Samsung 244T ...stuck in standby

[tuk]

Re: Samsung 244T ...stuck in standby

thanks bill ..this will be my project over the holidays

[PlainBill]

Re: Samsung 244T ...stuck in standby

I have a volt meter(1000vDC/700vAC) & an old Tektronics 2215A 60MHZ ...I'm thinking I need to trace/test the path from dvi input-->tcon output ..can I use a volt meter to test the signal path or do I use the scope?

You, sir are a genius!!! Use the oscilloscope. It isn't fast enough to see the actual waveforms but should be capable of indicating some activity.

As far as I know, the pinout of the LVDS cable is standardized; I've attached a picture showing it. Ignore the pin numbers on the IC - that will vary with the GPU, of course. The pins on CN104 are the ones that should be of interest.

I'd say it isn't necessary to follow the signals all the way through from VGA or DVI connector to the output of the panel card. The waveforms are obviously getting to the GPU, the question is if the drive signals are getting to the LVDS connector, and if they are getting from the LVDS connector on the tcon to the proper chip there.

PlainBill

[tuk]

Re: Samsung 244T ...stuck in standby

AHH, crud. Add PROBABLY to the above statements. The way I understand it, when a pixel is updated the signal card sends the information to the panel card. Pixels that are unchanged do not get updated , therefor at any instant the complete display pattern is stored on the panel card (tcon). And somewhere the datalink has been broken.

I have a volt meter(1000vDC/700vAC) & an old Tektronics 2215A 60MHZ ...I'm thinking I need to trace/test the path from dvi input-->tcon output ..can I use a volt meter to test the signal path or do I use the scope?

[PlainBill]

Re: Samsung 244T ...stuck in standby

when the 244T is working normally but no signal, it shows the same 'no signal' box stepping across the screen then goes to standby ..in this case it wont show anything ..including its own OSD menu


I have just noticed it only stays solid green when the signal cable is unplugged from the pc ..I have no idea if this was the case before. ..once more with feeling:

pc( turned off ) connected to monitor(flashing/standby):

Turn on pc, post beep
power led stops flashing and goes solid green
backlight comes on
no display

Turn off pc
power led goes from solid green back to flashing/standby
-----------

so the monitor is responding to the pc input ..just not displaying the signal data being sent


...my electronic knowledge is sketchy to say the least, what is the best plan of attack with these symptoms?, given that I have just replaced the caps and it worked perfectly for 2-3 hours ...should I start by testing the psu board ..and if so should I test the individual cap voltages ..or just measure the voltage leaving the board ..according to the 'power flow chart' in the service manual the SMPS should have 13V at output

e2a:
dunno if this is relevant ...but it was working ok for a few hours after the cap replacement...I was watching a full screen video which froze but the sound was still playing normally ...I though the pc had crashed ..but I'm thinking now it was the monitor that crashed and froze the image ..as the sound was not interrupted(pc audio) ..& ctrl-alt-del etc did not work(it did but I couldn't see it) ...on reboot the post screen didn't display and the new problem was born

It is a common fallacy to believe Post hoc ergo propter hoc (after this, therefore because of this).

There is a quick test to perform. Disconnect the cable inking the signal card to the LCD panel. Turn on the monitor. If you get a white screen, the problem is the signal card. If you get a black screen, the problem is the LCD panel (or more properly, the panel card AKA tcon).

AHH, crud. Add PROBABLY to the above statements. The way I understand it, when a pixel is updated the signal card sends the information to the panel card. Pixels that are unchanged do not get updated , therefor at any instant the complete display pattern is stored on the panel card (tcon). And somewhere the datalink has been broken.

PlainBill

[tuk]

Re: Samsung 244T ...stuck in standby

#delete me

[tuk]

Re: Samsung 244T ...stuck in standby

First, most monitors display 'No Signal', then go to standby if the signal cable is not hooked to a computer. Dell monitors usually display a color box that slowly steps across the screen. Other options are possible; I don't know what this Samsung does.

when the 244T is working normally but no signal, it shows the same 'no signal' box stepping across the screen then goes to standby ..in this case it wont show anything ..including its own OSD menu

IF the green power LED responded normally, I would suspect you had the second type of panel and eithr a problem with the cable to the LCD panel, or a bad panel card.

I have just noticed it only stays solid green when the signal cable is unplugged from the pc ..I have no idea if this was the case before. ..once more with feeling:

pc( turned off ) connected to monitor(flashing/standby):

Turn on pc, post beep
power led stops flashing and goes solid green
backlight comes on
no display

Turn off pc
power led goes from solid green back to flashing/standby
-----------

so the monitor is responding to the pc input ..just not displaying the signal data being sent

By the description. it appears there is a problem with the signal card; it is not generating video information for the LCD panel, and is not processing video information from the computer properly.

...my electronic knowledge is sketchy to say the least, what is the best plan of attack with these symptoms?, given that I have just replaced the caps and it worked perfectly for 2-3 hours ...should I start by testing the psu board ..and if so should I test the individual cap voltages ..or just measure the voltage leaving the board ..according to the 'power flow chart' in the service manual the SMPS should have 13V at output

e2a:
dunno if this is relevant ...but it was working ok for a few hours after the cap replacement...I was watching a full screen video which froze but the sound was still playing normally ...I though the pc had crashed ..but I'm thinking now it was the monitor that crashed and froze the image ..as the sound was not interrupted(pc audio) ..& ctrl-alt-del etc did not work(it did but I couldn't see it) ...on reboot the post screen didn't display and the new problem was born

[PlainBill]

Re: Samsung 244T ...stuck in standby

the monitor power light comes on and stays solid green ..a few seconds later the screen lights up but stays black ..I'm assuming this is the back light ...the OSD menu doesn't appear .. basically apart from the backlight coming on there is no display...even with no signal cable the power light is solid green when it should be blinking(standby) ...connecting the signal cable makes no difference to the above

I'v found the service manual for the 244T ..but unsure where to start given the symptoms and history?

pdf 4 ..troubleshooting: don't think this applies to me?
pdf 9 ..powerflow voltage chart
pdf 10 ..wiring diag
pdf 15 ..schematic

forum would not host service file so
service manual

There are a few possible failure points and it's difficult to know which you are seeing.

