Maintenance; Adjustment - Furuno GP-90 Service Manual

3.1 Adjustment

Switching regulator frequency and +5 V are adjusted by R34 and R84 respectively as shown in Table
3.1.
Gate of Q16 and GND(R80)
See Fig.3.3 for
enlarged view.
J2
R84 (V - ADJ)
R34 (F - ADJ)
Table 3.1 Adjusters on NP board
Test points
J2#3(+) and J2#5(-)
Fig.3.1 NP Board (20P8188)
Fig.3.2 Power supply circuit, enlarged view (NP Board)

3. Maintenance

Adjuster Rating
R34 82.3 to 84.3 KHz
R84 5.07 V to 5.17 V
6
See Fig.3.2 for
enlarged view.
Q16 gate
Regulator, U8
Type : PQ09RA1
Code : 000-131-421
4A Fuse