Tweco 7-3360 User Manual

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Manual 0-2555

82 Benning Street, West Lebanon, NH 03784 USA

[phone] • www.thermal-dynamics.com

General Information

NOTE

The installation of this replacement kit should only
be performed by a qualified electronic technician.

This Kit replaces the Driver PC Board, Shunt Amp PC Board,
Switching T ransistor/IGBT Assembly, and IGBT wire har­ness in the Merlin Series Power Supplies. The kit includes
an IGBT Suppressor PC Board.

W ARNING

If any of the parts listed above have failed, all must
be replaced at the same time with parts provided in
this kit. Failure to replace all parts together may
lead to parts failure.

Merlin Power Driver PC

Board Replacement Kit

Catalog # 7-3360

Installation Instructions

The kit also includes:

• Installation Instructions

• Static Dissipative Bag

• Grounding W rist Strap

• Static Handling Instructions

Installation Procedure

W ARNING

Disconnect primary power at the source before as­sembling or disassembling power supply, torch
parts, or torch and leads assemblies.

A. Opening Enclosure

Kit Contents

Rear of Front Panel

river PC Board

IGBT Suppressor
PC Board

IGBT

hermal Pad

hunt Amp PC Board

ire Harness

1. Turn OFF main input power to the Power Supply both at the
Power Supply ON/OFF switch and at the main power dis­connect.

2. W ait at least two minutes to allow the input capacitors
to discharge.

3. Remove the top and side panels of the Power Supply.
T o remove the top panel of the Power Supply r equires
the removal of several screws. Carefully remove all the
screws before attempting to remove the panels.

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Art # A-0608

B. Driver PC Board Assembly Installation

rd

R

U

rd

ls

Style With 3 T erminals

Art # A-06055

C. IGBT (Q1) Installation

1. Locate the old Driver PC Board Assembly on the inside
left side, behind the front panel, as viewed from the
front of the unit.

ear of Front Panel

A-01083

Driver PC Boa

Driver PC Board Location

2. Note and label the two wiring connectors that connect
to the Driver PC Board.

3. Disconnect the two wiring connectors from the Driver
PC Board.

4. Press in the securing tab knob on the PC Board Guide
to release the PC Board from the PC Board Guides.
There is a securing tab on both the upper and lower PC
Board Guides.

1. Locate the old Switching Transistor/IGBT Assembly
on the inside center-left, between the four large blue
capacitors, as viewed from the front of the unit.

Transistor/Coil

Switching T r ansistor

Q1

Large Blue
Capacitors

Bracket

A-01085

2. There are two differ ent types of Switching T ransistor/
IGBT. The types can be identified by the top of the
transistor casing. This kit replaces both types.

Style With 2 T ermina

pper PC Board Guide

5. Carefully pull the PC Board from the guides and re­move from the unit.

6. Install the replacement Driver PC Board Assembly re­versing the above steps.

Securing T ab

Lower PC Boa

Securing T ab

PC Board Guide Securing Tab

Driver PC

Board

Guide

A-01084

Switching Transistor/IGBT Styles

3. Remove the two screws securing the wires to the Switch­ing Transistor/IGBT Assembly terminals. Remove
and discard the wire harness.

4. Remove the screw that secures the Capacitor Mount­ing Bracket to the Switching T ransistor/IGBT Assem­bly.

5. Remove the screw that secures the Transistor/Coil
Bracket to the Switching T ransistor/IGBT Assembly.

6. Remove the screw and washer securing the PTC Resis­tor Assembly to the Main Heatsink. Move the PTC
Resistor Assembly out of the way to prevent it from
becoming damaged.

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or

A

6. Connect Harness.

D. Shunt Amp PCB Replacement

PTC Resist

Assembly

Q1

rt # A-01089

Main Heatsink

PTC Resistor Assembly Location

7. Remove the four screws securing the Switching T ran­sistor/IGBT module to the Main Heatsink. Be careful
not to damage the surface of the heatsink.

8. Pry between the Main Heatsink and the faulty Switch­ing T ransistor/IGBT Assembly until it slides easily.

9. Remove the faulty Switching T ransistor/IGBT Assem­bly from the unit by sliding it towards the center of the
Main Heatsink.

10. If the transistor thermal pad was not removed with the
transistor, r emove it now .

1. Locate the Shunt Amp PCB, mounted to the Shunt on the
main heatsink.

2. Use the grounding wrist strap provided separately in
this kit. Follow all static handing instructions on the
separate instruction sheet.

3. Open two locking tabs securing the ribbon cable con­nector to the Shunt Amp PCB. Carefully remove the
cable connector from the Shunt Amp PCB.

4. Loosen, but do not remove, the bolt securing the Shunt
to the main heatsink, to allow access to screws secur­ing the Shunt Amp PCB to the Shunt.

Rear of Power Supply

Shunt

Main Heatsink

Shunt

Amp PCB

Ribbon

Cable

11. Use isoproply alcohol to clean the residue of the old tran­sistor thermal pad from the transistor mounting area.

12. Install the replacement Thermal pad, the IGBT Assem­bly , IGBT Suppr essor PC Board, and the replacement
wire harness included in this kit in the sequence
shown. Note the torque requirements. Connect the
other end of the harness to the terminal from which the
previous harness was disconnected, on the driver PC
board.

5. Install IGBT
Suppressor
PC Board.
Torque hardware
to 14 in-lbs.
(1.6 N-m).

4. Torque IGBT
hardware (only)
to 26 in-lbs.
(2.9 N-m).

3. Remove

copper tape.

1

3

1

Art # A-03839

Shunt Amp PCB Disconnection

2

2. Install IGBT.

1. Install Thermal Pad.

IGBT Installation Sequence

Art # A-06083

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5. Loosen, but do not remove, the screws securing the

R

Shunt Amp PCB to the Shunt.

6. Refer to the illustration. Remove the Shunt Amp PCB
from the power supply . Lift the end of the PCB closer to
the rear of the Power Supply, and slide the PCB rear­ward to release it fr om the forward screw.

ear of Power Supply

3

8. Position the replacement Shunt Amp PCB on the Shunt.
Secure with the hardware loosened pr eviously . T ighten
securely . Do not overtighten.

9. Fasten the Shunt to the main heatsink by tightening
the bolt loosened previously . T ighten securely. Do not
overtighten.

10. Align the ribbon cable connector with the receptacle
on the Shunt Amp PCB. Press the connector fully into
the receptacle. Close the two locking tabs on the recep­tacle. Check for a secure connection.

11. Reinstall the power supply outer panels.

2

1

Art # A-03850

Shunt Amp PCB Removal

7. If necessary , carefully clean the PCB mounting surfaces
on the shunt. Wipe the surfaces clean with a lint-fr ee
rag.

CAUTION

Do not use conductive material such as steel
wool to clean the mounting surfaces.

This completes the installation of the Replacement Kit.

NOTE

Every effort has been made to provide complete
and accurate information in this manual. How­ever , the publisher does not assume and hereby
disclaims any liability to any party for any loss
or damage caused by errors or omissions in
this Manual, whether such errors result from
negligence, accident, or any other cause.

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