Temperature Circuit.

TM 55-4920-411-13&P

4-10. Temperature Circuit.

Table 4-8. Temperature Check

a. Performance Check.

(1) Position controls as listed below:

(a) POWER SWITCH to OFF.

(b) FUNCTION SWITCH to 0%.

(d) TEMP SWITCH to NORM.

(2) Connect test set to autotransformer, using

power cable supplied with unit and connect autotrans-

NOTE

former to a 115-V ac power source and adjust for 115-V

output.

If test set will not adjust on both 400 and

800 settings, try adjusting R32 (fig 4-4 in-

(3) Set POWER SWITCH to ON and allow at least

stead of R40. Adjusting R32 changes am-

15 minutes for warmup

bient readings. Take a new ambient read-

(4) Connect differential voltmeter to SIGNAL

ing before returning to para 4-10a.

OUTPUT (J2) pin E(+) and pin D(-), using two leads (B2).

b. Troubleshooting and Repair (Temperature Cir-

(5) Place probe end of thermometer adjacent to ter-

minals of J2. Wait 10 minutes for thermometer to sta-

cuit).

bilize.

(1) If output voltage is several volts high and unad-

justable, check TEMP OUTPUT potentiometer RI for

NOTE

continuity and broken or loose wires. R1 is a 2K lo-turn

Constantly check thermometer temper-

pot. Replace R1 (55, fig 4-12), if defective.

ature values to insure proper millivolt

(2) If there is no output voltage or output voltage

values.

cannot be adjusted, see Troubleshooting Table 4-3.

Check connector J2 for continuity between pins J and H

(6) Set TEMP OUTPUT control for 400C plus

and J and G with switch S3 in NORM position. Fig 4-5

value in degrees C as indicated on thermometer. If dif-

shows pin arrangement of J2.

ferential voltmeter indication is not between 16.14 and

16.65 mV dc, adjust R40 for 16.400 mV dc indication on

RESULT : Continuity shall be present.

differential voltmeter. If indication cannot be met, see

(3) If continuity is absent, open simulator and

table 4-3 and para b.

check switch S3 for continuity (fig 4-5). Switch action is

(7) Set TEMP OUTPUT control for 800C plus

NORM: 2-1, 5-6; LOP: 1-2, 4-5; HI OIL TEMP: 2-3, 5-6.

value in degrees C as indicated on thermometer. If dif-

Replace S3 if defective. Also replace seal (54, fig 4-12), if

ferential voltmeter indication is not between 33.031 and

worn or damaged.

33.523 mV dc, perform (a) and (b) below. If necessary, see

para b and table 4-3.

(4) If S3 checks good, check wiring between S3 and

J2. Check connector J2 for continuity between pins J

(a) Adjust R42 for 33.277 mV dc indication on dif-

and H and between J and G when switch S3 is held in

ferential voltmeter.

LOP position

(b) Repeat (6) and (7), as necessary for best in-

RESULT: Continuity present from J to H and ab-

tolerance compromise.

sent from J to G.

(8) Repeat techniques of (7) above at TEMP OUT-

(5) If result is not true, open simulator and check

PUT control settings listed in table 1-8. Differential

switch S3 for continuity. Replace S3 if defective.

voltmeter indications wil1 be within limits specified

4-23