Optical Instrument Prism

ARMY

TM 9-6650-235-13&P

MARINE CORPS

TM-08552A-13&P

NOTE

Later configurations do not include the

following item.

f. Optical Instrument Prism. The prism assembly

is designed to permit inspection of the bore at a right

angle to the tube centerline. The prism assembly

replaces the mirror assembly by unscrewing the knurled

nut of the illuminating head assembly, lifting out the

mirror assembly, inserting the prism assembly in place,

and screwing the knurled nut back on.

g. Blind Illuminating Head Assembly. The blind

illuminating head assembly is designed to permit viewing

PRISM ASSEMBLY

of blind holes or cavities such as mortar tubes. This

optical assembly allows the field of-view to pass straight

through when the inspection mirror (1) is removed, and

is designed primarily to permit inspection of the area

around the firing pin of blind bores like mortar tubes.

Seven miniature lamps are in parallel for 115-volt

operation of the blind illuminating head assembly. Seven

24-volt lamps may be used instead of the 115-volt lamps

for 24-volt operation.

BLIND ILLUMINATING HEAD ASSEMBLY

1-5