Display data receiver adjustment procedure for CRM-IV

This procedure describes the adjustment of the data receiver in the CTLI (CRM-IV TouchLine Interface board), item number AC. The relevant stations are:

• 1007006100 CRM-IV Main modul with standard mic.
• 1007006101 CRM_IV Main modul with gooseneck mic.
• 1007006201 MCS, Multi Conference Station.

Necessary equipment to preform the adjustment:

Oscilloscope with 10M ohm probe with a insulating transformer on the power supply.<br\> An AlphaCom exchange.<br\>A screwdriver suitable for the potmeter's RP1 and PR2.<br\>Connect the oscilloscape probe to pin 11 on U3 (this is the PLL, the 74HCT4046), and the oscilloscope ground to the B-wire close to the station (not more than 3 meters). Set the scope to 1 Volt/line vertical division and 2 usec/line horizontal divisjon. Adjust RP1 and RP2 until the waveform it is as shown on the figure, be accurate! Disconnect the board and reconnect after 2-3 seconds. Dial 789 (the AlphaCom will initialise automatically after a while but the 789 will work as well).<br\>The display should now reset.