[sdiy] Future SYNTH-DIY

[Magnus Danielson]

From: "Paul Schreiber" <synth1 at airmail.net>
Subject: [sdiy] Future SYNTH-DIY
Date: Sun, 22 May 2005 14:09:56 -0500
Message-ID: <0bf301c55f01$d7f91b00$0201a8c0 at bilbo>

> Well, the directive certainly does NOT prevent folks from tinkering at home
> in the lab with older, lead-containing parts. So, every start saving $$$ and
> buy 200ea of all the 5% resistor values, 100ea of common parts (TL072,
> 1N4148, etc) and we can all be "DIY Hermits".

There will probably be a big price-dump as the target date closes in.

> Also, it does NOT effect older analog synths at all, AS LONG AS you can
> *prove* the date of manufacture (ie it has a sticker on it). Parts for
> *repair* (like CEM/SSM chips) are exempt.

Good.

> What it DOES 'prevent' is shipping the parts/assemblies across EU borders.
> Just to pick of Doepfer, his boards are stuff in someplace like Hungary and
> shipping them is a problem.

Ooops!

> Also, don't forget there are *3* things to worry about:
> 
> a) solder
> b) parts
> c) the pc board
> 
> Currently, pc boards that are designed for lead parts are "hot air leveled"
> with lead-tin solder. You *can't* tin-plate, because tin grows "whiskers".
> So, the pc board suppliers are going full-tilit-boogie on alternative plating
> materials.

You can gold-plate it. However, that's expensive and takes some attention. From
the top of my head, the process contains three major steps:

1) Dip the board into acid to "rug up" the copper foil surface so the nickel
   grabs the copper.
2) Put the nickel on.
3) Put the gold on.

Now, don't leave the boards in the acid too much, or they will fail the
electrical checkout. ;O)

Don't put too much gold on, since that will make the tin-gold mixture brittle
as the gold is almost completely dissolved into the tin/whatever. The effect in
lost strength is DRAMATIC. From taking heavy abuse (we superglued a bolt onto
the BGA and put 50 kgs of weigths on it and no problems) to being easy to knock
the big BGA off the board by acidentilly hitting it or having the box
transported isn't the best reliability we'd seen, but then breathing down the
neck of our suppliers that problem is gone.

> See this page for TONS of data, scary photos:
> http://nepp.nasa.gov/whisker/

When you see that, you start to apprechiate why there are a few exceptions to
ROHS, until we get things sorted, right? ;O)

> Also, if you do have a lead-free pc board and lead-free soldering, but have a
> leaded part, the lead contaminates the process and cracks form in the joints.
> 
> It a freakin' headache from any angle.

Indeed. This is why the consumer market has to take the worst of the bashing
(and hence there is a marketpull of a solution) before it hits the things we
*really* depend on.

> Paul S.
> back to lead soldering....yum

You do wash your hands afterwards, don't you? And yes, doing it professionally
you do take your Pb blood levels regularly? It is not a lauging matter I might
add.

Cheers,
Magnus