Sharp HT-M700 DVD player - need help with pickup not driven...

[Emanuele Girlando]

Inserting disks you obtain "READING" message for a long time. Then "NO
DISK".

Inside inspection (as per FAQ):
the spindle motor correctly runs.
Sled doesn't move unless you manually move it to a different location;
it correctly comes back to the original position. It is correctly
driven.
Neither attempt to focus nor laser light up are performed (dead
pickup).
Removed/cleaned/remounted the pickup flat cable: no change.
The lens servo works if manually powered (lens goes up and down)
The laser lights up if manually powered.
Power supply voltages are as per onboard indications.

Seems a problem with the pickup driver circuitry.
I published a snapshot of the main board @ http://www.qsl.net/iw1dhi/pickup-driver.JPG.
Any idea about what to check further? Any information about test
points?
Any picofuse around??

Thanks in advance.
Emanuele.

 

[Emanuele Girlando]

Inserting disks you obtain "READING" message for a long time. Then "NO
DISK".

Inside inspection (as per FAQ):
the spindle motor correctly runs.
Sled doesn't move unless you manually move it to a different location;
it correctly comes back to the original position. It is correctly
driven.
Neither attempt to focus nor laser light up are performed (dead
pickup).
Removed/cleaned/remounted the pickup flat cable: no change.
The lens servo works if manually powered (lens goes up and down)
The laser lights up if manually powered.
Power supply voltages are as per onboard indications.

Seems a problem with the pickup driver circuitry.
I published a snapshot of the main board @http://www.qsl.net/iw1dhi/pickup-driver.JPG.
Any idea about what to check further? Any information about test
points?
Any picofuse around??

Thanks in advance.
Emanuele.

nobody out there ??

 

[Franc Zabkar]

Inserting disks you obtain "READING" message for a long time. Then "NO
DISK".

Inside inspection (as per FAQ):
the spindle motor correctly runs.
Sled doesn't move unless you manually move it to a different location;
it correctly comes back to the original position. It is correctly
driven.
Neither attempt to focus nor laser light up are performed (dead
pickup).
Removed/cleaned/remounted the pickup flat cable: no change.
The lens servo works if manually powered (lens goes up and down)
The laser lights up if manually powered.
Power supply voltages are as per onboard indications.

Seems a problem with the pickup driver circuitry.
I published a snapshot of the main board @ http://www.qsl.net/iw1dhi/pickup-driver.JPG.
Any idea about what to check further? Any information about test
points?
Any picofuse around??

Thanks in advance.
Emanuele.

I don't know anything about your model, but I'd check the AM5868S
driver IC. There is an application circuit in this datasheet:
http://www.amtek-semi.com/files/AM5868.pdf

Verify the inputs coming from the uP and check Vcc1 and Vcc2.

I'd also look for a tray-in/tray-out switch at one of the connectors.

- Franc Zabkar

 

[Emanuele Girlando]

I don't know anything about your model, but I'd check the AM5868S
driver IC. There is an application circuit in this datasheet:
http://www.amtek-semi.com/files/AM5868.pdf

Verify the inputs coming from the uP and check Vcc1 and Vcc2.

I'd also look for a tray-in/tray-out switch at one of the connectors.

- Franc Zabkar

Franc,
Vcc1 and Vcc2 are both at 5V. Specs call for +12V at pin8 (Vcc1) ...
but it is connected to power supply +5V .. so I assume it is correct.
Mute (pin28) is down to 0.37V in normal conditions. It rises at +2.2V
during attempts to read disks. Sounds good.

I'll further investigate tomorrow.
Thank you very much for your support.