Ta/Tb - Yamaha R-S300 Service Manual

R-S300

4-2. TA/TB

Temperature of the heatsink is detected.
TA: The voltage at 84 pin (THM_L) of the IC502 is displayed.
TB: Not for service.
Normal value: TA 10 to 85 (Reference voltage: 5.0 V=255)
* If TA becomes out of the normal value range, the protection function works to turn off the power.
4-3. KEY 0/KEY 1
Panel key is detected.
KEY 0: The voltage at 95 pin (KEY0) of the IC502 is displayed.
KEY 1: The voltage at 94 pin (KEY1) of the IC502 is displayed.
(Reference voltage: 5.0 V=255)
When the A/D conversion value of the panel key becomes out of the specified range, normal operation will not
be available.
In that case, check the constant of voltage dividing resistor, solder condition, etc. Refer to table.
* When "4-3. KEY 0/KEY 1" sub-menu is selected, keys become non-operable due to detection of the values of
all keys. However, it is possible to advance to the next sub-menu by turning the "INPUT" knob of this unit.
(Reference voltage: 5.0 V=255)
Display
0 – 11
12 – 32
33 – 54
55 – 79
80 – 107
108 – 134
135 – 156
157 – 255
26
T A : 0 4 5 T B : 0 0 0
K 0 : 2 5 5 K 1 : 2 5 5
K0
DIMMER (U, C, R, A, L models)
TP (G model)
FM MODE / INFO
MEMORY
CLEAR
–
SPEAKERS A
SPEAKERS B
Key off
KEY1
KEY0
Display K1
0 – 11 PRESET <
12 – 32 PRESET >
33 – 54 FM
55 – 79 AM
80 – 107 TUNING <<
108 – 134 TUNING >>
135 – 156 –
157 – 255 Key off