Harman Kardon HD7725 - Troubleshooting

HD7725
Troubleshooting
When a problem occurres, first check the pick-up lens for dirt and each connector for tight and secure connection.
If the problem persists after checking both of these items, use the following check procedures.
Power switch is ON
- NO rar
YES
NO
Does the tray open?
Does the Yrs no |
YES
| @ Check the tray drive circuit.
NO
Is initial read executed? @ Check the tray drive circuit.
@ Check the focus circuit.
@ Check the disc.
® Check the tracking servo circuit.
NO
Is playback executed?
YES
Is audio output produced?
YES
OK
(1) When Multi Display fails to light properly.
Power switch ON (without disc)
@ Check the audio circuit.
Is "1" displayed when the PLAY
button is pressed?
Check the power circuit for
proper voltage.
Are reset circuits for 10102, NO Reset circuit defective,
1C201 and IC401 in good Q55 and peripheral circuit
condition
(when Q55 opertating properly)?
4?
SW ON Some 10m sec.
v YES
NO F
Is the oscillating circuit of IC401 Ls, | X601, 1C201, IC601 defective.
in good condition? Check pin 28
4.23MHz
'¢——>' About 0.24m sec.
YES
NO | 10401 defective
Is a scanning signal output from
C401? Pins 41-47
Y YES
Multi display FL401 defective
-25V