JVC UX-M55 Service Manual page 31

Pin No. Symbol I/O
18 SEB I RFRP output circuit switching terminal
19 VRO O Reference signal (VRO) output terminal
20 RFRP O Track count signal output terminal
21 BTC I Time constant adjustment terminal for bottom detection
22 RFCT O RFRP signal center level output terminal
23 PKC I Time constant adjustment terminal for peak detection
24 RFRPIN I Input terminal for track count signal output amplifier
25 RFGO O Output terminal for RF signal amplitude adjustment amplifier
26 GVSW I Amplifier (AGC, FE, TE) gain switching terminal
27 AGCIN I Input terminal for RF signal amplitude adjustment amplifier
28 RFO O Output terminal RF signal amplifier
29 GND - Ground terminal
30 RFN2 I Input terminal for RF signal amplifier
NJM7812A (IC302) : Regulator
1. Terminal layout
1.INPUT
2.OUTPUT (+12V)
3.GND
1 2 3
SEL level Bottom detection
GND ON
Vcc OFF
GVSW Mode
GND CD-RW
Hiz Normal
Vcc Normal
2. Block diagram
1
INPUT
THERMAL SHUTDOWN
BANDGAP REFERENCE
Function
Peak detection
ON
ON
OVER VOLTAGE PROTECTION
SOA PROTECTION
SHORT CIRCUIT
PROTECTION
3
GND
UX-M55
Q1
2 OUTPUT
R1
R2
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