Loma IQ2 Service Manual page 94

RECOMMENDED TEST EQUIPMENT
Dual Beam Oscilloscope, 100 MHz bandwidth minimum.
x1 probe
3.5 Digit - Digital Multimeter (DMM).
Static safe wrist strap
Plastic trim tool
Penlight/flashlight
WARNING
Before commencing any test work ensure that you are wearing a
correctly grounded wrist strap.
BALANCE (single & dual frequency detectors)
The detector uses a pair of equally spaced receiver coils located within the
search head case. The signals received by the coils when the detector is in its
normal state, i.e. no product or metal present should be sinusoidal at a value of
less than 1V peak to peak. If the detector is of a dual frequency type then the
balance will require checking and adjusting if necessary for each operating
frequency. In the unlikely event of the balance value increasing beyond this
point, which a gradual loss of metal sensitivity or an increase of product effect
may indicate. The balance can be checked and adjusted as follows:
NOTE
No metal or product should be present in the aperture whilst this check is
in progress.
1. Using the 5mm allen key supplied with your equipment, unscrew the 2 front
hinged door screws on the control box and open the door.
2. Select an unused product memory position and set the "Head power" to
"MAX".
3. If the detector is a dual frequency type then initially select HIGH for the
frequency menu position in the product memory chosen.
4. Remove the balance ground link from JP9 on the control board.
5. Connect the oscilloscope via a x1 probe to TP11 shown highlighted in
on page 1
hex pillar.
Module 9095
; connect the probe earth clip to the adjacent control board mounting
Functional Testing
Figure 1
7-2