"Suddenly" get the floating Message "Check cable connection"

Post by pyotr filipivich
I was having problems with a Samsung monitor, so I just unplugged it,
and plugged in the spare. (I knew I'd find a use for it eventually!)
Only now, when the computer goes to sleep, or powers off the monitors,
the floating window shows up complaining about "loss of signal, check
cable connections". It is an annoyance more than anything else, but
I'm wondering because the previous monitor did not do that.
Both are make and model. "Sychmaster 932BW/ plus (Digital)" while
the problem child has the Analog connection.
So what I'm wondering is if anyone has a quick analysis of why this
time it is doing something different, or should I just chalk it up the
one of The Great Mysteries of the Universe"

The OSD does the detection. (That's a processor and firmware that
look at the refresh rate info, to see whether it is within panel spec
or not. The processor and firmware also have crude comms graphics
capabilities, for communication with the user. "Out of Range" should
be an old favorite by now.)

I have an Acer monitor that does that.
but it eventually gets tired of putting up
an OSD toast, and it goes to sleep and flashes
a blue LED at a low rate. Which is comforting I
guess, if you like blue LEDs.

Try walking the OSD menus and see if there is a preference
for stuff like that. You may find other horrors in there,
such as "Demo Mode". even my microwave oven has "Demo Mode",
and these are functions you don't really want to trigger.

The buttons on my monitor were placed in an inconvenient location
and it can even be hard to figure out where the damn power button
is for the thing. It should be the "last button" at one end of the
row of buttons. They can't seem to be bothered with tactile details
(shape the buttons so you know which is which).

Paul

J. P. Gilliver

2023-11-21 10:21:39 UTC

[]

Post by Paul
Try walking the OSD menus and see if there is a preference

[]
Another thought that occurs to me - given that they're (nominally!) the
same model: could be a signal wire in the lead - and/or pin in the plug
- that's broken or missing, that wasn't in the one that died. (I'm
assuming a normal "VGA" plug - like a 9-pin serial plug [like a serial
mouse], but with 15 positions, though usually not all present - rather
than separate RGB [and possibly sync.] BNC plugs.)

--
J. P. Gilliver. UMRA: 1960/<1985 MB++G()AL-IS-Ch++(p)***@T+H+Sh0!:`)DNAf

science is not intended to be foolproof. Science is about crawling toward the
truth over time. - Scott Adams, 2015-2-2

Paul

2023-11-21 11:53:34 UTC

[]

Post by Paul
Try walking the OSD menus and see if there is a preference

[]
Another thought that occurs to me - given that they're (nominally!) the same model: could be a signal wire in the lead - and/or pin in the plug - that's broken or missing, that wasn't in the one that died. (I'm assuming a normal "VGA" plug - like a 9-pin serial plug [like a serial mouse], but with 15 positions, though usually not all present - rather than separate RGB [and possibly sync.] BNC plugs.)

As far as I know, Loss Of Signal is loss of activity (transitions) on
the active bits used for video.

There is sync on green. Which means, to check for a loss of signal there,
you'd need to find "sync tips" or blacker than black downward spikes on the
green signal, as a sync indication. If none of R,G,B transitioned below 0V,
then there is no hidden sync. Sync on green is a miserable method, and
is no longer common, and the quality (green tint to screen) never made it
particularly acceptable. But if you see no activity at all on HSync and
VSync, then you're required to look for sync tips on green, and a composite
sync signal there.

If both HSYNC and VSYNC stopped transitioning, that might be a Loss Of Signal.
And that happens, when the drive is disabled on the outputs.

If only one of the two signals stopped transitioning, that's probably
"Out of Range", as zero is below the minimum.

That is VGA.

An HDMI signal, is decoded to produce a "Display Enable" signal. And it
is logic 1 during horizontal lines of pixels, and logic 0 during flyback
interval, during front or back porch. That signal, in turn, can be
decomposed into a HSYNC and VSYNC, if such is needed inside the monitor.
You would likely have to remove drive entirely on HDMI, to cause a loss
of signal, as the signal has to be there to extract DE. And the decomposed
DE, would be useful for the OSD frequency measurements (which determine
Out Of Range or not).

