Section II. PREOPERATIONAL PROCEDURES

TM 11-405-10

Figure 20. Interval Timer FN-5(1), front view.

Section II. PREOPERATIONAL PROCEDURES

Note. Always clean the lenses before

17. Changing Lenses

placing them in the equipment (par.

a. General. If the negatives to be enlarged are 35-

mm or larger, but less than 21/4 inches square , use the

b. Changing Condenser Lens Assembly.

31/2-inch condenser lens assembly square, use the

(1) PH-129-(*) or PH-639(*)/TF.

3/2-inch condenser lens assembly and the 2-inch

(a) Pull the control lever (fig.

projection lens. If the negatives are larger than 21/

forward and over the control lever

inches square, use the 61/2inch condenser lense

stop.

assembly and the appropriate projection lens listed

(b) Loosen the knurled screws (fig. 2)

below.

on the base of the lamp house.

(1) PH-129-(*) or PH-639/TF, 51/-inch

projection lens

(2) PH-639A/TF or EN-16(1), 5:

1/8-inch

projection lens.

ACO 5894A