TM 11-6625-3053-14
ITEM
MALFUNCTION
CHECKS/CORRECTIVE ACTION
8
2. A2T1 input check.
(cont'd)
a) Continuing with multimeter, set to 100 VAC range. Measure
voltage at points listed below.
1) Ground to Collector of Q4 and Q2.
Voltage should measure approx 21 VAC.
2) Ground to Collector of Q3 and Q1.
Voltage should measure approx 21 VAC.
If these voltages are not obtained, go to check 3 below.
b) Continuing with multimeter, set to 100 VDC range. Measure
voltage between ground and the junction of C1 and C2 of the A2
assy at R5, on the white- orange wire (FO-2 Sheet 2 of 3)
Voltage should be approx +26 VDC.
If this voltage is not obtained, go to check 4 below.
c) If the correct voltages were obtained in checks 2a) and 2b)
above, replace A2T1.
3. A2 input check at Al card output.
a) Using multimeter set to 10 DC range, measure voltage between
chassis ground and point between R6 and pin 2 of P3 on the A1
card assy.
Voltage should be approx .7 VDC.
Square Wave at same test point when viewed on scope will be 1
V peak at approx 20 kHz.
If either of these is not obtained, go to T/S item 13, check 1.
b) Repeat voltage measurement between chassis ground and point
between R7 and pin 1 of P3 on the A1 card assy.
Voltage should be approx .7 VDC.
When viewed on scope set as in check 3a above, the waveform
will be the same.
If either of these is not obtained, go to T/S item 13, check 2.
4. A2T1 Centertap voltage check.
a) Using the multimeter set to the 100 VDC range, measure the
voltage between chassis ground and pin 1 of AR4 on the A1card
assy.
6-59