Master VT D Series User manual

Models: VT-751D, VT-752D
VT Service Manual -D Series

VT-751D and VT-752D
Master Appliance Corp.
2420 18th St.
Racine, WI 53403-2381 USA
Tel: [phone]
Email: [e-mail]
www.masterappliance.com
58279E REV A
pg. 1 of 7
Available kits
Motor Replacement- Part No’s. 30073 (120V), 30074 (220-240V)
Element Connector Replacement–30089
Switch & Bezel Kits Replacement–30075
VT Dial, Support, & Gear Kit –Part No. 30092
Circuit Board Kits –30093 (VT-751D, 120V), 30094 (VT-752D, 220-240V)
Cordset Replacement-–30079 (120V 15 Amp), 30081 (220V UL/CUL)
30097 (220-240V EU), 30098 (220-240V UK)
Nozzle shield replacement 30077
Handle Replacement 30091
What’s in the kit
MOTOR KIT:
•MOTOR, (1)
•SCREW, #6-32 x .50 LONG (2)
•SCREW, M3 x 0.5 x 10mm LONG (1)
•CABLE TIE (2)
•SHRINK TUBE (1)
DIAL, SUPPORT, & GEAR KIT:
•DIAL, VT, (1)
•SUPPORT, VT, (1)
•GEAR, VT, (1)
•NUT, HEX, #6-32, (1)
•SCREW, #6-32, (1)
•SCREW, #6-32 x .50, (2)
CIRCUIT BOARD KIT:
•CIRCUIT BOARD, (1)
•SCREW, #6-32 x .38, (2)
•SHRINK TUBE, (1)
•LABEL, MODEL, (1)
NOZZLE SHIELD KIT
•NOZZLE ASSEMBLY, (1)
•SHIELD, (1)
•SCREW, #6-32, (2)
HANDLE KIT
•HANDLE SET RT & LT (1)
•SCREWS, #6-19, (4)
ELEMENT CONNECTOR KIT:
•ELEMENT CONNECTOR ASSY (1)
•CABLE TIE (2)
•SHRINK TUBE (2)
SWITCH & BEZEL KIT:
•SWITCH/BEZEL/JUMPER ASSY (1)
•BARRIER, ELECTRICAL (1)
CORDSET KIT:
•CORDSET (1)
•CABLE GUARD (1)
•SCREW, #6-32 x .31 GREEN (1)
•CABLE TIE (2)
•SHRINK TUBE (1)
•CORD CLAMP, USED WITH (220 –240 VAC) units (1)
TOOLS REQUIRED
#1 DRIVE PHILLIPS
SCREWDRIVER
#2 DRIVE PHILLIPS
SCREWDRIVER
1/8 inch HEX KEY
(ALLEN WRENCH)
UTILITY KNIFE
MASTER HEAT GUN REPLACEMENT PARTS AND ACCESSORIES ARE ENGINEERED AND MANUFACTURED TO PRECISE MASTER APPLIANCE SPECIFICATIONS. REPLACEMENT PARTS AND ACCESSORIES FROM
OTHER MANUFACTURERS ARE NOT PRODUCED TO THESE PRECISE SPECIFICATIONS. FAILURE TO USE MASTER APPLIANCE REPLACEMENT PARTS OR FAILURE TO INSTALL MASTER APPLIANCE REPLACEMENT
PARTS EXACTLY AS INSTRUCTED MAY CAUSE PHYSICAL INJURY OR DAMAGE TO THE HEAT GUN. MASTER APPLIANCE CANNOT ASSUME RESPONSIBILITY FOR PHYSICAL INJURY OR DAMAGE TO THE HEAT GUN
RESULTING FROM THE USE OF ANY OTHER BRAND OF REPLACEMENT PART OR IMPROPER INSTALLATION OF MASTER APPLIANCE REPLACEMENT PARTS OR ACCESSORIES.
WARNING: Disconnect heat gun power cord and allow the heat gun to cool before disassembly.
READ THE SERVICE INSTRUCTIONS CAREFULLY. FAILURE TO EXACTLY FOLLOW THE INSTRUCTIONS
COULD RESULT IN PERSONAL INJURY OR DAMAGE TO YOUR HEAT GUN. ALL REPAIRS MUST BE
PERFORMED BY A QUALIFIED REPAIR TECHNICIAN.
AVERTISSEMENT : Débrancher le cordon du pistolet thermique et laisser celui-ci refroidir avant de le
démonter.
LIRE ATTENTIVEMENT LES INSTRUCTIONS D’ENTRETIEN. OMETTRE D’OBSERVER EXACTEMENT CES
INSTRUCTIONS POURRAIT ENTRAÎNER DES BLESSURES OU ENDOMMAGER VOTRE PISTOLET THERMIQUE.
