whine from dying Ultralife lithium 9volts in a Lectro UM 400

"freeheel" wrote ...
> Batteries were new off the shelf ( no idea how fast their stock moves)
> Lectros are 2 months old. (most recent updates) Weather was mountain
> variable, rain, hail and bright sun) Altitude was 4500 to 6000 meters)

Seems possible that the cells were out-gassing at a
higher rate than normal at that significant altitude
(and associated lower barometric pressure.)
 >> Stay informed about: whine from dying Ultralife lithium 9volts in a Lectro UM 400 

Sorry, my mistake. 6000 feet, not meters! So not super high. Valley
bottoms of the Canadian Rockies.
Cheers,
Brent C
 >> Stay informed about: whine from dying Ultralife lithium 9volts in a Lectro UM 400 

Thanks for chiming in Larry. I'll confirm that I've only heard this
with Lithiums - the alkalines go quietly into that good night... My
main concern is that some kind of damage may occur if the power supply
is oscillating; It'd be great if you were able to duplicate it and let
us know what you think is happening.
Cheers
Brent C
 >> Stay informed about: whine from dying Ultralife lithium 9volts in a Lectro UM 400 

Hi John,
Well there is no switching power supply in the 195D's. After all, they
were built in the previous century. :-)

If the external input voltage is low enough, the 195 D regulator may
be giving up and just passing the power straight through, noise and
all. That doesn't explain the whine from failing intrnal batteries.
Best guess may be some audio circuit oscillating at lower than normal
voltage. Or, as mentioned, it's a forerunner of the battery banshee
circuit. We can check it, but you can buy a lot of batteries for a
repair charge.
Best Regards,
Larry Fisher
Lectrosonics



On Mon, 07 Aug 2006 22:06:42 -0400, "G. John Garrett, CAS"
<jg RemoveThis @soundcartREMOVE.com> wrote:

>I have the whine in my 195D -receivers-. One in particular, actually.
>When my NP1 starts going down sometimes I will hear it and switch to
>internal batteries and it goes away. Or if I'm on internals and it
>starts whining and I switch to ext power [with sufficent voltage] its
>fine agian. So there's that data point.....
>
>
>John
 >> Stay informed about: whine from dying Ultralife lithium 9volts in a Lectro UM 400