philips CD player won't open drawer

[EvT]

Hi,

I have a philips AK601 CD player which will not open its drawer.
Before this the drawer would close immediately after opening, don't
know if this is part of the problem.

I found out that the motor which opens the door gets +5 volts
initially to close the door. After that it keeps getting +5 volts.
When I push the open/close button on the frontpanel the voltage drops
to about +2 volts. I think it should be a negative voltage to let the
motor run the other way to open the drawer.

What could be wrong?

Eelco.

 

[LASERandDVDfan]

I have a philips AK601 CD player which will not open its drawer.
Before this the drawer would close immediately after opening, don't
know if this is part of the problem.

Did you check the belt which drives the mechanism? Also check the condition of
the limit switches which tell the CD player's syscon whenever the drawer is
open or closed. - Reinhart

 

[EvT]

On 14 Apr 2004 03:39:41 GMT, laseranddvdfan@aol.com (LASERandDVDfan)
wrote:

I have a philips AK601 CD player which will not open its drawer.
Before this the drawer would close immediately after opening, don't
know if this is part of the problem.


Did you check the belt which drives the mechanism? Also check the condition of
the limit switches which tell the CD player's syscon whenever the drawer is
open or closed. - Reinhart

belt is ok (can keep motor still even with +5V over it)
Switch is ok too (one switch for open and closed detection)

It's the second part of my posting that is interesting...

I found out that the motor which opens the door gets +5 volts
initially to close the door. After that it keeps getting +5 volts.
When I push the open/close button on the frontpanel the voltage drops
to about +2 volts. I think it should be a negative voltage to let the
motor run the other way to open the drawer.

What could be wrong?

I found that the voltage drop is only for a second or so. Since I'm
using an analogue multi-meter for voltage testing, it is just not fast
enough to show the complete voltage drop.
during that second I can see the motor trying to run in the other
direction (the direction to open the drawer, or perhaps only loosen
tension on the belt after the +5V drops to a lower voltage, which
causes the axle of the motor to move a little)

When I manually push the drawer (partly) open immediately after the
voltagedrop, it seems the voltage is between 0 and +1 volts for about
4 seconds.
After that the voltage becomes +5V again, which causes the drawer to
close. When it is closed, the voltage stays +5V. (should be 0 I
think?)

Also I checked the voltage on another Philips (different model) CD
player. It gets -5V immediately after pressing the OPEN switch on the
front. This causes the motor to run in the other direction to open the
drawer.

The defective one just doesn't get the negative voltage.


Any ideas?

Eelco.

 

[LASERandDVDfan]

Are you sure the limit switch is good or that it has an uninterrupted
connection to the player electronics? Did you try measuring continuity of both
sides of the switch to determine it's condition? The continuity for each side
of the switch when closed must read infinity with no resistance. Also, are you
sure there's only one limit switch?

Another thing you could do is to trace the motor wiring and the open/close
control to specific traces on the player circuits. This might help you to find
parts that could be suspect on the circuit path that the parts are connected
to.

Also I checked the voltage on another Philips (different model) CD
player. It gets -5V immediately after pressing the OPEN switch on the
front. This causes the motor to run in the other direction to open the
drawer.

If this CD player uses the same chassis and possibly even similar electronics
despite being a different model, it is still possible that the functional
player might provide clues as to what is going on with the broken player.
Although schematics would still be most helpful, you can use parts from the
good player to compare the values of suspected parts on the bad player. -
Reinhart

 

[Mark D. Zacharias]

I have seen one Philips 5-disc model which gets 1 or 2 bad drive
transistors, mounted on the front panel pc board. Don't remember the model
number.

Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


<EvT> wrote in message news:78jq7054mb0vldjiameqocjb2sr690ru9t@4ax.com...

On 14 Apr 2004 03:39:41 GMT, laseranddvdfan@aol.com (LASERandDVDfan)
wrote:

I have a philips AK601 CD player which will not open its drawer.
Before this the drawer would close immediately after opening, don't
know if this is part of the problem.


Did you check the belt which drives the mechanism? Also check the
condition of
the limit switches which tell the CD player's syscon whenever the drawer
is
open or closed. - Reinhart

belt is ok (can keep motor still even with +5V over it)
Switch is ok too (one switch for open and closed detection)

It's the second part of my posting that is interesting...

I found out that the motor which opens the door gets +5 volts
initially to close the door. After that it keeps getting +5 volts.
When I push the open/close button on the frontpanel the voltage drops
to about +2 volts. I think it should be a negative voltage to let the
motor run the other way to open the drawer.

What could be wrong?

I found that the voltage drop is only for a second or so. Since I'm
using an analogue multi-meter for voltage testing, it is just not fast
enough to show the complete voltage drop.
during that second I can see the motor trying to run in the other
direction (the direction to open the drawer, or perhaps only loosen
tension on the belt after the +5V drops to a lower voltage, which
causes the axle of the motor to move a little)

When I manually push the drawer (partly) open immediately after the
voltagedrop, it seems the voltage is between 0 and +1 volts for about
4 seconds.
After that the voltage becomes +5V again, which causes the drawer to
close. When it is closed, the voltage stays +5V. (should be 0 I
think?)

Also I checked the voltage on another Philips (different model) CD
player. It gets -5V immediately after pressing the OPEN switch on the
front. This causes the motor to run in the other direction to open the
drawer.

The defective one just doesn't get the negative voltage.


Any ideas?

Eelco.

 

[EvT]

On 15 Apr 2004 03:13:25 GMT, laseranddvdfan@aol.com (LASERandDVDfan)
wrote:

Are you sure the limit switch is good or that it has an uninterrupted
connection to the player electronics? Did you try measuring continuity of both
sides of the switch to determine it's condition? The continuity for each side
of the switch when closed must read infinity with no resistance. Also, are you
sure there's only one limit switch?
Yes, measured continuity on both sides of the switch when pressed,

open when depressed. It's good.
And Yes, there is only one switch (and an ingeneous mechanical
mechanism to press it when the drawer is completely open or closed).
It is identical in both CD players.

Another thing you could do is to trace the motor wiring and the open/close
control to specific traces on the player circuits. This might help you to find
parts that could be suspect on the circuit path that the parts are connected
to.

Yes, good idea, will take me some time, but I'll try!

Also I checked the voltage on another Philips (different model) CD
player. It gets -5V immediately after pressing the OPEN switch on the
front. This causes the motor to run in the other direction to open the
drawer.

If this CD player uses the same chassis and possibly even similar electronics
despite being a different model, it is still possible that the functional
player might provide clues as to what is going on with the broken player.
Similar electronics would be smart for philips to design, so good

chance. I'll check that. The (lay-out of the) main boards of both
players are quite different, although.

Although schematics would still be most helpful, you can use parts from the
good player to compare the values of suspected parts on the bad player. -
Reinhart

Thanks a lot!
Eelco.