Fixing 931 bt volume potentiometer

ny935

Member (SA)
Jan 26, 2019
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I picked up this model for a good price in excellent condition with remote. The problem is the volume doesn't want to go down with the volume knob, only goes up when turning down. Works fine with remote. This has one of those infinite knobs that just keeps turning. Can it be cleaned like the older pots that have a min. And max. Setting? Worst case I have nothing to lose by trying.
I used it for family Christmas gathering. Volume at max and just controlled the volume from my phone which was sending the bt signal. Worked great and family loved it.
By the way it sounded like it was under a seat cushion when I first played it. Very disappointed. Then I found the eq button on remote and turned on loudness. This thing came alive!! Very pleased with the box. My sixth Lasonic. Is this one of the rarer models? It grew on me, the silver color.
 

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Superduper

Member (SA)
Those don't use potentiometers. They use digital encoders. The only similarity they share with pots are that they have a shaft to mount a knob. The encoder expresses digital pulses to a MPU depending upon which direction the knob is turned to let the controller know you are wanting that function to go up or down.
 

ny935

Member (SA)
Jan 26, 2019
114
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Thanks super. You have a perfect name for this site. So it's not serviceable. Similar to the tdk volume issues. At least I have the remote.
Still cooler than any other Bluetooth box
 

Superduper

Member (SA)
Like you said, it may be worth a try cleaning, there’s nothing really to lose since it’s broke. Really depends though on the design. There’s several different kinds of encoders. Also, they can be changed if you can find a matching one. By matching, I’m not saying pin location or physical looks either. Best bet, take a look at it & get the component ID# & see if you can find one. If nothing else, you might be able to find the datasheet for the specs to find a compatible one. Oh it’s also possible that one of solder joints fractured. These are almost all PCB mounted and lots of use & pressure could fracture a joint.
 

Transistorized

Member (SA)
Jun 19, 2012
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On a good note, there is a work around for you with the remote. Another one is the volume board is its own little section with a connector.

Below picture from Radio Active's Free parts sale
IMG_20170202_133314875.jpg

Might check to see that the wired connection to the daughter board is secure with no pinched or broken wires. If that looks good and you checked for cracked joints as superduper suggested, give the unit a quick blast of deoxit. If it doesn't work then no big deal. As superduper said, it didn't work anyway :-)
 

ny935

Member (SA)
Jan 26, 2019
114
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Thanks for the info transistorized, and the pic, is that currently in the for sale section? I don't have access yet.
And Super, I'll check those sites after I open it up and see what's happening. I've read in other posts that these had loose wires since new.
 

ny935

Member (SA)
Jan 26, 2019
114
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Of course it has. Lol. I'm up to 24 post now. Soon I can access the for sale section. See what's there.