Repairing the faulty keypad of an HP 32sII
Takayuki HOSODA
Feb. 13. 2008

Japanese Japanese edition is here.
Open the hp32sII Blow the dust on and around the micro-
processor PCB by the canned air
Unmount the micro-processor PCB
and make it clean by the precision
electronics cleaner
Clean the LCD rubber(zebra) connector
and the contact of the film connecotor of
the membrane keypad very carefully
hp32sII-0.jpg hp32sII-1.jpg hp32sII-2.jpg hp32sII-3.jpg
Uncover the deformed foam rubber,
the main cause of the faulty keypad,
under the film connector
Apply the double coated polyethylene
foam tape with 0.8mm thickness
(3M 4462W) at 2.5mm width
Set the film connector, blow air again,
then remount the PCB
Apply the aluminum foil adhesive tape on
the back of the cover to reduce the dust
that is collected by the static charge
which may cause the contaminations
hp32sII-4.jpg hp32sII-5.jpg hp32sII-6.jpg hp32sII-7.jpg

Power supply current (Ta=26°C) : Vbattery=4.51V(SR44×3), Irun≈1.0mA, Iidle≈120μA, ISB<0.1μA
Low battery indicator turns on when Vbattery < 3.5V
Self-diagnostic test ([C]+[1/χ]) kept running without errors even if the Vbattery decreased to the voltage of 1.9V that you can hardly read the LCD.

HP 42S memory upgrade and overclock
APPENDIX - Program library
Inside the HP-32SII [Mail] © 2000 Takayuki HOSODA.
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