TM 5-5420-226-20-1 DETAILED TROUBLESHOOTING PROCEDURE Symptom-72 SUPPORT SYSTEM -   PERISCOPES (Continued) Check   operation of  IR  periscope by  substituting it with a  serviceable unit. Second Technician (Operator’s Station) l Obtain and    install serviceable IR    periscope (TM 5-5420-226- 10). First Technician (Commander’s Station) l Connect IR    periscope power cable (CKT 517)    to   IR powerpack. Second Technician (Operator’s Station) l Connect IR    periscope power cable (CKT 5 17)   to   IR periscope. l Set   MASTER BATTERY switch ON, l Set   NIGHT VISION switch ON. l Operate IR    periscope (TM5-5420-226-10). l Check for   clear    image    while    looking through periscope eyepiece. Can   clear    image    be   seen    through eyepiece? CKT T 5 00 —–. _“-——--’’\’> a fk%i!’ .—.’ —. ) — I_ ,’ 516 Replace unserviceable IR “ Ie=l^{powerpack(page10-152).} NO I l Original IR   periscope is unserviceable. Replace unserviceable IR   periscope (page 10-152). l Install    floor    accoaa cover (page 17-9). 4-684 TA107373