Bearcat BC855XLT Loosing Memory

[Brad]

Hi,

I have a Bearcat BC 855XLT scanner (scanning radio) in my service shop.
No schematic. The radio lost all it's memory, but I was able to reprogram
some of the channels and the radio works.

The OM says, "A unique capacitor type memory back-up eliminates the need
for batteries". I suspect that maybe this capacitor is going bad(?), but
since I don't have a schematic, I have no idea where this capacitor is
located.

Thanks in advance, Brad

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[Michael A. Terrell]

Brad wrote:

Hi,

I have a Bearcat BC 855XLT scanner (scanning radio) in my service shop.
No schematic. The radio lost all it's memory, but I was able to reprogram
some of the channels and the radio works.

The OM says, "A unique capacitor type memory back-up eliminates the need
for batteries". I suspect that maybe this capacitor is going bad(?), but
since I don't have a schematic, I have no idea where this capacitor is
located.

The is a type of RAM called CapStore. It was a common static RAM,
with some flash memory. It detected a power loss and stored the
contents in the flash memory, and on power up, wrote it back to the
static memory. We used it to replace the 2k * 8 battery backed RAM in
our products.

http://www.zmd.de/pdf/CapStore.pdf

<http://www.google.com/search?q=capstore+ram&rls=com.microsoft:en-us:IE-SearchBox&ie=UTF-8&oe=UTF-8&sourceid=ie7&rlz=1I7GGLD>


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[Ken Layton]

The manual states the memory backup is only good for up to 3 days with
no power.

 

[Jeroni Paul]

On 16 Set, 23:59, Ken Layton <KLayton...@aol.com> wrote:

The manual states the memory backup is only good for up to 3 days with
no power.

I have an old digital radio tuner with 8 presets. Its memory is kept
out of a standard 470uF capacitor, probably very low consumption SRAM
and lasts a few weeks.

 

[Franc Zabkar]

On Mon, 15 Sep 2008 13:08:01 GMT, bpetria@verizon.net (Brad) put
finger to keyboard and composed:

I have a Bearcat BC 855XLT scanner (scanning radio) in my service shop.
No schematic. The radio lost all it's memory, but I was able to reprogram
some of the channels and the radio works.

The OM says, "A unique capacitor type memory back-up eliminates the need
for batteries". I suspect that maybe this capacitor is going bad(?), but
since I don't have a schematic, I have no idea where this capacitor is
located.

There are some Uniden Bearcat service manuals here:
http://www.mods.dk/manual.php?brand=uniden

Your model's SM is not listed, but maybe a similar memory backup
scheme is used in other models. Be aware that the above site allows
only one free download in 4 days.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

 

[msg]

Michael A. Terrell wrote:

Brad wrote:

Hi,

I have a Bearcat BC 855XLT scanner (scanning radio) in my service shop.
No schematic. The radio lost all it's memory, but I was able to reprogram
some of the channels and the radio works.

The OM says, "A unique capacitor type memory back-up eliminates the need
for batteries". I suspect that maybe this capacitor is going bad(?), but
since I don't have a schematic, I have no idea where this capacitor is
located.



The is a type of RAM called CapStore. It was a common static RAM,
with some flash memory. It detected a power loss and stored the
contents in the flash memory, and on power up, wrote it back to the
static memory.

<snip>

If not this device, then perhaps you have static RAM with standby power
from a supercap (perhaps about 1F). Look for a squat round package which
looks a little like an electrolytic or a battery cell encased in plastic.
I have a scanner so equipped and have seen supercaps used in many
handheld and ruggedized devices where battery (cell) changeout would
be difficult.

Michael