Archive of the former Yahoo!Groups mailing list: Korg Poly800/EX800 Users

Hi friends,

Well, it seems that I may have run into a slight problem with the
backup battery in the HAWK-800 kit. I don't think it's big enough to
do the job since my EX800 had lost its patches (twice) after replacing
the CR2032 battery about 6 weeks apart.

6 weeks is not very good now is it!

So, I had a look at the design and think I might have missed a pull
down resistor that would reduce the current by about half. I've added
the pull down onto both of the HAWK-800 kits and I guess in about six
weeks I'll know if it made any difference at all.

And then perhaps at some point after that, I'll have an idea as to how
much longer the little CR2032 battery will hold up those two 8K static
RAMs.

My calculations for using the CR2032 are below: I would appreciate
feedback from anyone if they can suggest if I've messed up these
calculations.

A high quality CR2032 battery gives about 230mAh or 230,000uAh.

A single 6264 static RAM in standby mode uses between 2 and 50uA.

So two static RAMs will pull between 4 and 100uA.

Therefore, the range of the battery life at 4uA pull should be 2,395
days or 6.5 years (I think this might exceed its shelf life).

At 100uA the life should be 95 days or a little over 3 months.

If we take the middle ground then at 50uA the life should be 191 days
or about 6.5 months.

Now, no matter how I look at it, this just doesn't look very good.

The longer term solution is now being looked at. There are two ways to
go about this. One way would be to use a rechargeable battery
scenario. The other, would be to write patches into flash memory. I'll
post again as soon as I come up with a solution.

In the meantime, BACKUP YOUR PATCHES, and do let me know how long your
patches last before you have to replace the CR2032.

Mike.