MODULE Replacement CMU
1100.4903.82 3.38 E-4
Replacing the REFERENCE BOARD
(see chapter 5, spare part list, Current No. 540 and explosion drawing 1100.0008.01 D sheet 2)
The REFERENCE BOARD is installed at the front right top of the CMU as plug-in module in the cage.
For replacement proceed as follows:
Opening the instrument and removing the REFERENCE BOARD
½ Switch off the instrument, pull the mains plug and unscrew the rear-panel feet.
½ Place the instrument onto the front carrying handles, push the tube upwards and take off.
½ Unscrew the combi screw from the locking bracket of the module in the vicinity of the instrument fan
and fold up.
½ Pull off all MMCX plug-in cables (using a pull-out tool
∗
) from the top of the REFERENCE BOARD and
pull out the module towards the top with the help of the locking bracket.
Installing the new REFERENCE BOARD and completing the instrument
½ Insert the new REFERENCE BOARD in the instrument in the reverse order and connect all MMCX
plug-in cables.
½ Perform manual adjustment +5 VDC reference voltage and TCXO adjustment as described in
chapter 2.
½ Complete the instrument without causing damage to the cables.
½ Connect the instrument to the mains and switch on.
Automatic module data adjustment
½ During startup observe the display.
½ When three BEEPs can be heard, press the MENU SELECT key.
The version manager is started (see also chapter 4, Firmware update). The display includes the
menu item FIRMWARE UPDATE AFTER BOARD CHANGE.
½ Press the softkey to the left of the above mentioned menu item.
The automatic module data adjustment is performed under software control, firmware updates for
microprocessors and programmable devices being performed as well. This may take a few minutes.
After the adjustment has been terminated, the operating software starts automatically and the CMU is
ready for use and complies with the specifications.
∗
available in CMU-Service Kit CMU-Z3 (1100.7690.02)