[sdiy] bit one

[harrybissell]

There are two paths to clean contacts...

1) Noble Metal Plating (Gold)

2) High Contact Force (Gas-tight connection)

Both of these are effective methods.  For instance... the AMP Diplomate sockets
have side wipe connectors on both sides of the pin, as well as a contact area
that
keeps the metal-to-metal contact so tight that gas cannot enter.  They are
excellent against
both vibration and corrosion... even the tin plate variety which I swear by.

Then there are the machine screw, gold plated sockets. These rely on the 'noble
metal'
plating to stop corrosion... where most if not all IC pins are tin-lead coated,
making that
method of stopping the corrosion iffy at best. They often feature such POOR
retention
capacity that chips can fall out due to vibration.

This is one case where "RETENTIVE" is actuallt a good thing :^P

Another factor in contacts is the current/voltage applied to them. Below a
certain value...
gold plating, or "gas tight" connections are a must.  Switches, relays etc
usually cannot
have "gas tight" connections so they rely on gold plating and wiping action to
stay clean.

Higher current connection may not suffer from tin plating... in some cases if
they are mated
or disconnected under load... they are preferred to gold plating which can be
instantly removed by a small arc.

Sometimes people are correct... a manufacturer's decision to use a certain
connector is strictly
cost dependant, and replacing them is a good idea....

other times its just "gilding the lily"....

(depends on the individual application)

H^) harry

Rude 66 wrote:

> well, it's not somtething i'd start doing to all my synths immediately, but
> if it's reasonably sure that's the problem..i'd do it. it's drying now from
> a good cleaning..;-)
>
> additional question: what do you replace? only the plastic bit with the pins
> that the connector slides onto? or the cable itself? the ones on the bit are
> all soldered to the board on one side.
>
> would this same dirty contact story also apply to socketed chips?
>
> ruud
>
> ----- Original Message -----
> From: "greg montalbano" <greg.montalbano at ucop.edu>
> To: <synth-diy at dropmix.xs4all.nl>
> Sent: Friday, February 06, 2004 9:17 PM
> Subject: Re: [sdiy] bit one
>
> > Agreed -- as has been mentioned here before, the next step up in vintage
> > synth maintenance is replacing sockets & connectors with machine-tooled,
> > gold-types.
> > But that IS the next step up;  some folks don't want to go that far
> > (and then there are some folks won't accept anything less than re-chipping
> > the entire board -- was just working on an Oberheim Two-Voice, and I'll
> > testify that 30 year old CMOS just ain't that reliable).
> >
> > Depends on what you're up for, how much you want to spend, and how much
> you
> > care for your beast.
> >
> > ~GMM
> >
> > At 11:50 AM 2/6/04 -0800, Scott wrote:
> > >Hi gang,
> > >
> > >I work in the customer service department for a test equipment
> > >manufacturer, and
> > >the term "Gold Pin Mod" is ubiquitous to everything that was produced up
> > >until a
> > >few years ago, when my department started forcing its hand.
> > >
> > >It has to do with tin connectors, particularly on but sometimes not
> > >limited to,
> > >the power supplies.  Invariably, as time progressed, the equipment would
> > >become
> > >unreliable, jumpy, -generally screwed up in other words - and the
> customer
> > >would
> > >send it in.  Automatically, we'd replace the pins in the power supply
> > >connectors
> > >with gold plated pins, and soon we just started doing it automatically to
> > >anything that was in warranty.  Worked like a charm in exactly 100% of
> the
> > >cases.
> > >  Putting in tin connectors only bought a bit of time, and we are of the
> > > philosphy
> > >that you don't clean anything - you replace (these are high dollar boxes
> > >to begin
> > >with).  I finally moved up to 'core' development teams, and I *never*
> > >would sign
> > >off on anything that didn't have gold plated connectors on the power
> supplies,
> > >BOM price be damned.
> > >
> > >Of course, these are service monitors that get a lot of field work in all
> > >kinds
> > >of environments, but all the same - if I had a tasty vintage synth like
> > >that, I'd
> > >raid Fort Knox and see if there wasn't some way to put in gold plated
> > >connectors.
> > >  Just a thought......
> > >
> > >Cheers,
> >