Thermal Dynamics MERLIN 6000, Service Manual, Page: 26 / 112

SERVICE TROUBLESHOOTING 20 Manual 0-2569
3. Locate your symptom in the appropriate Sub-Section.
4. Check the causes (easiest listed first) for the symptom.
5. Check the remedies listed for each cause.
6. Repair as needed being sure to verify that unit is fully
operational after any repairs.
NOTE
Many signals are transfered between Printed
Circiut Board Assemblies on Ribbon Cables. If
these cables become faulty they can then cause vari-
ous problems. Do not forget about these cables
when troubleshooting.
A. No front panel LED indicators ON; Fan and pump
not operating
1. No primary power. Refer to symptoms C and D also.
a. Check for proper three-phase power at input
terminal board
2. Faulty ON/OFF switch (SW1)
a. Disconnect primary power. Check each section
for continuity. Replace switch if necessary
3. Faulty voltage selection board
a. Refer to Section 4.05-A, Voltage Selection PC
Board Check. Replace Voltage Selection PC
Board if necessary
B. AC indicator ON; Fan or pump not operating
1. ENABLE signal not ON or faulty
a. Remote ENABLE or ENABLE at TB2 must be
ON. Refer to Section 4.05-B, Enable Circuit Test.
2. Blown fuse (F1 or F2)
a. Check and replace fuse if necessary. Refer to
Section 4.05-C, Blown Fuse (F1 or F2).
3. Faulty ON/OFF switch (SW1)
a. Disconnect primary power. Check each section
for continuity. Replace switch if necessary
4. Faulty Voltage Selection PC Board
a. Refer to 4.05-A, Voltage Selection PC Board
Check. Replace Voltage Selection PC Board if
necessary
5. Faulty motor contactor (MC1, MC2 or MC3)
a. Refer to Section 4.05-D, Motor Control Contac-
tor Check (MC1, MC2 or MC3). Replace con-
tactor if necessary
6. Parallel cable not connected (Slave Power Supply)
a. Install Parallel Cable
7. No ENABLE to Slave Power Supply
a. Refer to Section 4.05-T, Isolation PCB and Par-
allel Cable Interface
C. No indicators are on for the RC6010 or SC10
remotes.
1. No +48 vdc power to the remotes.
a. 3 amp fuse blown on the Bias PCB, replace.
b. Defective Bias PCB, Refer to Section 4.05-Q, 48
Volt Bias Test.
D. AMPS or VOLTS displays not on for RC6010 or
SC10.
1. Normal if ENABLE not on.
a. Turn on ENABLE at RC6010
b. Defective ENABLE circuit, Refer to Section 4.05-
B, Enable Circuit Test.
2. Faulty Remote Device
a. Replace as needed
E. Fuse blows at disconnect when primary power is
turned ON
1. Voltage selection busbars connected incorrectly
a. Check and correct if necessary.
2. One leg of three-phase primary connected to chassis
ground
a. Rewire input cable per Operating Manual.
3. Main transformer shorted
a. Replace main transformer
F. Fuse blows at disconnect when main contactor (W1
or W2) closes
1. Shorted input diode (D1-D6)
a. Refer to Section 4.05-E, Diode Check. Replace
diode(s) as required.
2. Switching transistor (Q1) shorted to heatsink
a. Replace Q1, check heat-sink for possible dam-
age. Refer to Section 4.05-M, Switching Con-
trol Check (Q1).
3. Shorted input capacitor (C7-C12)
a. Replace capacitor if necessary