Loma IQ2 Service Manual page 95

JP9 link
Figure 1 Exploded View of JP9, TP11 and Earthing Pillar
6. Adjust the oscilloscope time base until a sine wave can be seen and the
volts per centimetre to a setting of 50 mV.
7. When reading the amplitude from the oscilloscope multiply the reading by
a factor of 10, this is because the search headboard contains a x10
multiplier on the remote balance check line.
- For example: If the reading was 80mV peak to peak then the
balance value is actually 800mV peak to peak.
8. If the reading is greater than 100mV peak to peak then the balance
should be adjusted.
9. Remove the screwed bung in removable end plate on the rear of the
search head case. If the detector is a dual frequency type then remove
both screwed bungs. High frequency balance adjustment is through the
left-hand access hole.
10. Using the non - metallic trim tool inserted into the ferrite core immediately
below the access hole, a small penlight/flashlight may be of assistance in
locating the core. Adjust the core until the reading is as small as it will go.
11. If the balance cannot be adjusted to 100mV or below then contact your
local Group Service Centre for help.
12. To check the second balance for dual frequency types then change the
frequency selection to LOW in the frequency menu position for the
product memory chosen. Low frequency balance adjustment is through
the right-hand access hole.
13. Carefully withdraw the trim tool and refit all removed parts. Ensure the
screwed bung/s are fully tightened.
14. Replace the ground link at JP9
Module 9095
PL1
TP11
Earthing
pillar
Functional Testing
7-3