, and the other should be nearly the resistance of the pot (So 10k for a 10k resistor).

Results

If you are getting values that are lower than they should be or if there is noise/inconsistent readings the potentiometer might be dirty and you should probably clean it (or honestly if it is just a normal pot, buy a new one they are dirt cheap. no pun intended).

If your values are virtually zero for both of the readings chances are your potentiometer is extremely dirty or, more likely, damaged.

EDIT: Looking at your picture it doesn't look like a classic 3 pin pot so you should try to reference the datasheet and see which pins are which. Also, it does look very dirty so my best guess is to use some isopropyl alcohol and clean the outside and inside if possible. As stated earlier I suggest just seeing if there is a replacement part (Because it doesn't look too expensive) and just replacing it all together.

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  • \$\begingroup\$ i will try to measure to see the values . it's not a 3 pinpot , it's 5 pin pot . it will be cool if i find where to buy it , it will be better but i want to have the same one ( there is no reference on it , and there is tons of models on the net , i don't want to buy a wrong one . i found ones that looks similar but i'm not sure it have the same size . i didn't find the datasheet it's a very model , i bought it 15 years ago and it's not a famous brand. thanks your help is precious \$\endgroup\$ – na7la Nov 16 '20 at 21:34
  • \$\begingroup\$ @na7la No problem! If you could upload a better picture (less blurry) with more details (model number of some sorts etc) I might be able to help you find a part. \$\endgroup\$ – Jared Cohen Nov 17 '20 at 22:38

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