
MEP 660 - Trouble shooting Manual
Doc No.: IM – 51
Rev.2.0
Print: October 2008
123
valve coil terminal (Cable ID: AY, Pin-H). If necessary replace
the cable.
c) If the continuity is good and there is no slackness in
connector, then the digital output card MLSD 16 in slot No. 14
is defective. Replace the card.
10. If S21 is picking up, check the status of Green LED 10 on the digital
input card 2 in slot 10.
11. If the Green LED 10 is not glowing, check supply Voltage at
auxiliary contact (wire No. 51) with respect to locomotive 4 wire.
A. If voltage is zero, check the continuity of 51-wire loop coming to
S21 power contactor auxiliary contact.
12. If voltage is more than 65V, then check voltage at auxiliary contact
(wire no. S21FB) with respect to locomotive 4 wire.
A. If voltage is zero, the auxiliary contact is bad. Replace the
auxiliary contacts.
13. If voltage is more than 60 V,
A. Check the slackness of connector of cable ID: AU at MEP-660. If
slack tighten and check the LED status.
B. Check the continuity of Wire S21FB from S21 power contactor to
MEP-660. (Cable ID: AU, Pin-L). If necessary replace the cable.
14. If the Green LED 10
is glowing:
A. Check the status of corresponding Yellow LED on the same card.
B. If the yellow LED is not glowing, then the digital input card MDIP
16 in slot No. 10 is defective. Replace the card and check.
15. If Both Green and Yellow LEDs 10 are glowing on the digital input
card MDIP 16 in slot 10, the feed back status should be displayed
ON. Toggle the S21 contactor operation two to three times and
ensure the feedback signal is changing accordingly.