SEUL UN RÉPARATEUR QUALIFIÉ PEUT EFFECTUER LES RÉPARATIONS.
ADVERTENCIA: Desconecte el cable de la pistola térmica y deje que ésta se enfríe antes de desarmarla.
LEA CON ATENCIÓN LAS INSTRUCCIONES DE SERVICIO. EL NO SEGUIR EXACTAMENTE LAS
INSTRUCCIONES PUEDE RESULTAR EN DAÑO A LA PISTOLA TÉRMICA. TODAS LAS REPARACIONES DEBEN
SER REALIZADAS POR UN TÉCNICO DE REPARACIONES CALIFICADO.
Do not touch
nozzle until cool
Ne pas toucher la
buse avant qu’elle
ait refroidi
No toque
la boquilla hasta que
se haya enfriado
1/4 inch SOCKET
AND DRIVER

VT-751D and VT-752D
Master Appliance Corp.
2420 18th St.
Racine, WI 53403-2381 USA
Tel: [phone]
Email: [e-mail]
www.masterappliance.com
58279E REV A
pg. 2 of 7
Ⓜ
#6-32 SCREW (2)
Ⓗ
Ⓐ
Figure 1
HANDLE, RIGHT
HOUSING
SCREWS (2)
Ⓗ
ELECTRICAL
BARRIER
Ⓥ
COVER
BLOWER WHEEL
HANDLE, LEFT
GROUND SCREW, GREEN
CORDSET
CABLE
GUARD
HOUSING,
METAL
HANDLE SCREWS (4)
Ⓙ
BEZEL / SWITCH / JUMPER
NOZZLE
AND
SHIELD
NOZZLE SCREWS,
(2)
Ⓦ
ELEMENT
CIRCUIT BOARD,
KIT #30093 FOR VT-750D, (120V)
KIT #30094 FOR VT-752D, (220-240V)
SHRINK TUBE
SHRINK TUBE
Ⓣ
ELEMENT
CONNECTOR
MOTOR
MOTOR
SCREWS
(2)
Ⓛ
Ⓖ
SCREWS (2)
Ⓜ
Ⓦ
Ⓗ
Figure 2
BOLT, HEX,
#6-32
Ⓕ
SCREW, M3x0.5
x 10mm long,
ATTACHED TO
MOTOR FRAME
Ⓚ
STEM, KNURLED
SUPPORT
Ⓔ
GEAR
Ⓒ
SCREW, Round Head,
#6-32 x .50, QTY 2
Ⓓ
DIAL
Ⓑ
NUT, HEX, #6-32,
Ⓐ
LABEL
CUT SMALL INCISION
THRU CENTER OF LABEL
TO LOOSEN NUT
SPRING
WASHER

VT-751D and VT-752D
Master Appliance Corp.
2420 18th St.
Racine, WI 53403-2381 USA
Tel: [phone]
Email: [e-mail]
www.masterappliance.com
58279E REV A
pg. 3 of 7
DISASSEMBLY INSTRUCTIONS
UNPLUG HEAT GUN. TAKE NOTE OF WIRING LAYOUT.
To remove dial, gear and support (Figure 2)
NOTE: Dial, Gear, and Support must be removed to remove the
circuit board and motor.
1. Cut small incision thru center of label on dial to expose the #6-32
nut Ⓐ. and washer.
2. Loosen the #6-32 nut, Ⓐand remove the dial Ⓑ, spring and
the gear Ⓒ. The nut and washer Ⓐcan remain assembled
between the label and the dial.
3. Remove the two (2) round head screws Ⓓ,then remove the
support Ⓔand the hex bolt Ⓕ.
To remove cover and handle halves (Figure 1)
1. Remove two (2) nozzle mounting screws Ⓦat the rear of the
shield. If nozzle mounting screws are lost or damaged, replace
only with #6-32 steel machine screws, 3/16-inch minimum length
to 1/2- inch maximum length.
2. Gently pull shield from gun housing. Shield, nozzle and mica
insulator may come apart as one unit. Pull element out of
housing.
3. Remove (2) housing screws (#6-32 x .50) Ⓗand remove cover.
4. Remove (4) handle screws (#6-19 x .63 long) Ⓙand remove
handles from housing.
To remove the motor (Figure 1)
1. Loosen the set screw in the blower wheel with a 1/8 hex key
wrench, then remove the blower wheel from the motor. Remove
screw Ⓚfrom the bottom of the housing. (Figure 2).
