There should be a sensor or switch somewhere in the drive mechanism that the drive uses to sense when the drive is closed or fully open. Perhaps that switch is damaged (if mechanical) or dirty.

Likewise, dust in the open/close button can cause erratic behaviour.

I have had problems with many CD and DVD trays not opening/closing, problem is wear of plastic parts and aging of lubrication, never sensors.

I had one that was doing something similar. Ended up being that some plastic bit had broken off inside the drive. I ended up trashing the drive because it broke even more when I was trying to figure out where the broken piece came from.

Cheap plastic plus grease just breaks those drives in some time. Especially if they have worked in a dusty enviroment in the past.

yawetaG wrote on 2020-09-15, 04:59:

There should be a sensor or switch somewhere in the drive mechanism that the drive uses to sense when the drive is closed or fully open. Perhaps that switch is damaged (if mechanical) or dirty.

Likewise, dust in the open/close button can cause erratic behaviour.

Hi, the sensor is there and it works correctly both ways, however the problem is that the tray opens until a bit before pressing the switch, so the drive never sees the tray as open and that's why it's closed again.

Cyberdyne wrote on 2020-09-15, 05:02:

I have had problems with many CD and DVD trays not opening/closing, problem is wear of plastic parts and aging of lubrication, never sensors.

I took a careful look at the plastic gears and rails on the drive and can't find any wear on them, they seem to be perfect: no missing/broken teeth on any gears or anything. I noticed the drive had no lubrication anywhere, which seemed odd so I added a bit of grease on the rails and gears but nothing changed.

cyclone3d wrote on 2020-09-15, 06:10:

I had one that was doing something similar. Ended up being that some plastic bit had broken off inside the drive. I ended up trashing the drive because it broke even more when I was trying to figure out where the broken piece came from.

Cyberdyne wrote on 2020-09-15, 06:29:

Cheap plastic plus grease just breaks those drives in some time. Especially if they have worked in a dusty enviroment in the past.

Well, I'm no plastics specialist, but quality here does not seem that cheap. It does not look that different from an ABS Lego piece, and those are high quality in my experience. Also, i can't find any broken pieces and I cleaned them already. Very strange this. I was thinking that maybe the motor had lost power due to aging, is that possible?

Or the circuit driving the motor isn't providing the required juice anymore.
You can test this by disconnecting it completely from the board and applying 5 volts from a suitable supply.

Or to rule out mechanical problems, manually extend the tray all the way. Does it go nicely until the end, or is there noticeable increased friction from the point where it tends to stop (before reaching the "tray open" sensor)?

quicknick wrote on 2020-09-15, 17:21:

Or the circuit driving the motor isn't providing the required juice anymore.
You can test this by disconnecting it completely from the board and applying 5 volts from a suitable supply.

Or to rule out mechanical problems, manually extend the tray all the way. Does it go nicely until the end, or is there noticeable increased friction from the point where it tends to stop (before reaching the "tray open" sensor)?

Thanks for the suggestion. I did the test, and applying 5V from the power supply directly to the motor (disconnected from the DVD drive board, of course) the drive opens and closes perfectly. It even does so very fast and with much force, so I think the problem does lie on the voltage (or power?) the motor is receiving from the DVD drive. Any ideas what I could look for now? the drive only has a few electrolytic capacitors, nothing else that I can see as "replaceable" but I do not even know if those capacitors have anything to do with the tray motor or not.

try oiling, also try cleaning the door so it doesn't stick on the bezel.

Aged, leaky shorting motors will put more strain on the motor IC driver which is sending out fixed voltage for smooth, controlled motion, and power droops slightly causing the drawer to not open properly. Like you said drawer opens violently using 5V juice, is what exactly that motor IC is for.

Back in the day, our techs and when I used to fix TVs when CRT glass bulb and spinning CD and DVD players is the king. Well, we would find the shorts in the commutator gaps would stop the cd player from spinning the disc then meant wouldn't play music or spin uncontrollably. Either clean out the conductive dirt in the commutator gaps (mechanical cleaning is only way, meant disassembly of the said motor), or replace with NEW motor or correct one, not used.

Even capacitors on that little board can be cantankerous.

I had seen a amp shut down intermittently with a leaky two wire cooling fan that used commutator motor (intermittent cooling on demand during loud music passages), a smart tech told the audio repair guy to replace that fan which fixed that. I had a large rear projection TV that used pair of ultra quiet (80mm computer type made by NONOISE brand) fans get little stickum when stopped, still look good, but not quite right, I did clean out the dust but still, and TV would shut down right after turning on. The fans were 2 wire only and TV has two current measuring circuits built into motherboard for the two fans. Flicked both fans into motion at same time and turn it on kept TV alive even fans are running on their own. Replaced both fans with new fixed that.

Cheers,

When I encountered this problem, one of the tiny gears turned out to be cracked. It was much more subtle than a missing tooth.

lubrication dried out and gears turning or sliding will cause this too. I'm talking about the gears that turns on the plastic round things, lube these with lithium grease made for plastic.

Cheers,