MECHANICAL AND ELECTRICAL FAULT ISOLATION

TM 11-7025-210-23

4-8.

MECHANICAL AND ELECTRICAL FAULT ISOLATION

Printer malfunctions may occur because of faults in mechanical or electrical components. Mechanical faults are easier to

find, therefore check for mechanical problems before you check electrical components.

4-9.

MECHANICAL NOISE ISOLATION

If a mechanical malfunction causes an unusual noise or binding, you can isolate it to the right or left side of the printer as

follows:

Power off Slip left drive belt off left drive pulley

NOTE

With left drive belt off the drive pulley, the printer will run only 1 to

1-1/2 seconds, then stop. You may need to restart the motor several

times in quick succession to provide enough listening time to verify

on which side of the printer the noise is located.

If the noise or binding is still occurring, the malfunction must be in one of the following units:

Motor

Right jackshaft bearing

Linefeed clutch

VFU mechanism

If the noise or binding condition is not occurring while the motor runs, the malfunction must be in one of the following units:

Left idler pulleys

Print belt pulleys

Print belt

Ribbon drive

Using the information gained by this check, go to paragraphs 4-10 and 4-11. Use the troubleshooting data in those

paragraphs to further isolate the faulty unit.

4-10.

ELECTRICAL MALFUNCTION ISOLATION

If an electrical malfunction occurs, it will be indicated by the following:

Lighted ALARM indicator on control panel. (Will also light when various mechanical malfunctions occur.)

A blown fuse on the power control board (XPS) or the logic board (LOG) as shown in table 4-1.

Lighted status indicators on printed wiring boards. (See paragraph 4-11.)

4-5