Canvm ConpcREZITloN roBEL C-9 sERvlcE pmN[]EL
SHT4
3.0 uNlunsEL PRoCREtmES:
The follchring pracedures apply to all internal service cork on the C-9
unit regardless of which category the caplaint fits.
3.i Rernov'e the cover frcm the unit
3.2 Verify that the ac line voltage selector is set for the laical voltage
3.3 Verify that the prcper value line fuse is installed for that voltage
3.4 Apply EC line pouer to the unit
3.5 Set INIE[TION REIO and LIsrmunrs ARERE buttons Our; mneGRAM IN
The informtion re9a:£±r+2:62voLanTdc3#|oN« {sH=TION 7. 0 ) .
in the section entitled {L±ne Voltage & fuse) is found
4.o GENERAL motHESHocITnG:
These prceedures apply to the "dead" unit and/ar units which exhibit
severe hun, noise or distortion that is audible and/or units which function
intermittently in terms of passing a signal or exhibit a turnron thLxp.
4.i Double check the ac pchrer source and line fuse. Make sure the uhit
is plngged in.
4.2 Verify that the PCRE Ou IED is illuminated. If not, and step 4.3
is ccxpleted successfully, replace the IED er its series resistor.
4.3 ifeasure the bipolar in sixplies. A positive voltage of 12.8 plus or
minus 1.5 should appear at every I]C's pin #11 and a negative voltage
within the same limits should appear at every IC's pin #7.
4.4 If step 4.3 yields unacceptable results, troubleshoot and repair the
pchrer supply and/or lcx:ate the offending shorted caxponent{ a ).
4.5 If the sixply voltages are within linits and a gross malfunction per-
sists, try the following sngge§tions:
A. One channel dead.. .suspect bad solder connections and/or a short
or crack in the FCB or a nan-functioning IC section.
8. Gross hun on one ar both channels.. .check the pouer supplies for
excessive Zic ripple ccl[ponents {>50 millivolts}. If this is not
the cause, lock for apen ground connections.
C. Gross distortion an cme or both channels„ .can be caused by a
near short en the output of any IC section but is Irore likely to
be a bad re. Ifoving frern input to output while passing a 1 kHz
` test signal, lcok at each successive re output until the guilty
device is located.
4.6 If the unit functions praperly except for a loud ppp or thump upon
power-xp, suspect the turnman "te cirouitry. With a 2.5V lkHz
output signal present, poser the unit deem for 5 seconds. tftyon
turn-on, both outputs should be attenuated at least 20dB for about
one second. If both chapels fail this test, suspect the FRI drive
cirouitry surrounding IC3. IC3 pin 12 should exhibit a positive
slgnal txpn porter-tp, suddenly switching to a negative level after a
seecmd or tva. If the F" gate drive is correct, suspect the FH{s}.
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