Thermal Dynamics MERLIN 6000, Service Manual, Page: 30 / 112

SERVICE TROUBLESHOOTING 24 Manual 0-2569
4. Main current control on remote or front panel set too
low
a. Main current may not be high enough for metal
thickness being pierced. Refer to torch manu-
als for recommended settings.
5. Pierce delay too short
a. Increase pierce delay to allow more pierce time
before starting torch motion
6. Actual current is lower than the current control setting
a. For outputs greater than 150A make sure Slave
Power Supply is turned ON, Parallel Cable is
connected and the Slave Power Supply Work
Lead is connected
b. Current Control circuit is faulty; Refer to Sec-
tion 4.05-P, Current Control, Display, and CSD
Checks
U. Main arc transfers and pierces through the plate,
but cutting machine doesn’t move
1. Incorrect or missing OK-To-Move signal.
a. Many cutting machines require an AC voltage
to activate the motion input. Refer to Operat-
ing Manuals for setting OK-To-Move signal.
b. Check for missing OK-To-Move signal. Refer to
Section 4.05-R, OK-To-Move Tests.
V. Standoff Control Not Working Correctly
Refer to Troubleshooting in the Standoff Control In-
struction Manual.
W. Remote Control Not Working Correctly
Refer to Troubleshooting in the Remote Control In-
struction Manual.
4.05 Test Procedures
The following tests are suggested for specific problems
listed in the troubleshooting guide.
WARNING
Several of these tests involve voltage measurements
that must be made with power on. Use extreme
care when making these tests. Tests requiring volt-
age measurements are marked with the warning
symbol. Disconnect primary power to the system
for all other tests.
A. Voltage Selection PC Board Check
The Merlin transformer has three input voltage ranges
(200-230, 380-460 and 500-575) selected by buss bars.
Within each range there are transformer taps for the up-
per and lower halves of the range. The dividing line be-
tween the upper and lower halves for each range are as
follows:
• 200 - 230 VAC; approximately 207 VAC
• 380 - 460 VAC; approximately 409 VAC
• 500 - 575 VAC; approximately 509 VAC
The Voltage Selection PCB automatically selects the cor-
rect taps.
NOTE
The connector for the following tests on the Volt-
age Selection PC Board is labelled J1. The System
Schematic and the other supplied data refers to this
connector as J6.
Voltage Selection Test
A one second delay after wall power is turned ON,
when the voltage at J6-20 to J6-22 is greater than 28
VAC (upper half of range), the Voltage Select PCB en-
ables relays K1, K4 and K5 (labeled ‘HV’ on the sys-
tem schematic) and the red LED, D18. The relays and
LED will not turn ON unless switch SW1, front panel
ON/OFF Switch is ON.
• If the voltage at J6-20 to J6-22 is less than 28 VAC,
then relays K2 and K3 (labeled ‘LV’ on the system
schematic) are enabled and LED, D18, will not
come ON.
• If LED, D18, is ON and the voltage is less than 28
VAC replace the Voltage Selection PCB.
28 VAC Test
1. Check the AC input from J6-24 to both J6-20 and
J6-22 for 12 - 18 VAC.
2. Check the AC voltage from J6-24 to both J6-17 and
J6-18 for 16 - 22 VAC.
3. If input voltages are correct, check output from J6-
24 to both J6-19 and J6-21 for 14 - 18 VAC.
4. If output is not present at J6-19 and J6-21, check
between J6-24 (-) and both J6-16 and J6-23 (+) for
12 - 16 vdc. If voltage is present at both points or
neither, replace the Voltage Selection PC Board. If
voltage is found at J6-23 but not at J6-16, check
SW1-B and all wiring and connections.