My work machine occasionally throws a wobbly.
It is doing it now - Opening and closing a DVD drive incessantly.
Is this a know bug?

Alan

--
Linux Mint 21.1 kernel version 5.15.0-91-generic Cinnamon 5.6.8
AMD Phenom II x4 955 CPU 16Gb Dram 2TB Barracuda

On 1/9/2024 12:42 PM, pinnerite wrote:
> My work machine occasionally throws a wobbly.
> It is doing it now - Opening and closing a DVD drive incessantly.
> Is this a know bug?
>
> Alan

https://forum.videohelp.com/threads/231592-Apex-DVD-player-has-disc-tray-that-keeps-opening-closing

"This is very common. It is caused by those who use that tapping to close the tray
rather than the button. There are gears which pull the tray out and in. After quite
a few manual pushes these gears become worn due to unequal pressure applied to the
tray. Another possibility is tray alignment caused by this same issue.

It can't be stressed enough. There is an Open/Close button for a reason. Use it
or you may end up with a tray that can't tell whether it's to be opened or closed.
"

The drive has a safety feature. If you leave your finger in the tray
path, the tray won't cut your finger off. The motor driver detects
excess current flow, indicating a jam, and it reverses the polarity
of the motor excitation. This is similar to how the door in an
elevator works, when a part of your anatomy is in the path and
it does not trip the optical detection. (Elevators have both optical
and electro-mechanical door safety features, and these are at different
heights in the design.)

Tray overcurrent works in both directions. The tray will reverse while
opening. Or it will reverse while closing. And it happens if anything gets
in the path and causes the motor current to increase too much.

There should also be limit switches, which detect when the
tray is fully open and when the tray is fully closed. The
motor drive current should be turned off, as soon as a limit
switch closes (because if closure is *not* detected, the
damn tray will overcurrent, then reverse and open again).

Don't ask me what the logic equations are that govern behavior.
There's a smart way to do it, and a stupid way to do it.

The issue could be related to drive power (+5V on a laptop,
or +5V and +12V on a desktop). Check that not too many electrical
loads are off the same peripheral power chain. More than once,
I've had to "rebalance" the electrical loads, when, for example,
I put too many hard drives on the same chain. Hard drives will
spin down, then spin up again, when power is marginal (too low).
(Drives have their own "Power-Good" detection onboard. >+11V
for the motor.)

A brand new hard drive I got, it was "clicking" when I first got it,
and it turned out the power requirements for the drive,
have tightened up requiring a more precise +5V and +12V.
Once I re-did the cabling, the clicking stopped. Eventually,
the power supply was replaced (that is the ATX supply that was
getting "tired" from being beaten up by a high power CPU).
During these incidents, the DVD tray had "no comment" on the
matter, and it was not reacting in any way.

I would suspect then, you've been pushing the tray with
your thumb, once too often. And now those shitty plastic
gears are worn. The tray, gears and other fiddly bits,
are apparently manufactured in a large central factory,
and the material cost is around $1. Multiple DVD drive
companies may buy millions of units, from that factory,
for their housings. Then, a custom fascia may be fitted to
the tray, to "personalize" the design. The drive companies
do not generally make all their own housing parts. The
controller board, on the other hand, is made in-house,
and using a "favored" chipset. One company likes Panasonic
chips, another likes MediaTek. At least half the value
of the design, is quality firmware. Burning DVDs is hard work.

Paul

On 09/01/2024 17:42, pinnerite wrote:
> My work machine occasionally throws a wobbly.
> It is doing it now - Opening and closing a DVD drive incessantly.
> Is this a know bug?
>
> Alan
>

In earlier times I heard that it was a sure and certain sign that you
had foolishly allowed a Trojan Virus to install itself on your PC and
that a criminal mastermind who had taken control of your drives was
diligently searching them for I forget what, something or other.

Reality may be a little less interesting.

TW

On Tue, 9 Jan 2024 19:42:03 -0500
Paul <nospam@needed.invalid> wrote:

> On 1/9/2024 12:42 PM, pinnerite wrote:
> > My work machine occasionally throws a wobbly.
> > It is doing it now - Opening and closing a DVD drive incessantly.
> > Is this a know bug?
> >
> > Alan
>
> https://forum.videohelp.com/threads/231592-Apex-DVD-player-has-disc-tray-that-keeps-opening-closing
>
> "This is very common. It is caused by those who use that tapping to close the tray
> rather than the button. There are gears which pull the tray out and in. After quite
> a few manual pushes these gears become worn due to unequal pressure applied to the
> tray. Another possibility is tray alignment caused by this same issue.
>
> It can't be stressed enough. There is an Open/Close button for a reason. Use it
> or you may end up with a tray that can't tell whether it's to be opened or closed.
> "
>
> The drive has a safety feature. If you leave your finger in the tray
> path, the tray won't cut your finger off. The motor driver detects
> excess current flow, indicating a jam, and it reverses the polarity
> of the motor excitation. This is similar to how the door in an
> elevator works, when a part of your anatomy is in the path and
> it does not trip the optical detection. (Elevators have both optical
> and electro-mechanical door safety features, and these are at different
> heights in the design.)
>
> Tray overcurrent works in both directions. The tray will reverse while
> opening. Or it will reverse while closing. And it happens if anything gets
> in the path and causes the motor current to increase too much.
>
> There should also be limit switches, which detect when the
> tray is fully open and when the tray is fully closed. The
> motor drive current should be turned off, as soon as a limit
> switch closes (because if closure is *not* detected, the
> damn tray will overcurrent, then reverse and open again).
>
> Don't ask me what the logic equations are that govern behavior.
> There's a smart way to do it, and a stupid way to do it.
>
> The issue could be related to drive power (+5V on a laptop,
> or +5V and +12V on a desktop). Check that not too many electrical
> loads are off the same peripheral power chain. More than once,
> I've had to "rebalance" the electrical loads, when, for example,
> I put too many hard drives on the same chain. Hard drives will
> spin down, then spin up again, when power is marginal (too low).
> (Drives have their own "Power-Good" detection onboard. >+11V
> for the motor.)
>
> A brand new hard drive I got, it was "clicking" when I first got it,
> and it turned out the power requirements for the drive,
> have tightened up requiring a more precise +5V and +12V.
> Once I re-did the cabling, the clicking stopped. Eventually,
> the power supply was replaced (that is the ATX supply that was
> getting "tired" from being beaten up by a high power CPU).
> During these incidents, the DVD tray had "no comment" on the
> matter, and it was not reacting in any way.
>
> I would suspect then, you've been pushing the tray with
> your thumb, once too often. And now those shitty plastic
> gears are worn. The tray, gears and other fiddly bits,
> are apparently manufactured in a large central factory,
> and the material cost is around $1. Multiple DVD drive
> companies may buy millions of units, from that factory,
> for their housings. Then, a custom fascia may be fitted to
> the tray, to "personalize" the design. The drive companies
> do not generally make all their own housing parts. The
> controller board, on the other hand, is made in-house,
> and using a "favored" chipset. One company likes Panasonic
> chips, another likes MediaTek. At least half the value
> of the design, is quality firmware. Burning DVDs is hard work.
>
> Paul

This an old system (16 years) so this is odd behaviour.
Today, mthe drive has opened and remains there.
Much quieter thankfully.

Alan

--
Linux Mint 21.1 kernel version 5.15.0-91-generic Cinnamon 5.6.8
AMD Phenom II x4 955 CPU 16Gb Dram 2TB Barracuda