Re: DSA 602 acting up (power supply?)


greenboxmaven
 

Currency made from rag paper is very good for burnishing contacts so long as it is clean to begin with. It is abrasive enough to remove dirt and many oxides without harming the gold plating on high quality edge connectors. The paper can be sprayed with contact cleaner before use if the dirt is really heavy. The cause of poor connections is very often dust and airborne particles that have landed at the juncture of the flat surface and the spring connectors and been drawn in between the contacing surfaces and pulverized by vibration and temperature cycles. The paste formed levers the contact surfaces apart, and may burn into a residue if the voltage is sufficient. Often, simply pulling a board out and re-inserting it a few times will restore operation, but it is still important to clean the dirt deposits off. For the female part of the connector, find a piece of cardboard of appropriate thickness and fold the edge of the currency over it. I have had excellent results with these techniques for many years.

Bruce Gentry, KA2IVY

On 7/15/20 8:21 PM, stevenhorii wrote:
Years ago I had a service guy for our ultrasound machines show me a trick.
This was for cleaning contact fingers on printed circuit card edge
connectors (not on anything like delicate switch contacts). He would use a
dollar or other currency he had in his wallet and would pinch it around the
edge connector fingers and rub it back and forth a few times. Seemed to
work. Paper is fairly abrasive so it makes sense. Has anyone heard of this?
I have used the idea and never had a problem with rubbing off the plating.
I would not do this on the contacts in those Tek switches.

On Wed, Jul 15, 2020, 19:55 David C. Partridge <
@perdrix> wrote:

AFAIK the white one is the soft one Don't even think of using the hard
ones
on gold pads.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Martin
Sent: 15 July 2020 21:31
To: TekScopes@groups.io
Subject: Re: [TekScopes] DSA 602 acting up (power supply?)

Hi Tom,

thanks for the answer and all the details. Right now I have a big repair
job
to finish, an HP8645A with multiple faults. But I'm confident to finish in
a
week or so.

I guess I will recognize the "Hypcon", must be something special. What is
this "white Stadler-Mars eraser"? Is this the one with fiberglass, or the
usual rubber?

Summer holidays are approaching... I must motivate my boys to carry the
other DSA from the basement up in the lab, so I can take care of both of
them. Theres a firmware topic to be clarified, too....

cheers
Martin








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