I Protection L/Rch; Tmp Protection L/Rch - Yamaha A-S700 Service Manual

c. I protection L/Rch
Cause: Excess current flow into ampli-
fier.
Speaker terminal shorted. (*)
Normal value: LOW (0V)
Detection port: PRI (80 pin of microprocessor
IC602 of FUNCTION P.C.B.)
Detected at: PRI (Amplifier output L/Rch of
MAIN P.C.B.)
* If the protection function works due to
shortage at the speaker terminal, the pow-
er turns off at the excess current protection
L/Rch. However, pressing the "POWER"
switch for OFF/ON causes following opera-
tion to take place and the power to turn on.
1. All INPUT indicators flash until the power
is turned on.
2. The VOLUME knob rotates counterclock-
wise automatically and stops at the 0
(MIN.) position.
3. The power turns on after some seconds.
d. TMP protection L/Rch
Cause: Abnormal temperature of heat
sink.
Normal value: 0 to 1.74V
Detection port: THML (92 pin of microproces-
sor IC602 of FUNCTION P.C.B.)
THMR (93 pin of microproces-
sor IC602 of FUNCTION P.C.B.)
Detected at: PRDL (Heat sink Lch tempera-
ture detection IC101 of MAIN
P.C.B.)
PRDR (Heat sink Rch tempera-
ture detection IC202 of MAIN
P.C.B.)
A-S700
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