Thanks for the advice Karl; I'll give it a try.
Gary
toggle quoted message
Show quoted text
--- In hp_agilent_equipment@..., Karl Schmeer <shire03@...> 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 <GEMCCLUNG@...>
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]
