Service manual

51
Table 3-9. Control Board Test Connector, A2J7
PIN NO. SIGNAL NAME Vdc WAVEFORM/CONDITIONS SOURCE
Digital-Circuits Bias & Reference Voltages
1 +5V 5.0 A2Q3 (emitter)
22 + 20V(5V UNREG) 20.0 with 120Hz & 45KHz ripple AlCR6, AlCR7
14 2.5V ref 2.50 A2U9 (OUT)
6 0.5V ref 0.50 A2R79,A2R80
Analog-Circuits Bias Voltages
2 +15V 15.0 A2U12 (OUT)
21 -15V -15.0 A2U4 (OUT )
Status Signals
17
CV
TTL Lo if in CV operation A2Q6C-7 (collector)
16
CC
TTL Lo if in CC operation A2Q6F-14 (collector)
13
OV
TTL Hi if not OVP shutdown A2U11D-11
11
DROPOUT
TTL Hi if ac mains okay A2U17D-11
12
OT
TTL Hi if not overtemp shutdown A2U11B-6
Control Signals
25 PWM OFF
1.7µs TTL pulses, 20KHz
U1A-5
26 PWM ON
1.7µs TTL pulses, 20KHz
U2B-6
18 Ip MONITOR 1V pk, ½ sawtooth, 20KHz A2CR26 (cathode)
(at full power only)
8
INHIBIT
TTL Hi if not remotely inhibited A2R185C, U19A-2
15
DOWN PROGRAM
1.2-3.0 while not down programming A2CR21, A2CR27
7 OVP PROGRAM 1/10 OVP (6033A) e.g.: 2Vdc if OVP set to full
1/30 OVP (6038A) voltage output A3R6 (wiper)
5
OV CLEAR
+5V inverted OV reset line A8U4-35
19
PCLR2
+5V if +5V bias OK A2Q60-9
Commons & Current-Monitor
4 COMMON 0.0 common return for all bias
voltages, status and control
signals
A2C20(-), A2R50
9 COMMON 0.0 common return for 2.5V ref and
0.5V ref
A2R83, A21-20
10 I-TEST
≈0.005 (6033A).
inboard-side monitoring res A1R27 &A1R28, A1T2
≈0.055 (6038A)
3 V-MON-BUF V-OUT/12 trimmed V-MON for readback A8U25-6