[TenTec] Paragon 2 Memory Battery Back-up

[LEE BAHR]

Jerry:

Thanks for the input.  This makes sense.  My concern is for a Paragon 2.  I 
don't have one yet but plan to buy one if/when I can find one to my liking. 
Maybe there is someone on here who actually did this.  I would suspect it 
has been done many times since the manual says the "cell" within the 
microprocessor chip will maintain memory and work for around 10 years. 
These cells must all be dead bye now.  I have never had a radio without a 
small outboard battery which could be slipped in and out of it's holder. 
For those radios I routinely change them after a few years of service.  That 
is easy and fast.  This idea of having an internal "cell" good for 10 years 
being built into a microprocessor mystifies me.  I can't imagine why this 
would be done.  I have not heard of anyone being annoyed by this, so there 
must be some remedy for the problem.

Lee, w0vt
Houston, Tx



>
> Without having done it, I suppose one would cut the 5.6 volt power to
> the processor chip pin 40, insert a schottky diode for minimal voltage
> drop, then hook up a 6 volt chargeable battery (charged from the
> unregulated 13 volts) through a plain silicon diode to that same pin 40.
> 4 NiCad cells should hold the micro for a long time, might not need to
> be chargeable, just a couple 3 volt Li Cells, like 2032 in series to
> make 6 volts. When power was on the battery diode would be reverse
> biased, when power was off the schottky diode would be reverse biased
> and the battery would keep the processor supplied with power. Likely it
> takes a lot more power to hold up the processor than the processor's
> memory alone. I can't tell from the schematic what the processor number
> is, it shows the same MC146803EP2 part on a 40 pin and a 16 pin package.
> What is it really (Paragon II)?
>
> 73, Jerry, K0CQ
>