THOMSON VK231PS, Technical Manual

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74
GENERATION OF CAPSTAN MOTOR V
A 5 Vpp PWM signal is present on Output 99 of IT001. After integration by RT006, CT003, and
RT005, CT004, this signal is sent to the capstan motor control circuit. In this circuit, it is
compared to the reference voltage from Output 42 of IT001.
Capstan motor V at 9 of BT001, for all functions, is in the region of 2.6 V.
Output 98 of IT001 supplies a 2.5 Vpp PWM signal with a period of 48 µs. After integration by
RT004, CT002, this signal limits the current in the capstan motor. The voltage obtained after
integration is in the region of 2.4 V. During the FAST REW/FWD and SEARCH X7/X9
functions, this voltage becomes 2 V. Because of this, the current limitation is reduced.
42
98
99
IT001
RT005 /006
CT003 /004
RT004
CT002
REFERENCE:2,4V
T = 24 s
T = 48 s
0
5V
2,5V
0
VM
CAPSTAN
MOTOR
CIRCUIT
53
FWD:0V / REV:5V
LIMITOR
BT001
6
9
8
7
1
28
TT005
TT006
VMC
DW087
20VE
14 VE
H: FF / Rewind
Search : x7 / x9
L : (PB / REC)
Search : x3 / x5
12,6 VE CM