Exchange Of Potentiometer; Work Steps - Siemens MAMMOMAT 300 Parts Replacement

Procedure - Potentiometer R863
Fig. 1

Exchange of Potentiometer

This part of the instruction describes the exchange of potentiometer R863, the position
transducer of the compression unit. Defects on the cord (cord torn, or similar) are
considered reason enough to exchange the whole compression unit. Allen keys of 2, 2.5,
3 and 4 mm with ball-shaped heads are needed, one Allen key sized 1.3 mm is supplied
with the repair kit to fit the securing radial grub screw of the (Teflon) pulley. The
compression unit does not necessarily need to be removed from the MAMMOMAT for this
repair.
However, the plastic covers of the tube assembly and of the carrier arm have to be
removed. Within the arm, right to the compression unit, the Connector X874 can be found.
This connector has to be disconnected when measuring the resistance value of the
potentiometer R 863. If it remains connected distorted values will be measured.

Work steps

•
Remove tube arm covers, locate the connector X874 within the vertical arm to the right
from compression unit, carefully interrupt this connection with the help of a small
screwdriver.
•
Drive slide manually into a middle position; remove lower cover by pulling the locking pin.
•
Remove the lid of the knob of the potentiometer for F-max with the help of a sharp object
(e.g. knife), remove rotary knob by unscrewing internal screw. Remove upper cover by
pulling the locking pin.
•
Mark and then remove the left and right side cover after unscrewing 4 screws on each
cover ( Note the difference of thread size; 2 x 2 x M4 on the top slab, 2 x 2 x M3 on the
bottom slab).
•
Remove curtain / filmstrip from the top of the slide by unscrewing the two hex socket
head (Allen) screws holding the little plate (1/Fig. 1).
Siemens AG
Medical Solutions
1
Fig. 2
SPB7-230.841.03
Rev. 02 04.04
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Page 1 of 6 M300/1000/3000/3000 Nova
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