[MR2] MkI readio security code

[Kurt Krueger]

-------------- Original message ----------------------
From: STEVEN M HAUSHERR <hausherrs at sbcglobal.net>
>
Do you have access to a battery charger? Loosen the cables and hook up the 
battery charger then swap batteries. Car never loses power.

Might work, but a lot of battery chargers don't deliver anything that
would be considered good DC.  Generally a pulsating DC that goes from
zero to 20v without a load.  Electronics that run off DC don't generally
like that.

> OR I have never 
> tried thtis but start the car and then swap batteries 

That would likely be disastrous. Car alternators can generate well
over 100v and without the battery as a filter component you run the
risk of destruction.  Batteries do far more than most folks
realize in keeping the voltage spikes
under control.  Regulators are supposed to keep things under control
but they don't react instantaneously.  Batteries do.

(Turn off anything that 
uses power, radio, AC, etc). You could also use jumper cables to jump from 
> another car while swapping. 
>  
I used the battery charger trick on my 350Z because I didnt want to reset all 
the audio settings on my Alpine head unit. It was a PITA to get it to sound 
> right...

Glad it worked.  In your case the Alpine radio probably had some good
filter capacitors on the input.  Most radios do, but some are much
better than others.  Without good filters on the input, that pulsating
DC can do all sorts of strange things, like scramble the very settings
you're trying to preserve.

I like the newer radios.  They use flash memory to preserve settings
rather than a keep alive power lead.  So changing batteries won't
be a problem.  Trouble is that the security code IS in flash memory.