Furuno FR-1500 MARK-3 Series Installation Manual page 53

5. Press the [ENTER/SELECT] key to automatically adjust the video level. When
the adjustment has been completed a beep sounds (R-type only).
6. Connect an oscilloscope to TP6 on the pcb 03P9230 display unit) and mea-
sure main bang signal level. It should be 4.0 Vpp ±0.2 V. If it is not, within that
range redo steps 4 and 5 above.
Manual adjustment
If the video signal level could not be adjusted automatically, adjust it manually as
follows.
1. Do steps 1-3 in automatic tuning.
2. Press the [4] key to select MAN from the VIDEO LVL field.
3. Press the [ENTER/SELECT] key.
4. Connect the oscilloscope to TP6 on the pcb 03P9230. Operate the EBL rotary
control while pressing and holding down the HL OFF control so the main bang
level is 4.0 Vpp ±0.2 V.
5-4
U92 (EEPOT)
TP6
(Video Signal)
Figure 5-6 pcb 03P9230
TP19 (TRIG)