Bearcat BC855XLT Loosing Memory
Brad
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
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> 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
Brad
I looked inside, but I didn't see a "unique" capacitor. All capacitors
looked like conventional types.
Also, this scanner is holding memory. I can unplug the power
source, then later plug it in and the memory is still there. I asked
the customer if this loss of memory occurred around the time of a
storm. He said "no".
Brad
On Mon, 15 Sep 2008 13:08:01 GMT, in sci.electronics.repair you 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.
>
PanHandler
Ken Layton
no power.
Jeroni Paul
> 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
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
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Please remove one 'i' from my address when replying by email.
Stacey Chuffo
"Brad" <bpe...@verizon.net> wrote in message
news:48ce5c91...@news.verizon.net...
> 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.
>
I would hope the capacitor would be located inside the radio, where else
would the motherfucker be?
What makes you think that it's the capacitor? It could be the resistor
connected in series with the motherfucker or the memory chip itself going
bad.
Brad
Thanks to everyone for your help.
Obviously, "Stacey" is a juvenile.
This scanner has been working just fine in my shop, so I returned it
to my customer.
Brad
On Tue, 16 Sep 2008 13:31:20 GMT, in sci.electronics.repair you wrote:
>Hi,
>
> I looked inside, but I didn't see a "unique" capacitor. All capacitors
>looked like conventional types.
>
> Also, this scanner is holding memory. I can unplug the power
>source, then later plug it in and the memory is still there. I asked
>the customer if this loss of memory occurred around the time of a
>storm. He said "no".
>
> Brad
>
>
>On Mon, 15 Sep 2008 13:08:01 GMT, in sci.electronics.repair you 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.
>>