Radio Shack TRS-80 Service Manual page 129

P20 J1
r'Yn"-
L1
3.3~h
J1 P21
r..-"""'"
I -
l..y.L.,.
P20
Ql
TIP 110
CRl
1N4002
Rll
1,1/2W
~--_-------14 2 MOTOR RTN
I---
RlO
lK
NOTES:
1. ALL RESISTORS ARE 1/4 WATT, 5%
UNLESS OTHERWISE SPECIF lED.
R8
470
A9
18
R 13
UK
, - V v v - - - / - - - - - - - - , 7 4 N MOTOR ON
~l
Q2
~
2N4124
R 12
2.2K
C2
1.0
~f-t----+
( ;;' - L' - --
~
+
R7
470
lK
C6
.47
10%
30V
R4 lK POT. AS
+
R6
43.2K
1%
C4
+
1.0
+
no~:
10%
80v
R3
lK
_ _ _ _ _ _ 10 _ _
1
9_ _ 8_
~ -
I
";K
l .
6
~~p.
:
f-
--.---4_''-1-_J-[~+/' ~
I
I Ul
+
I
'-
L~292!N_
_ _ _ _ _ _ _ _
_I
12 2 3 4 5
0---
'----..----+--.....-----'
+12V
1 10 f------------------.,....---___1~--'iI1l'-"T""--___1~-----_.,-------_/
3 3 + MOTOR PWR
' f
f,
GND
~
2
9
' -
~
R2
1M
RI
-TACH
4 2
20K
+ TACH
5 1
P21
Lv
2. ALL CAPACITORS ARE IN MICROFARADS
UNLESS OTHERWISE SPECIF lED.
NON-LINEAR SERVO BOARD
GND 2
9
A2
1M
Al
20K
-TACH
4 2
+TACH
S 1
P21·
P21
3 3 +MOTOR POWER
All
1,1/2W
4 2 MOTOR RETURN
R12
2.2K
AIO
IK
A13
2.2K
7 4 N MOTOR ON
Jl
P20
NOTES:
,. ALL RESISTORS ARE 1/4 WATT, 5%
UNLESS OTHERWISE SPECIF lED.
A9
470
I
I
I
I
I
I
·_1
8
L1
3.31lh
A7
470
AS
lK
Cl
47
C4
1.0
R4 lK POT.
A3
lK
J1
P20
2. ALL CAPACITORS ARE IN MICROFARADS
UNLESS OTHERWISE SPECIFIED.
LINEAR SERVO BOARD
FIGURE 19. SERVO BOARD SCHEMATIC
122