29 Chapter 3 Maintenance
3.7 Membrane keypad
This eventually wears out after exhaustive and prolonged use. The metal
dome switches lose their elasticity, the contact surfaces wear down, and
chemical corrosion sets in. The membrane keypad film can become torn.
If more than, say, three metal domes are broken, this may indicate that the
keypad tail series is broken, or that the single cable connecting the keypad
tail is defective.
Replacing the membrane keypad is now easier than before. You must,
however, slide out the work drawer.
To replace the operating membrane keypad:
1. Switch off the power, and detach the main power cord.
2. Detach the work drawer and cover from the AWS-8248 unit. (See
Fig. 2-1.)
3. Slide the work drawer out as far as it will go.
4. Remove the membrane keypad connector protective bracket, and
carefully pull off the two membrane keypad cables.
(See Fig. 3-10.)
5. Tear the operating membrane keypad from the aluminium panel,
and replace it.
To replace the function membrane keypad:
1. Tear the function membrane keypad from the aluminium panel
directly.
2. Carefully pull off the membrane keypad cables connecting the key-
pad tail. (See Fig. 3-10.)
3. Remove the function membrane keypad, and replace it.