2. Place the heat gun on a flat surface with the motor facing
upward. Remove (2) outer screws Ⓛon the top flange of the
motor. Gently pull the motor straight up and out of the housing,
taking care not to disconnect the white or black wire terminals.
Set the motor on the outside of the housing. If wires become
disconnected, see motor assembly instructions for proper wiring
locations.
To disconnect electrical terminals for the motor kit, the element
connector kit, and the cordset kit (not required for switch/bezel kit
or circuit board kit):
1. Cut and remove the existing cable ties and shrink tube to expose
the quick-connect terminals (Figure 3).
2. Disconnect the black lead wire of the motor from the switch.
Disconnect the white lead wire of the motor from the piggyback
terminal on the white wire from the element connector.
To remove the switch/bezel assembly:
1. Lift the switch/bezel assembly away from the handle, being
careful not to break the tabs of the handle (Figure 4) .
Disconnect all wires from the switch.
To remove the circuit board:
1. Remove the #6-32 pan head screws (2 screws) Ⓜfrom the top
of the circuit board. (Figure 1). Remove the shrink tube over the
terminals of the black wires between the circuit board and the
element connector Ⓣ(Figure 5).
2. Disconnect the terminals Ⓟ. (Figure 5).
3. Disconnect the circuit board from the switch Ⓝ(Figure 5).
4. Remove the circuit board.
SWITCH / BEZEL
Figure 4
TABS IN
HANDLE
Ⓟ
WIRE FROM CIRCUIT BOARD
CONNECTS TO BLACK WIRE OF
ELEMENT CONNECTOR. COVER
CONNECTION WITH SHRINK TUBE
BLACK WIRE FROM CIRCUIT BOARD
CONNECTS TO SWITCH
Ⓝ
CIRCUIT BOARD
ELEMENT
CONNECTOR
Figure 5
Ⓣ
SHRINK TUBE
Figure 3
CABLE TIES
TERMINALS
SHRINK TUBE

VT-751D and VT-752D
Master Appliance Corp.
2420 18th St.
Racine, WI 53403-2381 USA
Tel: [phone]
Email: [e-mail]
www.masterappliance.com
58279E REV A
pg. 4 of 7
Figure 7
SHRINK TUBE MUST COVER
TERMINALS OF WHITE WIRE FROM
CORDSET, MOTOR AND ELEMENT
HOLDER,
SHRINK TUBE,
MOVE TO COVER
TERMINALS
Ⓣ
ELEMENT
HOLDER
BLACK WIRES MUST
CLEAR SCREW
BOSSES
To remove the element connector:
1. Disconnect the black lead wire of the element connector from
circuit board (Figure 5). Disconnect the white lead wire of the
element connector (with piggyback terminal) from both the white
wire of the motor and the white wire of the cordset (Figure 3).
To remove the cordset:
1. Remove the green ground screw located near the nozzle of the
housing (Figure 1). Remove the black cordset wire from the
piggyback terminal of the jumper, (Figure 6). Remove the white
cordset wire from the piggyback terminal on the white wire from
the element connector (Figure 3). Lift the cable guard out of the
handle and remove the cordset.
INSTALLATION INSTRUCTIONS
To install the new CIRCUIT BOARD:
1. Place the circuit board into the housing with the knurled stem
protruding through the hole at the bottom of the housing
(Figure 7).
2. Assemble the #6-32 pan head screws Ⓜ(2 screws) to retain the
circuit board, and tighten to 12 –15 in-lbs torque (Figure 1).
3. Connect the terminal of the black wire from the new circuit board
to the switch Ⓝ(Figure 8).
4. Assemble the new shrink tube Ⓣover the black wire from the
element connector (Figure 5 & 7).
5. Connect the black wire from the new circuit board to the black
wire from the element holder Ⓟ. The new shrink tube Ⓣmust
be positioned over the terminals (Figure 5).
To install the MOTOR:
1. Ensure the black motor wire is connected to the switch Ⓢ
(Figure 8).
2. Connect the white motor wire to the piggyback terminal of the
white element connector wire and white wire from cordset
(Figure 3).
3. Assemble motor into housing and with (2) #6-32 x .50 long
screws Ⓛ(Figure 1). Torque to 16 –20 in-lbs.
4. Assemble (1) M3 x 0.5 Ⓚ(Figure 2) through back side of
housing and into motor frame at a torque of 2-5 in-lbs.
Excessive torque will warp the motor frame, resulting in reduced
air flow and damage to the motor.
5. Assemble blower wheel onto shaft of motor and tighten set
screw with 1/8 inch hex key. Top of blower wheel hub must be
flush with top of motor shaft. Must not rub against frame of
motor and must not rub against wiring (Figure 9).
