Moving right along to a charming Denon 650f

[nylicens]

Finally finished the 1604. Sound guys haven't yet had chance to OK the fix, but I'm keeping my fingers crossed.

I am now looking at a Denon rack mount CD player. Will not open door. So popped cover and it looks like it might spin the cd as it tries when I hit the lock tab. Finally yanked whole cd tray unit and ran the tray motor from the pc board plug. It "seems" to be working fine. So checked the Denon site but couldn't find anything. If someone has a schematic or previous experience I'd appreciate a pointer.

[nylicens]

...checked the Denon site but couldn't find anything. If someone has a schematic or previous experience I'd appreciate a pointer.

Well I just called Denon Pro support and they said the schematic was private information and they would not supply it. Wow, pretty amazing!!


And this is "Professional" equipment?? Or am I just overreacting?

[eschertron]

I've got a CD player in a computer that exhibits the same (or similar) symptoms. What I've found is that if there is media in the carrier, then the tray opens just fine. Must have something to do with how the unit detects a jam? I haven't gone any farther because the player is certainly *not* pro grade, and is not worth my time to troubleshoot. Try the 'media present' trick to see if makes a difference. May lead you to a resolution of your problem?

[nylicens]

(snip)Try the 'media present' trick to see if makes a difference. May lead you to a resolution of your problem?

It doesn't seem to matter in this instance. The tray opens fine if I run the motor directly from the plug from the main circuit board with or without a cd.

[Jazz P Bass]

Most CD players have a gear that drops the spindle when the unit is calling for door open.
Sometimes the gear gets out of sync.
So the first thing to check: is the tray motor getting the voltage it needs?
With the unit on the bench, you can manually run the tray motor with a 9 volt battery.
(Reverse the polarity to close.)

[nylicens]

Well I just called Denon Pro support and they said the schematic was private information and they would not supply it. Wow, pretty amazing!! And this is "Professional" equipment?? Or am I just overreacting?

When I called Denon support and was given the answer about not supplying schematics, I asked to be connected to a manager. I left a voice mail msg detailing my unhappiness with Denon. The Manager just called back and sent me a PDF of the schematic. So at least I now have the schematic.

[Audiotexan]

It doesn't seem to matter in this instance. The tray opens fine if I run the motor directly from the plug from the main circuit board with or without a cd.

IME, when I've seen this, quite often I've had to do a complete realignment of the loading gears thanks to someone with happy hands 'forcing' the tray back in (which ended up causing the gears to jump a tooth and puts the whole thing out of alignment).

One of the points that I always strongly make to the owner of a post realignment unit is: DO NOT push the tray in, or pull it out. USE THE ^#%%^$# BUTTON!!! >.<

[Jazz P Bass]

DJ's are good at putting stuff in front of the tray.

Tray comes out, stops short, jumps a tooth.

[nylicens]

DJ's are good at putting stuff in front of the tray.
Tray comes out, stops short, jumps a tooth.

That doesn't seem to be the case here. The unit was installed at chest height in a rack, and when I pull out the tray and run the tray motor by itself, (open and closed) the open/closed switch seems to be working ok. Actually the unit seems to close ok, it's just the opening that doesn't work. I'll have to look at the inputs to the motor driver and see if they're ok there. If they are, I may just try and jury rig another driver for the motor.

[Fragger]

?
How to Fix a stuck CD Tray - YouTube

[Audiotexan]

That doesn't seem to be the case here. The unit was installed at chest height in a rack, and when I pull out the tray and run the tray motor by itself, (open and closed) the open/closed switch seems to be working ok. Actually the unit seems to close ok, it's just the opening that doesn't work. I'll have to look at the inputs to the motor driver and see if they're ok there. If they are, I may just try and jury rig another driver for the motor.

Again though, I've seen alignments shifted in such a manner that you can actually get it in a closed position, hit the button, and it opens...but it won't close. And vice versa.

I'm still betting that it's an alignment issue.

It's exceedingly rare that if the motor's strong, and the switches are working, that it's anything else. Not impossible, but *rare*. Especially the more light sensors/switches there are. But again, that's just been my experience. *shrugs*
I've seen the sensing lamps die, or bad switches, and weak motors...but you don't seem to have that (at least from indications so far).

[Audiotexan]

?
How to Fix a stuck CD Tray - YouTube

Weak belts are another good cause (if it's not a "direct ic drive" motor)

[nylicens]

Again though, I've seen alignments shifted in such a manner that you can actually get it in a closed position, hit the button, and it opens...but it won't close. And vice versa.

I'm still betting that it's an alignment issue.

It's exceedingly rare that if the motor's strong, and the switches are working, that it's anything else. Not impossible, but *rare*. Especially the more light sensors/switches there are. But again, that's just been my experience. *shrugs*
I've seen the sensing lamps die, or bad switches, and weak motors...but you don't seem to have that (at least from indications so far).

Turns out it was really simple. The open/close button was inop.

[nylicens]

... Actually the unit seems to close ok, it's just the opening that doesn't work. I'll have to look at the inputs to the motor driver and see if they're ok there. ...

The inputs weren't ok. There was no change at the motor amp when the open/close button was actuated. Checking some forums on Denon I noted there were many complaints re: buttons. Checked and that was it. R&R'd the open/close membrane button on the pcb and it all works fine now. The button I replaced it with has loud click when operated, unlike the OEM which are dead silent in operation.

[nylicens]

Weak belts are another good cause (if it's not a "direct ic drive" motor)

This Denon unit was interesting in that it had a single tray motor and a single belt drive from that so any blockage simply stopped the tray load or unload.