Welch Allyn Micro Tymp 1, Service Manual

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Section 3.1 Service
M I C R O T Y M P 1 T R O U B L E S H O O T I N G
5. Disassemble stand to step #4 (Removing boards from housing, page 6)
6. Pull out the flex from the 8 pin connector. With an ohm meter check the pins of the flex to be sure
none of the elements are damaged. To do this, put the common clip of your meter to C (see fig.
below). With the other clip check each pin (1-8) to be sure that they are ok. The resistance of any
element must not be greater than 22 ohms. The largest allowable difference of all elements on a
printer is 3 ohms (e.g. if pin 1 was min at 14.5 ohms and pin 6 was max at 17.9 ohms the difference
would be 3.4 ohms. This is defective). If all pins are ok, go to the next step.
Replace the printer head, remove the print switch (switch closest to the printer) by unsoldering the 2
pins on the bottom side of the board. Pull out the pins located on the side and top of the printer head
(see fig.).
Remove the smooth shaft by pulling the pin from the gear on the side of the printer. Also remove the
gear that the pin slides into and the flat gear to the back of it. With a pair of tweezers pull off the
gasket ring located on the end of the grooved shaft. Slide both shafts part way out allowing enough
room to remove the printer head. Remove the printer head from the shafts and replace with a new
head (see fig.).
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