JBL 6810, Field Service Manual

Page: 17 / 20

Chart 4
Symptom:
No Audio, No
Video
Check Tuner
Interface Voltage
Note: Before Video
And Audio Tests.
Check The Input'
Voltage To The IF
Module. If Vollage Is
Normal, Proceed
With The Cable
Tests.
Check Diode D18
C52.
Check Voltage At
TP15.
Replace
IF Module
Check R74. C52. 14
C53.
Charts
Symptom:
No Vertical
Deflection
Chart 6
Symptom:
Picture Rolls
Check Deflection
Panel TP17 45V
Source.
Check R81. CS7, D20
Check Deflection
Panel TP22.
Check Qf7,Q18,
R108, R107.
Check TP20 For
Sawtooth Signal.
Jumper H o r l i .
Oscillator Module
"Osc Sel" Pln».
Adjust L I .
Check H o r l j .
Oscillator I C 1 ,
Oscillator Coll L I ,
Or Replace Module.
Remove Jumper
From "Osc Set" Pins.
Horltontal
Oscillator OK.
Check H o r l i . Osc.
Module TP1 For
Video Signal
No
Replace Tuner
Yes
Check Vollage
Deflection Panel
Diode D18 Cathode.
Check IC3. R93,
C70. Horl/onlil
Oscillator Module
IC2 Or Replace
Module.
Check C72 015.
018. 0 1 B 0 r f l s p l . c e
Deflection Panel.
Check Yoke Inter-
connect And Plugs
C78.R117.RH8.
Vertical Sweep
Circuits OK.
Unplug Sync Cable
To I/O Panel J707.
Plug Cable Into
Jack Plate. Tuner
Video Out.
Check I/O Panel
Q28.R124.R125,
Or Replace I/O
Panel.
Check Horiz. Osc.
Module 0 1 , 0 2 , C4,
Or Replace Module.'
Check Sync Cable
From I/O Panel J707
To H o r l i . Oscillator
Module J302 Or
Replace I/O Panel.