To install the ELEMENT CONNECTOR:
1. Connect the black wire from the new element connector to the
black wire from the circuit board Ⓟ. The new shrink tube Ⓣ
must be positioned over the terminals (Figure 5).
2. Connect the white wire of the element connector to the white
wires from the motor and cordset (Figure 10). Position the
shrink tube over the terminal from the motor and from the
cordset after the terminals are connected.
WARNING: Failure to cover the terminals with
shrink tubing
Ⓣ
could result in electrical short
SWITCH
TERMINALS
CIRCUIT BOARD
BLACK WIRE
MOTOR
BLACK WIRE
Ⓢ
JUMPER
BLACK WIRE
BLACK
JUMPER
WIRE
Figure 8
Ⓝ
Figure 9
SHAFT FLUSH WITH
TOP OF FAN HUB
WARNING: Failure to cover the terminals with
shrink tubing
Ⓣ
could result in electrical short
WARNING: Failure to cover the terminals with
shrink tubing could result in electrical short
Figure 6
BLACK CORDSET
WIRE

VT-751D and VT-752D
Master Appliance Corp.
2420 18th St.
Racine, WI 53403-2381 USA
Tel: [phone]
Email: [e-mail]
www.masterappliance.com
58279E REV A
pg. 5 of 7
To install the CORDSET:
1. Install new cable ties in metal housing (Figure 11).
2. Connect the green cordset wire to the enclosure’s ground post
using the green screw (Figure 1).
3. Connect the black cordset wire to the jumper’s piggyback
terminal attached to the switch (Figure 10).
4. Connect the white cordset wire to the element connector’s white
wire piggyback terminal (Figure 3).
5. On 220-240V cordsets use supplied cord clamp (figure 11).
To install the SWITCH / BEZEL ASSEMBLY:
1. Connect the wires to the appropriate switch terminals per
instructions above (Figure 8 &10). The black jumper wire is to
wrap around the white wires from the motor and element
connector, and also the green wire from the cordset. Attach the
piggyback terminal of the jumper to the switch, and the other end
of the jumper to the switch (Figure 10).
2. Place the electrical barrier Ⓥbetween the switch and the
housing.
3. Align the three holes of the bezel with the three tabs in the
handle and gently press the switch / bezel assembly into position
as shown (Figure 4).
4. Position the shrink tube over the piggyback terminal and over
the white wire terminals from the motor and from the cordset.
Use cable ties to hold in place (Figure 11).
To install the HANDLES and COVER: (Figure 11)
1. Hook the left handle onto the handle portion of the metal
housing.
2. Install switch bezel assembly per above.
3. Ensure the electrical barrier Ⓥis positioned between the
terminals of the switch and the housing.
4. Route wires in channels (Figure 11) and chinch cable ties to hold
wiring in place.
5. Align the three holes of the switch bezel with the three tabs in
the handle and gently press the switch / bezel assembly into
position as shown.
6. Ensure all wiring clears the screw holes of the handles and
gently assemble the right handle onto the housing. Retain with
#6-19 x .63 screws Ⓙ(4) (Figure 1). Tighten to 12 –15 in-lbs
torque.
7. Assemble cover onto housing and retain with housing screws,
#6-32 x .50 screws, Ⓗ(2) (Figure 1). Tighten to 16 - 20 in-lbs
torque.
JUMPER, (BLACK WIRE)
WHITE WIRES FROM ELEMENT
CONNECTOR (PIGGYBACK TERMINAL)
MOTOR & CORDSET
SHRINK TUBE
CORDSET BLACK WIRE
ON PIGGYBACK
TERMINAL OF JUMPER
Ⓝ
CIRCUIT BOARD
MOTOR BLACK WIRE
Figure 10
Ⓢ
ELECTRICAL BARRIER
Ⓥ
WARNING: Failure to insulate switch & wire terminals from
metal enclosure could result in electrical short
Figure 11
ENSURE WIRES STAY
CLEAR OF SCREW
HOLES AND HANDEL
PINCH POINTS TO
AVOID PINCHING
WIRES BETWEEN
HANDLES
ENSURE BARRIER
IS BETWEEN
TERMINAL AND
METAL HANDEL
ELEMENT
CONNECTOR
Ⓥ
CORD CLAMP BETWEEN
CORDSET AND METAL HOUSING,
ONLY USED ON EUROPEAN, U.K.,
AND 220-240V CORDSETS
WARNING: Failure to insulate switch & wire terminals from
metal enclosure could result in electrical short

VT-751D and VT-752D
Master Appliance Corp.
2420 18th St.
