TM 11-5821-333-30
6-20. OPERATIONAL CHECK. Continued
ACTION
RESPONSE
Step 15. REFERENCE RCU TEST. Continued
b. Set ref rcu FUNCTION switch to Z-A then
TEST,
c. Set ref rcu FUNCTION switch to SQ ON.
d. Disconnect test cable W12 from J2.
e. Use ext probe to check voltage at J2-H.
1.
Reconnect test cable W12 to J2.
g.
Press ref rcu • ••/TIME key.
h. Set test adapter–
S1:3
TEST EQPT INPUT (S14) : INTL
TEST EQUIPMENT SELECTOR (S15) : SCOPE
i.
Set ref rcu FUNCTION switch to SQ OFF.
j.
Set test adapter–
S1: OFF
S3: 11
TEST EQUIPMENT SELECTOR (S15) : DMM
k. Set ref rcu FUNCTION switch to RXMT.
b. Ref rt display read:
.- - - - -
“ for 3s (ref rt is “30000”)
“E
-“ for 2s
NOTE: Ignore displays after “ E -”.
If not, go to chart 12.
c. Ref rcu display reads “30000”.
If not, ref rcu is bad.
d. No response.
e. DMM reading is 24 to 31 V dc. If not, replace
lamp test CCA. If still bad, go to troubleshoot-
ing schematic 11.
f. No response.
g. Ref rcu display reads “00 “.
If not, ref rcu is bad.
h. No response.
i.
Scope channel 1 displays noise signal with a
level greater than or equal to 5 V P-P.
If not, go to chart 13.
j.
No response.
k. DMM reading is greater than or equal to 6 V
dc. If not, go to chart 15.
6-173
