Re: Replace keyboard for piano accordion

hmmmmmmm i'm thinking if we put the battery force intermittently
while monitoring the temp of the pivot rod we might be able
to heat it enough for the purpose without tragedy to any
more Galanti's or others... (side note, Galanti is one of
the few companies still in business and still in the Famiglia...
they ceased accordion production decades ago, however, but are
still in the Music biz (one of the more successful Italian firms)

wonder if using a weller type heavy duty solder gun
and wiring the rod in place of the copper tip would be
enough power?

problem is, the pivot rod is not a resistance element,
just a plain piece of steel, and so to heat it we need to
force more current down it's throat than it can naturally
handle... and unless you get a darn good connection on
the far end the likely weakest point in the chain
will be your alligator clips or knife edge or whatever,
since the far end of the rod is not easily accessible.

i recall seeing the type of single cell tester/shunt
you mention, DoN, i have a different type in my kit
quite a bit newer design. coule still pry off two cap
plates until recently and test individual cells on many
types of batteries... my full tester has a lever
that puts a load for a time across the whole battery,
and it get's quite warm after performing a test

Ciao

Ventura

DoN. Nichols wrote:
According to ike milligan <accordiondoc@xxxxxxxxxxxxxx>:

I think using a car battery on it would require a load in series. Someone suggested buying a "Toaster", a kind of battery tester that has a thermo guage on it for a load.

DoN. Nichols wrote:
If that is what I am thinking of, that was designed for older
style auto batteries which had tar melted over the terminal jumpers
between cells. It had sharp points which you dug through the tar into
the lead bar jumpers to measure one cell's condition at a time -- that
is, it was designed for two volts maximum, not the 12-14 volts of
current automobile batteries. So -- you might need six of these in
series as a current limiter. And depending on where you find them, they
will either be junk (and priced as such) or antiques (and priced as
such). I doubt that you can find any *new* these days.

The appearance of them was a wooden handle, two metal straps
which bridged the meter, bent out a bit, and bridged the shunt element
(which was bent back and forth sort of like a sine wave. The two arms
continue on down, and end in sharp points to penetrate the tar and dig
into the lead.

They also have been exposed to a lot of battery acid in their
lives, so they will probably be pretty ugly. :-)


Another person suggested an old car starter motor.


That probably would not give you enough current, unless you also
had a car engine for it to crank.


I once tried it with no load and smoked an old Galanti keyboard (mine of course).


Ouch! That is not nice to have happen. What you need is a
series resistor to limit current, not exactly a load.

You *could* probably do it with a length of heavy gauge wire. I
suspect that something along the lines of a 2-0 wire (a fairly heavy
gauge), and perhaps a much as twenty-four feet or so.

Nope -- some calculations show that we would need a *lot* more
than that. I presume that the intention is to heat the rod to loosen
various things. Perhaps 100 Amps would be reasonable for that, and to
get that kind of current from a 12V (really 14V when fully charged)
automotive battery, you would need a resistance of 0.14 Ohms, and that
resistor needs to be able to handle 1400 Watts -- at least short term.
That works out to about 1000 feet of #2 gauge copper wire. Not cheap at
all. That is 200 pounds of copper, not counting the weight of the
insulation. And #2 wire is just marginal on carrying this much current.

I think that the better choice for this would be to find someone
with an old "buzz-box" welder -- or a nice new TIG unit, which can be
set to limit current to 100 Amps into a short circuit.

No -- I don't have one (yet -- though someday, I hope), so even
though we are in sort of the same area, you'll have to find someone
else for that.

Best of luck,
DoN.
.

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