To me, the most likely explanation, is the video card is not driving an output
signal at the moment. which kills HSYNC and VSYNC. And RGB are at zero volts,
and there are no transitions below zero volts.

There's no particular reason the monitor should be measuring impedance.
That's the job of the video card, is to detect the presence of a cable,
by some means. and by making a "fake" VGA connector here, they can tell
a monitor is connected on VGA, if there are 75 ohm resistors on R, G, and B.
I've not seen a description of a "preferred method" for doing that
(impedance measurement).

(On audio cables, they use an AC coupled method for detecting device
types. The audio chip generates a 25KHz signal, and measures an AC current
flow, and this handles the issue caused by all the HDAudio inputs and outputs
being isolated with coupling caps. You can use two computers to check for this,
and I used a second computer with the audio sampling running at the max rate,
to detect the presence of the 25Khz signal. "Which must piss off the dog."
A description somewhere, claimed the impedance measurement was done quickly,
like in a millisecond. What I found using the second computer, is a stimulus
was on the cable for closer to one second. At least, it wasn't a millisecond
measurement.)

Paul

J. P. Gilliver

2023-11-21 14:11:27 UTC

Post by J. P. Gilliver

[]

Post by Paul
Try walking the OSD menus and see if there is a preference

[]
Another thought that occurs to me - given that they're (nominally!)
the same model: could be a signal wire in the lead - and/or pin in the
plug - that's broken or missing, that wasn't in the one that died.
(I'm assuming a normal "VGA" plug - like a 9-pin serial plug [like a
serial mouse], but with 15 positions, though usually not all present -
rather than separate RGB [and possibly sync.] BNC plugs.)

As far as I know, Loss Of Signal is loss of activity (transitions) on
the active bits used for video.

I wondered if there was some other detection - such as, maybe, if 5V is
still present, the monitor might just blank, not display the error
message, as it would know the lead hasn't fallen out. Especially as it
is nominally the same model of monitor, but the OP didn't get the
message with the other one. Though as has been suggested that might be a
non-volatile menu setting.

Post by Paul
There is sync on green. Which means, to check for a loss of signal there,
you'd need to find "sync tips" or blacker than black downward spikes on the
green signal, as a sync indication. If none of R,G,B transitioned below 0V,

I've not come across a -ve signal: usually peak white is (say) 1V, and
black is 0.3V, with sync 0V (or a shade above).

Post by Paul
then there is no hidden sync. Sync on green is a miserable method, and
is no longer common, and the quality (green tint to screen) never made it
particularly acceptable. But if you see no activity at all on HSync and
VSync, then you're required to look for sync tips on green, and a composite
sync signal there.

I can't see why sync on green ought to produce a green tint, but if the
sync signals are there, that's probably better.

Post by Paul
If both HSYNC and VSYNC stopped transitioning, that might be a Loss Of Signal.
And that happens, when the drive is disabled on the outputs.
If only one of the two signals stopped transitioning, that's probably
"Out of Range", as zero is below the minimum.
That is VGA.

I suspect the monitor in question is VGA (or variant) rather than HDMI.

Post by Paul
An HDMI signal, is decoded to produce a "Display Enable" signal. And it
is logic 1 during horizontal lines of pixels, and logic 0 during flyback
interval, during front or back porch. That signal, in turn, can be
decomposed into a HSYNC and VSYNC, if such is needed inside the monitor.
You would likely have to remove drive entirely on HDMI, to cause a loss
of signal, as the signal has to be there to extract DE. And the decomposed
DE, would be useful for the OSD frequency measurements (which determine
Out Of Range or not).
To me, the most likely explanation, is the video card is not driving an output
signal at the moment. which kills HSYNC and VSYNC. And RGB are at zero volts,
and there are no transitions below zero volts.

Agreed, or something like that. But the puzzle remains, why is he
getting the message now but not with the previous nominally-same
monitor. NV menu setting seems most likely, but if it's a captive lead
as you used to get especially with smaller monitors, a broken wire/pin
is possible.

