NAD T531B - Μ-Com Circuit

3-3
Replace IC506.
Refer to Front Part
Check short
Reconnect it.
2. µ-COM Circuit
A. No Power
Does Logo appear
on the screen?
Is oscillation of
X501 normal?
Are IC503 Pins 14, 288
and 29 normal?
Does no DISC appear?
Does Hello
appear at FLD?
Is P5901
connected normally?
Is P5901 Pin 23 normal?
The
waveform on A[00:21]
and D[00:15] of IC501
normal?
Are IC506 Pins 7, 8 normal?
Replace Main B/D.
Check the oscillation
Check short.
OK
Replace IC501
or IC503.
Check power.
(Refer to power)
If power is
normal
OK
POWER ON
1
1
YES
YES
YES
YES
YES
YES
YES
YES
A
NO
NO
NO
NO
NO
NO
NO
NONO
NO
A