Miller XMT 450 CC, Техническое руководство, Страница: 45 / 84

PRE-POWER CHECKS
TM-257 220 Page 41 XMT 450 CC/CV
10-5. Interconnect Board PC2
Ref. 255 761-A / 233 080-D
!
Read and follow safety
information in Section 10-1
before proceeding.
!
Wear an earth grounded wrist
strap when performing
pre-power and power off
checks. Remove wrist strap
before performing any checks
or procedures with power ap-
plied to the machine.
D1
Interconnect
Board PC2
D2
C5, C6 C3, C4
R14, R15
R1, R6,
R12, R13
R4/R17
R3/R16
Interconnect board PC2 provides electrical connections for SR1, PM1, PM2, C3, C4, C5, C6, L1, L3 and L4. It contains snubber circuits (D1,
C2, R6, R13) and (D2, C1, R1, R12), pre-charge resistors (R14, R15), and bus discharge resistors (parallel combination R3/R16, R4/R17).
1. Visually inspect components for damage. If there is visual evidence of damage such as smoke/debris or found to be defective using this
procedure, replace interconnect board.
2. Check diodes D1 and D2 using diode check on DMM. Look for diode drop of .2 to .9 VDC across the following terminals:
Positive Meter Lead Negative Meter Lead
D1 Anode (A) D1 Cathode (K)
D2 Anode (A) D2 Cathode (K)
3. Check resistance using ohms position on DMM of the following resistors:
R6, R13, R1, R12 1K ohms
R14, R15 40 ohms
R3, R16, R4, R17 19.5K ohms
Measurements may require several minutes because bus capacitors C3, C4, C5, and C6 are connected. An alternative method is to isol-
ate interconnect board from capacitors with insulating material after removing capacitor terminal screws. Re-install terminal screws after
checking before continuing.
4. Check bus capacitors C3, C4, C5, and C6 for a short using the ohms position on the DMM.