Quadra 4 Operator Manual
Tomtec
165
These Quadra tips are loaded by position on the tip pins. When fully loaded, there
should be less than 1/16 inch (.062 inches) clearance between the top of the disposable
tip and the Quadra shuck plate. This can be determined after loading a rack of 96 tips
by using your finger to push the tip tight against the shuck plate. It should not move
more than .062 inches. If it does, the Tip Load Switch must be adjusted. If the tip is
loaded tightly against the shuck plate, this also indicates the need to adjust the Tip Load
Switch.
The software will load the tips on command. If the instrument is unable to load the tips
on the first attempt, it will re-try 2 more times before displaying a “Tip Load Error”. If the
tip load switch does not break the contract, the tip load function fails.
If there is a problem loading tips, it is typically due to one of two causes:
1. The primary cause of the tip load failure can be loss of lubrication on the tip pin “O”
rings. Use the tip pin lubricator that was supplied with the Quadra (TOMTEC P/N 196-
107).
2. The tip load switch is not set properly. Check the clearance between the top of the tip
and the tip shuck plate. See Adjusting Tip Load Switch.
2.2 Adjusting Tip Load Switch
To verify that the tips have been loaded properly is the function of the tip load switch
(brass plunger) located in the front right corner of the pipetting head. As the disposable
tips are loaded, the tip jig makes contact with this plunger pushing it up, breaking the
connection in the switch. This indicates that the tips are loaded properly to the right
height.
This tip load switch needs to be perfectly adjusted for the correct operation. There is an
adjustment screw in the middle of the brass plunger. To adjust this screw, a 9/64” Allen
wrench is needed. You must hold the brass plunger stationary while you turn the
adjustment screw. The screw has a spring on it to keep tension on the screw threads
preventing vibration from altering the setting you have made.
If the distance between the top of the tip and the shuck plate is more than .062, you need
to turn the Allen wrench 1/2 turn, counter clockwise. If the tips are too tight to the shuck
plate, turn the Allen wrench 1/2 turn clockwise. In either situation, do not change this
setting more than1/2 turn, without retesting the tip load function.
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