Post by Paul
There's no particular reason the monitor should be measuring impedance.
That's the job of the video card, is to detect the presence of a cable,
by some means. and by making a "fake" VGA connector here, they can tell
a monitor is connected on VGA, if there are 75 ohm resistors on R, G, and B.
I've not seen a description of a "preferred method" for doing that
(impedance measurement).
(On audio cables, they use an AC coupled method for detecting device
types. The audio chip generates a 25KHz signal, and measures an AC current
flow, and this handles the issue caused by all the HDAudio inputs and outputs
being isolated with coupling caps. You can use two computers to check for this,
and I used a second computer with the audio sampling running at the max rate,
to detect the presence of the 25Khz signal. "Which must piss off the dog."
A description somewhere, claimed the impedance measurement was done quickly,
like in a millisecond. What I found using the second computer, is a stimulus
was on the cable for closer to one second. At least, it wasn't a millisecond
measurement.)

That's presumably the way they implement those audio arrangements that
let dim users plug things into the wrong sockets. (Which are a pain for
visually-handicapped folk, as the readout of what's plugged into what is
invariably graphical, often only.)

Post by Paul
Paul

John

--
J. P. Gilliver. UMRA: 1960/<1985 MB++G()AL-IS-Ch++(p)***@T+H+Sh0!:`)DNAf

Radio 4 is one of the reasons being British is good. It's not a subset of
Britain - it's almost as if Britain is a subset of Radio 4. - Stephen Fry, in
Radio Times, 7-13 June, 2003.

Paul

2023-11-21 17:17:13 UTC

That's presumably the way they implement those audio arrangements that let dim
users plug things into the wrong sockets. (Which are a pain for visually-handicapped
folk, as the readout of what's plugged into what is invariably graphical, often only.)

The newer audio interfaces on computers, have five black connectors and one red connector.

What this means for me, is LineOut goes to the red connector, and we haven't
the foggiest clue what goes into the five black connectors :-) Maybe the five
black connectors are for the optional towel rack.

It's a discover-able interface.

With a multimeter perhaps :-) In a dark room.

Maybe the five black connectors aren't connected to anything ?

It means you can't throw out the motherboard manual.

I am afraid to open that page of the manual, for what I might find for instructions.

<manual> "Look, you're an idiot, if you can't figure this out. There are five black
connectors. Four of the connectors have a bullet in them. Now, spin the
chamber... "

You cannot afford to be dim these days.

Suffice to say, the PC hasn't had a microphone attached yet.

Paul

pyotr filipivich

2023-11-22 15:32:10 UTC

The OSD does the detection. (That's a processor and firmware that
look at the refresh rate info, to see whether it is within panel spec
or not. The processor and firmware also have crude comms graphics
capabilities, for communication with the user. "Out of Range" should
be an old favorite by now.)
I have an Acer monitor that does that.
but it eventually gets tired of putting up
an OSD toast, and it goes to sleep and flashes
a blue LED at a low rate. Which is comforting I
guess, if you like blue LEDs.
Try walking the OSD menus and see if there is a preference
for stuff like that. You may find other horrors in there,
such as "Demo Mode". even my microwave oven has "Demo Mode",
and these are functions you don't really want to trigger.
The buttons on my monitor were placed in an inconvenient location
and it can even be hard to figure out where the damn power button
is for the thing. It should be the "last button" at one end of the
row of buttons. They can't seem to be bothered with tactile details
(shape the buttons so you know which is which).

The buttons for mine are under the monitor, right where you can
hit them when reaching under it. They are labeled - light grey on
black (so they do not distract you by being readable.0.

Post by Paul
Paul

--
pyotr filipivich
This Week's Panel: Us & Them - Eliminating Them.
Next Month's Panel: Having eliminated the old Them(tm)
Selecting who insufficiently Woke(tm) as to serve as the new Them(tm)

VanguardLH

2023-11-28 05:15:21 UTC

Unless the monitor has an all-black sense of when the monitor is
unpowered (by the video card losing power or no video output) will the
monitor know it is to power down. No RGB signals could be an all-black
screen, but not always represent power off by the video card.

