Voltage Sensor Problem?

V

V65MagnaFan

Guest
Hi,

This query refers to a Uniden Bearcat BC-235xlt scanner. I suspect that the
radio has a defective voltage sensor.

Charged overnight, even a new battery sets off the low battery signal after
only a couple of hours. Yet, by slapping the bottom of the unit once or
twice, the voltage sensor turns off, thereby giving me extra hours of
battery use.

So, is it worthwhile to open the radio? Am I able to adjust the voltage
sensor easily at the board?

Short of returning the unit to Uniden, is there anything I can do to repair
the unit?

TIA
 
"V65MagnaFan" <v65magnafan@nowhere.com> wrote in message
news:Xtphb.269947$Lnr1.194812@news01.bloor.is.net.cable.rogers.com...
Hi,

This query refers to a Uniden Bearcat BC-235xlt scanner. I suspect that
the
radio has a defective voltage sensor.

Charged overnight, even a new battery sets off the low battery signal
after
only a couple of hours. Yet, by slapping the bottom of the unit once or
twice, the voltage sensor turns off, thereby giving me extra hours of
battery use.

So, is it worthwhile to open the radio? Am I able to adjust the voltage
sensor easily at the board?

Short of returning the unit to Uniden, is there anything I can do to
repair
the unit?

TIA

Sounds like an intermittent connection, if all the battery contacts are
Click to expand...
clean it would probably be inside. If you continue the "Slap" routine you
may well damage something else.

--
Regards ............... Rheilly Phoull
 
Right. I understand that.

I was hoping that someone familiar with the unit could guide me through the
circuit board, perhaps to find a pot that regulates the V sensitivity.

I opened the unit today and saw no such pot. I also saw no cracks, splits,
or defects.

Then again, I'm not an expert.

Any ideas?
 
From your description, I would agree that it sounds like an intermittent
connection or oxidized battery contact. An easy thing to do is to clean the
battery contacts with some light abrasive (fingernail file or emery cloth).
Oxidation on the contacts isn't always visually obvious.

It is unlikely that the "voltage sensor", as you put it, is malfunctioning
because that is generally a hard-wired voltage threshold detection circuit
or a firmware-programmed threshold using some sort of analog-to-digital
conversion depending on the age and model of the scanner--neither of which
would drift (especially if smacking the unit changes things--that's
DEFINITELY a sign of intermittent connection). In other words, there
probably isn't any kind of adjustment you can make. You're going to have to
track down the intermittent connection.

If you have a cold solder joint, for instance, where the battery contact is
soldered into the circuit board, it also may not be visually obvious to the
untrained eye. If you're confident enough, you could try re-flowing any
questionable solder joints with a low power soldering iron.

But first, as I said before, clean ALL of the battery contacts. That's easy
and quick, and has a reasonable likelihood of being the problem. Let us
know if that works.

- Doug


"V65MagnaFan" <v65magnafan@nowhere.com> wrote in message
news:ceGhb.165706$3r1.146974@news02.bloor.is.net.cable.rogers.com...
Right. I understand that.

I was hoping that someone familiar with the unit could guide me through
the
circuit board, perhaps to find a pot that regulates the V sensitivity.

I opened the unit today and saw no such pot. I also saw no cracks, splits,
or defects.

Then again, I'm not an expert.

Any ideas?
Click to expand...
 
In article
<iYHhb.49282$Ri4.19386108@news4.srv.hcvlny.cv.net>,
dougslug@hotmail.com says...
An easy thing to do is to clean the
battery contacts with some light abrasive (fingernail file or emery cloth).

I suggest extreme caution using this method, and using this
Click to expand...
method only when corrosion or foreign matter is clearly
visible.

The use of any sort of abrasive may result in the removal of
the plating from the battery contacts. Once the plating is
gone, the pot metal underneath does a Very poor job of
conducting. The only fix is to put a layer of solder on the
pot metal, and gently file It down to a flat surface.

Cleaning terminals that don't show significant crud can be
performed with an electronics cleaner or alcohol and a
cotton swab or rag, or perhaps the eraser of a #2 pencil,
which does have a light abrasive quality to it, but would
take serious effort to remove the plating.

--
Mark

The truth as I perceive it to be.
Your perception may be different.

Triple Z is spam control.
 
Good points, Mark. Better to go easy on the contacts at first.


"Mark" <ZZZmark@whiskey-creek.net> wrote in message
news:MPG.19f1f0742f3f472989789@newsgroups.bellsouth.net...
In article
iYHhb.49282$Ri4.19386108@news4.srv.hcvlny.cv.net>,
dougslug@hotmail.com says...
An easy thing to do is to clean the
battery contacts with some light abrasive (fingernail file or emery
cloth).

I suggest extreme caution using this method, and using this
method only when corrosion or foreign matter is clearly
visible.

The use of any sort of abrasive may result in the removal of
the plating from the battery contacts. Once the plating is
gone, the pot metal underneath does a Very poor job of
conducting. The only fix is to put a layer of solder on the
pot metal, and gently file It down to a flat surface.

Cleaning terminals that don't show significant crud can be
performed with an electronics cleaner or alcohol and a
cotton swab or rag, or perhaps the eraser of a #2 pencil,
which does have a light abrasive quality to it, but would
take serious effort to remove the plating.

--
Mark
Click to expand...
 
Well, guys,

It appears, after a 36hr charge, operate, recharge, operate session, that
the unit is as good as new.

I never would have thought that a corroded/dirty contact would have been the
cause, what with years and years of good service from all sorts of radios
with rechargable power supplies.

The toothbrush was very, very soft, btw, :)

Live and learn.

Thanks for all the help.
 
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