AT&T MERLIN 1030 Installation Manual page 41

e) Then quickly alternate between intercom voice and
intercom ring the remainder of your links.
(e.i.) A Merlin system having a total of 84 links
Alternate between intercom voice and ring 24
times.
Depress recall 2 times.
Alternate between intercom voice and ring
60 times.
4) If a loss or low volume of intercom tone is heard during
any alternation, a defective line module, voice terminal
module or basic telephone module is present.
*Note: It is very important that the system is in use while
performing this test. If necessary tie up a few c.o.
lines on main console.
5) Once a defective line module, voice terminal module, or
basic telephone module is detected.
Power down control unit and remove all line modules,
a)
voice terminal modules, and basic telephone modules,
except the 1st line module (slot 7), and the voice
terminal module your testing voice terminal is
plugged into.
b)
Alternate between the intercom voice and ring
buttons (repeat steps 3b through 3e)
If a failure is detected, check for bent pins,
c)
replace the line module, or voice terminal module
until no failure is heard.
d)
If/when no failure is heard, power down and re-insert
one module at a time, repeating the test (steps 3b
through 3e) after each module is re-inserted. If a
failure is detected, the last module inserted is the
defective module.