Metcal QX2 Manuel D'utilisation page 7

The preheater is designed to aid in the removal or the re-attachment of components
from a PCB safely and easily. The preheater uses forced convection to heat the entire
PCB evenly to just below the melting temperature of solder, allowing easy component
placement and removal, while minimizing the possibility of warping the PCB.
Plug the phone-style cable into the jack on the bottom of the preheater. Place the
preheater on a suitable workbench and stretch out the power cord and the phone
style cable behind the preheater.
WARNING: To provide protection against the risk of electrical shock, connect only to
properly grounded wall outlets.
Option 1
Lift the QX2 and place it over the preheater cables so that the cables are in the
grooves under the QX2. Place the three tabs in the back of the preheater over the
three slots in the base of the QX2. The preheater On/Off button and airflow control
knob will be facing you. Gently pull the preheater cables from the back of the QX2 to
remove any slack. Plug the phone-style connector into the jack on the back of the
QX2. Plug the preheater power cable into a grounded outlet.
Option 2
Place the preheater on the workbench ensuring that On/Off button and airflow control
knob are facing either your right or left. Plug the phone-style connector into the jack
on the back of the QX2. Plug the preheater power cable into a grounded outlet.
The preheater is now set-up and ready to aid in the rework of your first component.
The preheater delivers hot air to the bottom of the PCB. There are four power settings,
controlled by the airflow control knob (see figure above). The settings correlate to power
delivery of 150 to 950 watts, resulting in a PCB temperature range of 90 to 120ºC, with
an average across-board temperature gradient of 2ºC/cm. Choose a power setting
appropriate for your application. Use a higher setting for larger PCBs and quicker
removals. Use a lower setting for smaller PCBs and lower temperature ramp rates.
To start the preheater, press the On/Off Button. If the preheater is connected to the QX2,
it will turn on or off automatically with the QX2 operation cycle. To start the preheater
before the QX2, simply press the On/Off button prior to operating the QX2 unit.
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Copyright © 1999, Metcal, Inc. All Rights Reserved 7036-0541 Rev. A
PREHEATER
OVERVIEW
SET-UP
Airflow Control
On/Off Button
OPERATION
VACUUM CUP
ATTACHMENT
Remove the nozzle (see Nozzle Removal, p.12.)
Choose a vacuum cup that is properly sized for the component and the nozzle.
Push the vacuum cup up onto the vacuum tube. The vacuum tube will automatically
stop with the correct length of tube extended for the vacuum cup. DO NOT hold the
tube at the top or the cup will not be attached properly.
Be sure that the cup is attached level, so it will rest flush on the component. Vacuum
cups that are cocked may not hold a component.
REMOVAL
Remove the nozzle.
Use the notch in the Nozzle Removal Tool to pull the vacuum cup from the vacuum tube.
WARNING: The nozzle, cup and heater head may be hot.
MAINTENANCE
A clean and pliable vacuum cup is critical to proper component removal. Vacuum
cups will degrade over time and should be changed when they become brittle,
cracked, or torn. They should also be wiped cleaned of dirt and debris as necessary.
(See also Troubleshooting, p.14).
VACUUM TUBE MAINTENANCE
Over time, the vacuum tube may become clogged, especially if you have been using
flux, which can condense inside the tube. To clean the tube, first turn the system off
and allow it to cool. Then remove the flexible vacuum hose from the top of the tube at
the top of the heater head, and remove the vacuum cup from the bottom of the tube.
Run a stiff wire or rod (maximum diameter: 1.53mm) through the tube to clean it out.
Copyright © 1999, Metcal, Inc. All Rights Reserved 7036-0541 Rev. A
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