Re: hp41cv repair question Message #3 Posted by Randy on 12 Nov 2004, 11:16 p.m., in response to message #1 by Andy
Five to ten minutes is all you need in an ultrasonic cleaner.
ANY moisture inside the keyboard will cause problems. Four days should have been enough time though if you shook it out well afterwards and pressed all the keys to expell the water inside. If in doubt, the 41 service manual (on CD5 or the DVD) details the keyboard connections, I would ohm out the matrix to see if there is leakage anywhere.
Residual flux on the display connections will cause trouble as well, they need to be spotless. Clean with isopropyl alcohol or the proper flux remover for the type of solder used. Do not allow the flux remover to get into the keys or on the display window or you'll have intermittant keys and white haze on the lcd.
If your units logic board to keyboard interconnects are the early pink elastomeric strips, try exchanging them with the later gold metal type. They tend to be very problematic.
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