DVI and HDMI have a 5V signal line. When it goes low (the video card
drops power) then the monitor knows it should power off. RGB has no
voltage signal. VGA has a sync signal, and the monitor might try to use
that to determine when the video card is powered off. With RGB, the
monitor has to guess when the video source is black (no source or dead
source would require the monitor show something, since that condition
would also be when you have not attached the cable to a video card).
However, the manual for your monitor says it has an RGB port, not a VGA
port. The 15-pin RGB port might not have the extra pins of a VGA port
to support Display Data Channel. Or the VGA port is so old that it
doesn't have pins for the DDC, and instead uses the extra pins for
identifying the monitor.

https://en.wikipedia.org/wiki/Display_Data_Channel

Don't know what video card you have. Don't know what type of RGB/VGA
cable you used. Don't know if the monitor's "RGB" labelled port is just
RGB or VGA, and if VGA if using DDC instead of extended ID. Looks like
that monitor came out around 2006, or earlier.

Since you switched from digital to analog video input on the replacement
monitor, you may have to go into BIOS to the Video Off Method (or
whatever it is called in your BIOS) to enable DPMS mode on the monitor.

https://www.tomshardware.com/reviews/bios-beginners,1126-8.html

Why did you switch from DVI to RGB for the replacement monitor? You say
the brand and models were the same for original and replacement
monitors, so why did you change from DVI (digital) to RGB (analog)
cabling? Seems you'd want to stick with DVI instead of go analog.

When you go into Device Manager, is your monitor shown as the model you
have, or some generic model? Same for going into Display settings: is
your brand and model listed, or a generic monitor?

J. P. Gilliver

2023-11-28 09:03:53 UTC

[]

Post by VanguardLH
Since you switched from digital to analog video input on the replacement
monitor, you may have to go into BIOS to the Video Off Method (or
whatever it is called in your BIOS) to enable DPMS mode on the monitor.

[]

Post by VanguardLH
Why did you switch from DVI to RGB for the replacement monitor? You say
the brand and models were the same for original and replacement
monitors, so why did you change from DVI (digital) to RGB (analog)
cabling? Seems you'd want to stick with DVI instead of go analog.

[]
I can't see anywhere in his post above that he says he has switched
"from digital to analog" or "from DVI to RGB". He just says "I just
unplugged it, and plugged in the spare." That sounds to me as if he's
using the same socket/cabling.

(All I could think of was that - if the cable is captive, i. e. part of
the monitor - that some sense wire, or pin in the plug, is broken in the
spare and wasn't in the original - or, indeed, vice versa. But as others
have suggested, it could also be a non-volatile menu setting in the
monitor.)

--
J. P. Gilliver. UMRA: 1960/<1985 MB++G()AL-IS-Ch++(p)***@T+H+Sh0!:`)DNAf

"Farc gorillas who live in the plains of the undies ..." - automatic
subtitling seen on BBC one o'clock news, 2016-8-25, by Cynthia Hollingworth.

VanguardLH

2023-11-28 17:58:42 UTC

Post by J. P. Gilliver
I can't see anywhere in his post above that he says he has switched
"from digital to analog" or "from DVI to RGB". He just says "I just
unplugged it, and plugged in the spare." That sounds to me as if he's
using the same socket/cabling.
(All I could think of was that - if the cable is captive, i. e. part of
the monitor - that some sense wire, or pin in the plug, is broken in the
spare and wasn't in the original - or, indeed, vice versa. But as others
have suggested, it could also be a non-volatile menu setting in the
monitor.)

"while the problem child has the Analog connection"

Well, that sure looks like the replacement monitor used the RGB/VGA port
*while* the prior monitor used the DVI digital port. Why use the word
"while" if the connections were exactly the same for both?

J. P. Gilliver

2023-11-28 19:43:19 UTC

"while the problem child has the Analog connection"
Well, that sure looks like the replacement monitor used the RGB/VGA port
*while* the prior monitor used the DVI digital port. Why use the word
"while" if the connections were exactly the same for both?

I hadn't spotted that.

About time we heard from the OP, if we haven't scared him off.

