Function Knob Turning Pulse Noise After Long Time Non-Use ?

[BOBRR]

Hello,

Have a SDS 200 which was purchased when they first became available.

Due to medical issues, haven't used it for probably close to a year now.

Seems to work, but-

Turning the Function knob, even a little, results in a (considerable) noise burst/ noise pulse.
True for headphones or speaker output.

Sometimes true for the volume knob also, but not 100 % of the time like the Function knob.

Has there been any history of the Pots they used going bad ?

Or, might there be some other reasonable explanation ? Any tests, etc. I can perform ?
Something i can correct by myself possibly ?

Or, is this something where the unit should be returned to Uniden ?
If so, is there a link describing how to do it, cost, etc. ?

What's their (typical) turn around time ?

Any thoughts would be most appreciated.

Thanks,
Bob

 

[darkness975]

That's unusual.
I wonder if something inside there is off balance / crooked / etc. and causing temporary additional pressure on other components when touched.

 

[Chronic]

Everyday there seems to be a new oddity with the sds's

 

[Ubbe]

Turning the Function knob, even a little, results in a (considerable) noise burst/ noise pulse.
True for headphones or speaker output.

Out from the factory they have a grounding issues that creates signal loops between front panel and main scanner. It creates hum and anything changing the voltage levels to ground will ride on the audio from the front panel.

I suggest you do the modification that Uniden forgot about and ground the circuit board inside the front panel, the hum problem solution.

/Ubbe

 

[crippledchicken]

Sounds like the knob contacts have gotten oxidized/corroded rotating back and forth quite a few times will burnish the contacts and allow proper function sometimes, I've used Caig Deoxit contact cleaner a lot with good results on numerous electronic components. Oh, and the Static Discharge mod works wonderful!

 

[iMONITOR]

I don't think the control mechanism is a potentiometer or a rotary switch. It's likely optical encoder. You might not want to spray it with anything until you can confirm what type of device it is! Uniden hopefully will respond.

 

[crippledchicken]

I see, didn't know that Thanks!

 

[Ubbe]

I don't think the control mechanism is a potentiometer or a rotary switch. It's likely optical encoder.

Uniden doesn't use those kind of expensive components. It's a mechanical switch for sure, and they all seem to suffer from material quality issues.

/Ubbe

 

[iMONITOR]

Uniden doesn't use those kind of expensive components. It's a mechanical switch for sure, and they all seem to suffer from material quality issues.

/Ubbe

Learn something everyday. I've probably owned over twenty Uniden scanners using that type of control and never a problem. First time I even heard of someone else having one either. I guess I need to get out more. Thanks for the info!

 

[fxdscon]

Apparently, Uniden does use rotary encoders of some sort... at least on some scanners.

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.

 

[Ubbe]

I've probably owned over twenty Uniden scanners using that type of control and never a problem.

The older scanners never had a problem. My BCT15's and UBC780 never skips a beat in their controllers but the 536 went bad after a year and the lettering on the rubber buttons wears off quickly. I've seen messages about the rotary mechanical encoder go bad in all of Unidens latest scanners. I guess Uniden needed to keep costs down when they have complicated firmware to develop and give away free updates with new features that takes bites off the profit account.

/Ubbe