[sdiy] several questions

[harry]

Hi Elby: inline

Mountain Man wrote:

> A small spate of questions for y'all  :)
>
>  - I'm doing powersupply repairs on my Xpander.  I'm wondering if I
> should change the backup battery while I have the case open - given that
> the synth is about 15 years old.  The battery (a 3V panasonic lithium)
> looks in fine condition, and I read over 3 volts on the meter.  It would
> be a bit of a pain to replace, so if its not called for, I'd rather
> not.  Opinions?  If I do replace, are there special precautions I need
> to take to prevent losing data?

Lithium Batteries have an wonderful hidden "feature"... the depleted
sections of the battery turn into very good conductors... causing little
drop
for the remainder of the voltage. A meter will NOT tell you the charge
remaining... they will stay 3V until a swift and possibly untimely death.

If its easy to get at later, leave it. If not... replace it now.

>
>
> - I'd like to get some tips on quality of different manufacturer's
> components.  I'm ordering aluminum electrolytics.  I notice that
> nichicon components are at least twice the price of xicon, even though
> the specs seem similar.  Since the ones I'm replacing are nichicon, I'm
> spending the extra cents, but I wonder in general should I pay for
> higher priced components?  Is there a "comsumer reports" for electronic
> components?  :)

I just bought some xicon components. No troubles so far.  The trick is to
look up the part number of Nichicon (also a good brand...) and see if you
can figure
out WHY the original engineers of manufacturers specified it.

Sometimes its the cheapest part they could find... sometimes its LOW ESR.
High
Ripple Current, Tight tolerances, extended temperature range, etc.

USE the "harry" rule here.

"All previous engineers are either incredibly STUPID or their designs are so

advanced and elegant that I'm missing 90% of what I see before me."

Usually they turn out to be pretty smart...

>
>
> - I want to get some switches to put in-line on wall warts for units
> that have no switch of their own (a rocker switch, I guess).  I looked
> through my handy Mouser catalog, but didn't see any "standalone"
> switches (i.e., not for mounting).  Can someone point me to something
> good?

They make cord mounted switches for lamps (120V) in your hardware
store. They are cheap-o little thumbwheels... they could be made to work
if the cables are right... or if you solder them.

Better is to buy some power outlet strips with one master switch... I'm
getting
these for $2 at the local ACO Hardware...

H^) harry

>
>
> Thanks all,
> Elby