View source for Restoring 1220, 1225 and 1230 keypad

'''''See also →''' [[Rebuilding 1230 keypad using 3D printer]]''

==Description==

[[Image:Bounce(1).jpg|thumb|left|250px|(Pic1) "Bouncing" switch, the second trace is the signal coming out of a [[Schmitt trigger]].]]
[[Image:Bounce(2).jpg|thumb|right|250px|(Pic2) Registered presses being sent to the LA.]]
*The [[1220]], [[1225]] and [[1230]] have a keypad interface for controlling them. The switches are tactile switches with a small spring. Over time they start to become extremely "bouncy". This is due to a number of factors, some including corrosion and weakening springs. Over time this will lead to problems such as the keypad being less responsive and the analyzer registering multiple presses. 

Picture 1 shows what the keypad is registering.
<div style="clear: both"></div>
==Fix==
[[Image:Bounce(4).jpg|thumb|left|250px|(Pic3) Keypad switches]]
[[Image:Bounce(5).jpg|thumb|right|250px|(Pic4) Keypad switches]]
* '''WARNING!''' When taking the analyzer apart, users are at their own risk! The inside contains lethal voltages and precaution must be taken.
*The switches that the keypad uses are still being manufactured today. They are C&K D6L90F1LFS and the D6L90F2LFS, they are the exact same. The difference being the force required to push the buttons. One takes 1.3 Newtons and the other 2 Newtons (Pic3). The keypad has 26 of them. Replacing them with new ones will fix the excessive bouncing. When de-soldering the switches one has to be careful of burning the PCB and lifting pads because the traces are very small.

:→ [[Media:D6L90F1LFS.pdf|Datasheet for D6L90F1LFS and D6L90F2LFS ]]
<div style="clear: both"></div>

==Conclusion==
[[Image:Bounce(3).jpg|thumb|left|250px|(Pic5) Restored keypad.]] 
* It is not known how long this fix will last, but it makes the unit usable again. After the replacement the signal is now clean (Pic5).


[[Category:Instrument repair reports]]