TROUBLESHOOTINGTROUBLESHOOTING
2. SYSTEM CIRCUIT
B-1. Bad playback quality (1)
A. LED DISPLAY
Noise appears on the
playback screen.
No LED display.
Is noise diminished by trackingNO
Re-adjust PATH.
Is 5V obtained at IC701 NOadjustment.
pin #9, 25?Check R588, D857, L503, L860
YES
YES
Noise band is trembled up andNONoise appears on the screen evenYES
NOdown?though changing tape.Re-adjust PATH.
Oscillation at IC701pin #1? Exchange IC701.
YES
YES
Is there CTL pulse at IC501NOIs the height of CTL HEAD normal? NORe-adjust the height of AC HEAD.
pin#97?No dust?Remove the dust.
Specific GRID/SEG doesnt function.
YES
YES
Is there problem in CTL InputYESCheck C510,R545~R547
Check IC501.IC 501 pin #91, 92, 98.
NOcircuit and amplifier.Check IC 701 pin #22~24, 27,
GRID output at PORT of IC701?
28, 30, 31.
YES
NOB-2. Bad playback quality (2)
SEGoutput at PORT of IC701?Check IC 701 pin #10~12, 14~21.
Noise appears on the FullRecheck step B-1
playback screen.(Bad playback quallty (1)).
YES
Exchange IC701.
NOAre there SW, HA SW pulse atNO
Are SW pulse and HA SW normal?Check IC501.
IC501 pin #16, 18?
YES
YES
Check PCB Pattern.
NOCheck HEAD AMP connector
ENVE Wave at PT01 pin #4?
and HEAD.
YES
Check VIDEO circuit.
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ACEC