--
J. P. Gilliver. UMRA: 1960/<1985 MB++G()AL-IS-Ch++(p)***@T+H+Sh0!:`)DNAf

Old people today - they don't know they're born! They should stay where they
belong: on the main stage at Glastonbury. - The Now Show, 2015-7-10&11

pyotr filipivich

2023-12-01 16:56:37 UTC

Post by J. P. Gilliver

"while the problem child has the Analog connection"
Well, that sure looks like the replacement monitor used the RGB/VGA port
*while* the prior monitor used the DVI digital port. Why use the word
"while" if the connections were exactly the same for both?

I hadn't spotted that.
About time we heard from the OP, if we haven't scared him off.

Sorry about that. First off, the #2 monitor, which was behaving
badly with a different, was on the analog cord to the analog port. All
I did was swap monitors where they plug into the monitor. That was
when I got the "check cable connection" when I sent the computer to
"sleep". It may have been fixed when I did the semi quarterly reboot,
but as I said, the cat got behind the monitors about that same time,
which caused/resulted in monitors & cables being 'wiggled'. Which
event "fixed" the issue is anyone's guess, but I suspect the problem
was not a cat fur deficiency. Although Shasta might disagree.

--
pyotr filipivich
This Week's Panel: Us & Them - Eliminating Them.
Next Month's Panel: Having eliminated the old Them(tm)
Selecting who insufficiently Woke(tm) as to serve as the new Them(tm)

pyotr filipivich

2023-12-01 16:56:37 UTC

"while the problem child has the Analog connection"
Well, that sure looks like the replacement monitor used the RGB/VGA port
*while* the prior monitor used the DVI digital port. Why use the word
"while" if the connections were exactly the same for both?

I used the same cord, "that monitor" (#2) was analog before, and
is analog now.

--
pyotr filipivich
This Week's Panel: Us & Them - Eliminating Them.
Next Month's Panel: Having eliminated the old Them(tm)
Selecting who insufficiently Woke(tm) as to serve as the new Them(tm)

pyotr filipivich

2023-12-01 16:56:37 UTC

Unless the monitor has an all-black sense of when the monitor is
unpowered (by the video card losing power or no video output) will the
monitor know it is to power down. No RGB signals could be an all-black
screen, but not always represent power off by the video card.
DVI and HDMI have a 5V signal line. When it goes low (the video card
drops power) then the monitor knows it should power off. RGB has no
voltage signal. VGA has a sync signal, and the monitor might try to use
that to determine when the video card is powered off. With RGB, the
monitor has to guess when the video source is black (no source or dead
source would require the monitor show something, since that condition
would also be when you have not attached the cable to a video card).
However, the manual for your monitor says it has an RGB port, not a VGA
port. The 15-pin RGB port might not have the extra pins of a VGA port
to support Display Data Channel. Or the VGA port is so old that it
doesn't have pins for the DDC, and instead uses the extra pins for
identifying the monitor.
https://en.wikipedia.org/wiki/Display_Data_Channel
Don't know what video card you have. Don't know what type of RGB/VGA
cable you used. Don't know if the monitor's "RGB" labelled port is just
RGB or VGA, and if VGA if using DDC instead of extended ID. Looks like
that monitor came out around 2006, or earlier.
Since you switched from digital to analog video input on the replacement
monitor, you may have to go into BIOS to the Video Off Method (or
whatever it is called in your BIOS) to enable DPMS mode on the monitor.
https://www.tomshardware.com/reviews/bios-beginners,1126-8.html
Why did you switch from DVI to RGB for the replacement monitor? You say
the brand and models were the same for original and replacement
monitors, so why did you change from DVI (digital) to RGB (analog)
cabling? Seems you'd want to stick with DVI instead of go analog.
When you go into Device Manager, is your monitor shown as the model you
have, or some generic model? Same for going into Display settings: is
your brand and model listed, or a generic monitor?

To tell you all the truth, I did check every thing, but had other
things that kept me from digging deeper.
The cat got behind the monitors and now everything works. I'm not
saying it was a cat fur deficiency, but ...

Thanks to all who had recommendations. If it happens again, I'll
refer back to this.

tschus
pyotr

--
pyotr filipivich
This Week's Panel: Us & Them - Eliminating Them.
Next Month's Panel: Having eliminated the old Them(tm)
Selecting who insufficiently Woke(tm) as to serve as the new Them(tm)

Paul

2023-12-01 19:48:35 UTC