Troubleshooting
Call-in Sensitivity (RP2) Adjustment (#74)
Summary: This test will prevent any new system activity from being initiated but will not interfere with
calls and functions already in progress.
Step 1. Dial
#74
from the display phone, then enter the physical number of the Speaker
Control
board line to be tested and keep the phone off-hook.
Step 2. Place a 1.5K ohm resistor across the T and G terminals of the line under test.
Step 3.
Step 4.
Ground pin 66 of the A Connector on the back of the MIO.
Monitor the test phone receiver for a clear tone while adjusting RP2 (located at the front of
the MI0 near the CPU flat-cable) in the following manner:
Slowly turn RP2 counter-clockwise until the tone becomes scratchy.
Slowly turn RP2 clockwise until the tone just becomes clear again.
Step 5. Mark the position of RP2 and repeat Step 4 from the clockwise end of the adjustment range
and, again, mark the position of RP2.
Step 6.
Step 7.
Center RP2 between the two marks.
While monitoring the test phone receiver, remove the resistor installed in Step 2 and verily
the tone goes away. If it doesn’t, the resistor may be on the wrong terminal. If so, repeat the
entire procedure, starting at Step 2.
