E.F. Johnson Company 5100 Series Service Manual page 134

SW_VA5_0
C76 C77 C78 C88
4.7uF 4.7uF 0.01uF 0.01uF
GND
R77
3 TONE_SIG
100K
R83
C79 0.1uF
15 AUDIO_OUT_M
100K
R86
C80 0.1uF
15 AUDIO_OUT_P
100K
VA_REF2_5
5 VOL_LVL
R73
33K
6
L3 0.1uH
7
5
U17B
OPA4340
R79
75K
VA_REF2_5
R85
100K
15
C81 0.1uF
16
14
U17D
R88 OPA4340
100K
4
R91
3
100K
C84
0.01uF
GND
5500-420 USER INTERFACE BOARD VER C SCHEMATIC (PAGE 9 OF 18)
8-58
R78
100K
R246
3 MUTE_B
100K
R84 100K
R87
11
C82 1uF
10
100K
12
U17C
OPA4340
R89
100K R90
10K C139
GND
100pF
R244 GND
1
U18 10K
OPA340 C140
100pF
SW_VA5_0
GND
R92
SW_VA5_0
100K
R93 C12
100K 0.01uF
GND
Internal Speaker Amp
R272 0
2
VIN
4
DC/SD
7
BYPASS
3
HP_SENSE
Q10 C142 C83
100pF 0.1uF LM4865M
MMBT3904TT1
Do not place R268
R268 SW_VA5_0
56K
R245
220K
External Speaker Amp
GND
L4
0 R273
2
VIN
4
0.1uH
DC/SD
7
BYPASS
3
HP_SENSE
C141 C72 LM4865M
0.1uF
100pF Q8
MMBT3904TT1
GND
Q2
MMBT3904TT1
R94
10K
GND
R82 51K
GND
2
1
VA_REF2_5
3
U17A
OPA4340
SW_VA5_0
U8
5
INTSPKR_P1
VO1
8
INTSPKR_M1
VO2
1
VDD SW_VA5_0
6
GND
GND
U21
5
VO1 EXTSPKR_P 11
8
EXTSPKR_M 11
VO2
1
SW_VA5_0
VDD
6
GND GND
R247
nSEOP 7
100K
MUTE_A 3