Table 5-4. Troubleshooting Delaying Sweep Plug-In Type 74-13A

TM 9-6625-1753-14

Table 5-4. Troubleshooting Delaying Sweep Plug-In Type 74-13A - Continued

Malfunction

Probable cause

Corrective action

Malfunction

Probable cause

Corrective action

Erratic triggering or no triggering with

Defective automatic trigger circuit.

Check

Q8201

and

its

associated

No output from + GATE connector

Defective

delayed-sweep

gate

Check Q8106, Q8107 and their

AUTO-NORM switch at AUTO.

components; replace the defective

(delayed sweep).

multivibrator.

associated components; replace the

transistor or component (fig. 5-12).

defective transistor or component (fig.

5-11).

Does

not

trigger

when

the

Open capacitors C8205, C8203

Replace the defective capacitor.

Measure the voltages as shown on the

COUPLING switch is set to AC.

(normal sweep); capacitors C8105,

functional schematic to help isolate

C8103 (delayed sweep).

the defective component.

Does

not

trigger

when

the

Open

capacitor

C8203

(normal

Replace the defective capacitor.

No output from the SAW connector.

Defective

normal-sweep

gate

Check Q8206, Q8207 and their

COUPLING switch is set to ACF.

sweep), C8103 (delayed sweep).

multivibrator.

associated components; replace the

Insufficient horizontal deflection.

Defective stage in the horizontal

Check Q8301, Q8302, Q8303, Q8304,

defective transistor or component (fig.

deflection amplifier.

Q8305, Q8306, Q8307, Q8308, Q8309,

5-11).

and Q8311 and their associated

Defective disconnect diode.

Check CR8205, CR8209, CR8211,

components; replace the defective

CR8216; replace the defective diode.

transistor or component (figs. 5-11 and

Defective Miller integrator.

Check V8203, V8204 and their

5-13).

associated components; replace the

Measure the voltages as shown on the

defective tube or component (fig. 5-

functional schematic to help isolate the

12).

defective stage.

Defective turn-off emitter follower.

Check Q8208 and its associated

Sweep rate calibration incorrect at

Defective resistor or capacitor in the

Replace the defective resistor or capacitor.

components; replace the defective

one position of the TIME/DIV

RC timing circuit.

transistor or component (fig. 5-11).

switch.

Measure the voltages as shown on the

Sweeps are not linear.

Defective Miller integrator.

Check V8203, V8204 (normal sweep) and

functional schematic to help isolate

their associated components; replace

the defective stage.

the defective tube or component. Check

Beam position indicators don't function.

Defective beam position lamps.

Check DS8302, DS8301 and replace

V8103, V8104, (delayed sweep) and

the defective lamps.

their associated components; replace

Defective horizontal deflection amplifier.

Check Q8301, Q8302, Q8303, Q8304,

the defective tube or component (fig. 5-

Q8305, Q8306, Q8307, Q8308,

12).

Q8309 Q8311 and their associated

Measure the voltage as shown on the

components; replace the defective

functional schematic to help isolate the

transistors or defective component

defective component.

(figs. 5-11 and 5-13).

Sweep is unstable at certain positions

Defective lockout circuit.

Check capacitors C8559 and C8558;

Measure the voltages as shown on the

of the TIME/DIV SWITCH.

replace the defective capacitors.

functional schematic to help isolate the

Sweep is unstable at all positions of

Defective lockout circuit.

Check Q8208, capacitor C8563, and

defective stage.

the TIME/DIV switch.

diodes CR8207, CR8206; replace the

defective transistor, capacitor, or diode

(fig. 5-11).

Sweep retrace is visible.

Defective lockout circuit.

Check Q8208, capacitor C8563, and

diodes CR8207, CR8206; replace the

defective transistor, capacitor, or diode

(fig. 5-11).

No output from + GATE connector

Defective

normal-sweep

gate

Check Q8206, Q8207 and their associated

(normal sweep).

multivibrator.

components; replace the defective

component (fig. 5-11).

Measure the voltages as shown on the

functional schematic to help isolate the

defective component.

5-8