[TenTec] Paragon 2 Memory Battery Back-up Solved

[Dr. Gerald N. Johnson]

Digging deeper in the HOT attic, I found a Motorola Data Book with a 
section on the MC146805E2P. There is NO battery in that part. Digging 
deeper in the Paragon II manual, I found a board with a DS1220Y-200 
Nonvolatile Static RAM and a DS1287 Real Time Clock. THOSE ARE THE 
packages with batteries that can die with old age. I knew about the DS 
devices, I didn't know Motorola did the same and I don't think they did.

Anyway, googling DS1287 I found a page about replacing the battery with 
a link to another opinion about how to do it. 
http://www.walshcomptech.com/ps2/dallasrework.html That was on the first 
page of 8190 hits. The first 30 hits averaged 2 opinions per page on 
carving into the DS1287. It might also be replaced with a DS12887 its said.

As for the DS1220Y-200, its still a valid Maxim/Dallas part number, 
though Digi-Key hints the ROSH DS1220AD-200 would be more appropriate. 
Either is under $12 but they will order one of the AD but want an order 
for 56 minimum of the Y.

Thing that might prove useful is that Maxim will sell samples direct. 
Maxim (www.maxim-ic.com) recommends the AD part because the battery 
doesn't begin to age until its used where the Y part ages from the date 
of manufacture. They might send a free sample of the DS1220AD-200+ part 
which should fit fine or will sell it for $17.85 on their web page.

Appears to me that since the DS12887 and DS1220AD-200 are good 
Maxim/Dallas part numbers with NEW batteries, there isn't a significant 
problem. Might cost $35 from Maxim or one of their distributors if you 
can't get them to send you a sample. Most companies like to send samples 
to engineering students. I've not tried for specific samples from 
Maxim/Dallas, but I had more than an apple box full of similar samples 
from decades of samples arriving unsolicited that I've already moved. I 
need to get back to the moving, the computer hasn't moved yet but the 
attic and bedroom here are running about 90 degrees and the new place is 
so much more comfortable, I'm sleeping there now.

73, Jerry, K0CQ

On 5/30/2010 4:00 PM, LEE BAHR wrote:
> 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
>
>