Teac C-1 - POWER MUTING CIRCUIT

AMPLIFIER SECTION
8. POWER MUTING CIRCUIT
When the power switch is turned on and off, muting is
effected in the playback output circuit, the meter circuit
and the recording amplifier in order to prevent click noises
and unnecessary meter deflection. The muting signal is
provided by a circuit on the power supply PCB (Fig. 11).
When the deck is powered up a charging current flows in
C929 through routes (1) and (2). Q916 turns on for about
2 seconds, during which C929 charging is completed. The
muting signal (high) is transmitted via route (3) during
this charging time.
When the power switch of the deck is turned off, the charge
in C929 is rapidly discharged via route (4), and the point
(A) falls to a low level. Thus, Q916 base current flows in
the route (5) and Q916 tums on, producing the muting
signal. The muting signal continues until the charge in
C928 and C927 has completely discharged.
POWER SUPPLY PCB
Lch,Reh PLAYBACK AMP QiII9
OSC PCB Q835{L ch), 0836 (R ch)
Leh, Rch REC AMP, 0308,0315
T-1322 Da36
Fig. 11 Power Mute Circuit