Search Head Screen; Auto Balance - Thermo Scientific Apex Service Manual

Search Head
Screen

Auto Balance

Thermo Fisher Scientific
REC 4258 Rev C
1. Once balance is achieved at both frequencies, fit search head
screen, rotate top of Nylatch to secure.
2. Monitor tp 13 [High RF], adjust VR7 [LFX] and VR6 [LFR] for
minimum signal.
3. Set JP6 [Frequency select to High frequency operation.
4. Adjust VR5 [HFX] and VR4 [HFR] for minimum signal.
Once manually balanced (TP13 = 200 mV or less), the Auto-Balance
circuit can be enabled and tested.
1. Monitor TP13 [High RF], place ferrite in aperture to generate
offset signal 4 V pk-pk (approximately).
2. Set JP8 [A/B on/off] to auto balance on.
3. Check signal is automatically reduced by Auto Balance circuit
(typically less than 250 mV).
4. Remove ferrite from aperture.
5. Set JP6 [Frequency select] to Auto frequency operation.
6. Turn power supply off and disconnect.
Search Head PCBA Head Setup
1
Search Head PCBA Head Setup 1-11
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