Racine, WI 53403-2381 USA
Tel: [phone]
Email: [e-mail]
www.masterappliance.com
58279E REV A
pg. 6 of 7
To install the SUPPORT, GEAR and DIAL:
1. Assemble #6-32 hex bolt Ⓕinto bottom of support Ⓔand attach
the support to housing with #6-32 x .50 inch screws Ⓓ(Figures
2).
2. Attach gear Ⓒto knurled stem and rotate fully counter-clockwise
(Figures 12).
3. Place wave spring into pocket of support Ⓔ(Figures 12).
4. Align the dial Ⓑwith the number “9” at the top and assemble
onto the support Ⓔ. If needed, rotate dial left or right to mesh
the teeth of the dial with the teeth of the gear (Figures 12).
5. Assemble the #6-32 nut Ⓐand washer into the center hole of
the dial. Do not over-tighten as this could cause damage to the
dial and support (Figures 2).
To install element nozzle and shield: (Figures 13 & 14)
1. Gently insert new element into housing, with contacts of element
contacts inserted fully into the contacts in the housing.
2. Wrap the mica insulator around coils of heater element, ensuring
all coils are covered.
3. Gently slide nozzle straight on, aligning ceramic element wings
with front nozzle indents and two (2) nozzle screw holes. Slide
shield over nozzle, aligning mounting holes. Install two (2)
nozzle screws Ⓦloosely until started, and then tighten.
AFTER HEAT GUN IS COMPLETELY ASSEMBLED, CONDUCT
FINAL ADJUSTMENT AND TEST:
1. Plug your Master Heat Gun®into a properly rated electrical
outlet.
2. Run in “Cool”mode, gently tap bottom of unit to align motor
bearings unit until motor noise stabiles.
3. Switch unit to “Hot”. Hot air should be blowing from nozzle.
4. Turn dial to from 1 to 9 to ensure temperature is adjusting.
New element
Element wings
Insert into contacts
Contacts in housing
New mica
Roll mica over coils of
element
Figure 13
Element
Mica
Nozzle
Indents align with element wings.
Shield
Figure 14
Ⓦ
Ⓦ
WARNING:
Failure to properly cover coils
with mica insulator could result in electrical short
Figure 12
ALIGN THE DIAL
Ⓑ
WITH THE NUMBER
“9” AT THE TOP
GEAR
Ⓒ
KNURLED STEM,
ROTATE FULLY CCW
SUPPORT
Ⓔ
WAVE SPRING

VT-751D and VT-752D
Master Appliance Corp.
2420 18th St.
Racine, WI 53403-2381 USA
Tel: [phone]
Email: [e-mail]
www.masterappliance.com
58279E REV A
pg. 7 of 7
TROUBLESHOOTING GUIDE
SYMPTOM
CAUSE
SOLUTION
Excessive Vibration
Motor screw not tight or missing
Recheck that all screws are present and tighten
to correct torque
Blower wheel loose or damaged
Tighten or replace blower wheel if damaged
Unusual Noise
Blower wheel not positioned correctly
on motor shaft
Ensure top of motor shaft is flush with top of
blower wheel hub
Wires rubbing on blower wheel
Ensure wires are in proper position and out of
way of blower wheel
Motor does not run
and element does not
heat
Unit is not plugged in
Plug in unit
Outlet is non-functional
Ensure outlet is live
Switch is not wired properly
Ensure switch is wired properly
Switch is damaged
Test switch and replace if defective
Motor does not run
but element heats
Switch is not wired properly
Ensure switch is wired properly
Switch is damaged
Test switch and replace if defective
Motor is damaged
Replace motor
Motor runs but no
heat
Heating element not install properly
Ensure male terminals of element were fully
seated in female contacts of element connector
Heating element damaged
Check element to see if coils are open, replace if
defective
Element connector damaged
Inspect element connector to see if damaged, if
damaged replace
Element connector, circuit board or
switch not wired correctly
Ensure element connector, circuit board and
switch are wired properly
Circuit board damaged
Test circuit board and replace if defective
Switch damaged
Test switch and replace if defective
Heating element
heats, but does not
adjust when dial is
turned
Dial and gear are not position correctly
Remove dial, turn gear fully counter clockwise,
reassemble dial with the “9” aligned with pointer
Circuit board is damaged
Test circuit board and replace if defective
Dial does not turn, or
full range of
movement not
available
Pot stem not turned or turned fully in
correct direction
Remove dial, turn gear fully counter clockwise,
reassemble dial with the “9” aligned with pointer
Dial is loose
Wave spring not installed
Remove dial and ensure wave spring is present,
reinstall dial