DIYbanter - View Single Post - Bearcat BC855XLT Looses it's Memory Occasionally

Fred McKenzie

In article ,
wrote:

Hi,

My Bearcat BC855XLT looses it's memory once in a great
while. Note: I am a service technician.

I did NOT find (Google search) a schematic for this scanner.

This scanner has a "unique capacitor type memory back-up".

I would like to modify this scanner and use a battery back-up because
it is a HASSLE to reprogram the 50 channels.

Does anyone know where I can find (willing to buy it) schematic?

Or.....

Does anyone know where I can find the modification I want to make
to maintain memory?

John-

I have a Radio Shack HTX-10 transceiver with that problem. When
disconnected from any power source, memory contents were maintained by
the charge on a 220 Microfarad capacitor. Over a month, memory contents
were lost due to leakage.

I installed a 3.6 Volt Lithium battery, isolated by a 1N4004 diode,
across the capacitor. This approach may work for you if the operating
memory voltage is higher than 3.6 Volts.

Last time I checked, memory contents were still good after ten years!

Fred