开云体育

----- Original Message -----
From: Gary
To: hp_agilent_equipment@...
Sent: Friday, January 18, 2013 8:50 PM
Subject: [hp_agilent_equipment] Re: Foam conductor problems



After taking these boards apart many times the results were always the same, either one or more LEDs and one or more buttons were not working. Every time it was a different set of buttons or LEDs. So I decided to take out the conductive foam and make my own mechanical connection using molex connectors and a right angle header. Now all the buttons and LEDs are working perfectly. Pictures of my mod are documented under "3561A repair"

Gary

--- In hp_agilent_equipment@..., "Gary" wrote:
>
> Thanks for the advice Karl; I'll give it a try.
>
> Gary
>
> --- In hp_agilent_equipment@..., Karl Schmeer wrote:
> >
> > Conductive foam:? I have found the torque on the mounting screws needs to be
> > near perfectly? equal for these to work. Lots of trial and error :-)
> >
> > As for the switch contacts, I have found it is a good idea to wash? with
> > distilled water? after the soaking in alcohol for a couple of hours, After this,
> > they need to dry overnight before re-installing. They will not work right away!
> > BTW recently I have found placing wet things on top of my de-humidifier, where
> > the really dry air comes out speeds up? the process.
> >
> > Best Luck
> >
> > Karl
> >
> >
> >
> > ________________________________
> > From: Gary
> > To: hp_agilent_equipment@...
> > Sent: Fri, December 28, 2012 10:19:59 PM
> > Subject: [hp_agilent_equipment] Foam conductor problems
> >
> > ?
> > I've added some pictures under "3561A repair" to document a problem with my SA.
> > All the electronics check out after replacing some parts but some of the buttons
> > and most of the LEDs were not working on the front panel. After opening the
> > front panel I found that this conductive foam seems to be the culprit. I've
> > repaired LCD displays by cleaning conductive foam but the conductors in this
> > foam seem very small. I cleaned it up with some ISO-alcohol and some of the LEDs
> > started working but some of the key pads quit working. I cleaned it a second
> > time and the same results. Some other buttons are working but some still not.
> > The LED problem is solely the problem of the conductive foam but the keys could
> > also be the conductive pads on the rubber keys. I've measured the resistance on
> > most of the pads and they are about 50 ohms except for some that are 200 ohms
> > and greater (up to about 480 ohms). I'm not sure what the max resistance can be
> > and still make the key function. My solution first is to just solder the two
> > boards with a connection harness to eliminate the conductive foam but I'm not
> > sure how to fix the rubber key problem. I have some conductive paint but the
> > resistance is still high, around 150 ohms. Does anyone have any success
> > repairing this kind of problem?
> >
> > Gary
> >
> >
> >
> >
> > [Non-text portions of this message have been removed]
> >
>





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