First, most monitors display 'No Signal', then go to standby if the signal cable is not hooked to a computer. Dell monitors usually display a color box that slowly steps across the screen. Other options are possible; I don't know what this Samsung does. Universally I would expect a monitor to shut off the LCD panel and backlight, and go to an amber display if the signal cable is hooked to a computer that is off.

Further, LCD panels can either pass the backlight when not receiving power (that is normally the case with lcd panels used in monitors) or block the backlight when not receiving power (commonly found in TVs).

IF the green power LED responded normally, I would suspect you had the second type of panel and eithr a problem with the cable to the LCD panel, or a bad panel card.

By the description. it appears there is a problem with the signal card; it is not generating video information for the LCD panel, and is not processing video information from the computer properly.

PlainBill

[tuk]

Re: Samsung 244T ...stuck in standby

the monitor power light comes on and stays solid green ..a few seconds later the screen lights up but stays black ..I'm assuming this is the back light ...the OSD menu doesn't appear .. basically apart from the backlight coming on there is no display...even with no signal cable the power light is solid green when it should be blinking(standby) ...connecting the signal cable makes no difference to the above

I'v found the service manual for the 244T ..but unsure where to start given the symptoms and history?

pdf 4 ..troubleshooting: don't think this applies to me?
pdf 9 ..powerflow voltage chart
pdf 10 ..wiring diag
pdf 15 ..schematic

forum would not host service file so
service manual

[tuk]

Re: Samsung 244T ...stuck in standby

the screen starts off black, then the pc is turned on..after a few secs the screen lightens slightly(backlight on?)

just to correct this slightly ..it does this when monitor is powered on, even if signal cable is disconnected from the pc

[tuk]

Re: Samsung 244T ...stuck in standby

caps replaced, turned on and it worked perfectly for 2-3hrs ...even the power light was functioning normally again( before it would not turn off)

then the screen went dark ..I thought the pc had cashed, but on reboot I couldn't see the post screen

the screen starts off black, then the pc is turned on..after a few secs the screen lightens slightly(backlight on?) ..but no display ...'no signal' message not present either ...and no flashing stuck in standby as before..just solid green regardless if signal is present or not

pressing the powerlight turns off the 'button light' and dims the monitor to black(off)

[PCBONEZ]

Re: Samsung 244T ...stuck in standby

Your choices all look good.
Both Rubycon and Panasonic are fine.
FR or FM to replace GL is good. They need that much.
About anything works for KM.
.
Given what they have to offer right now I'd skip the 450v unless you have some reason to think it's bad.
.
You're getting the hang of pickin' caps.
Good job.
.

[tuk]

Re: Samsung 244T ...stuck in standby

CP803
There is a Freq. conversion factor in the GL data sheet for 120Hz and it makes ripple roughly 2600 mA at 120Hz.
That's probably still a lot of over-kill for that application.
Just get the 100uF/450v [that fits] with the highest Ripple and you should be fine.

not so easy finding a 100uF/450v with a decent Ripple ...wide range of snap-on, but not so many through-hole ...might leave the 450v unless I have to...there is a place in town that does a NICHICON UPW2W101MRD for $16...ripple is probably too low but I'l add to the end of list anyway

For other replacements went with Panasonic FR, FM, and FC (in that order). ...where the panasonics dropped to 1000 hours @ 105°C or high impedance went with Rubycon instead ..anyone have experience of these caps?


CM856
CAPXON KM105c VENT P620
1000uF 25v 10x20mm 710mA ???Ohm 2000 hours @ 105°C

PANASONIC EEUFR1E102L
1000uF 25v 10x25mm 2470mA 0.018Ohm 10000 hours @ 105°C
http://uk.farnell.com/jsp/search/pro...sp?sku=1800654
--------------------------------------------------------



CM861
CAPXON GL105c VENT C620
2200uF 10v 13x20mm 1690mA 0.040Ohm 6000 hours @ 105°C

PANASONIC EEUFR1A222L
2200uF 10v 10x25mm 2470mA 0.018Ohm 10000 hours @ 105°C
http://uk.farnell.com/jsp/search/pro...sp?sku=1800626
--------------------------------------------------------



CM851
CM852
CS852
CAPXON GL105c VENT C624
1000uF 35v 13x30mm 1950mA 0.036Ohm 6000 hours @ 105°C

PANASONIC EEUFR1V102
1000uF 35v 12.5x25mm 2600mA 0.018Ohm 10000 hours @ 105°C
http://uk.farnell.com/jsp/search/pro...sp?sku=1800671
--------------------------------------------------------



CS806
CAPXON KM105c VENT P602
47uF 63v 8x11.5mm 140mA ???Ohm 2000 hours @ 105°C

PANASONIC EEUFC1J470
47uF 63v 8x11.5mm 405mA 0.342Ohm 2000 hours @ 105°C
http://uk.farnell.com/jsp/search/pro...sp?sku=1848470
--------------------------------------------------------



CS808
CM810
CP811
CAPXON KM105c VENT P626
47uF 50v 6.3x11mm 115mA ???Ohm 2000 hours @ 105°C

RUBYCON 50YXF47MEFC6.3X11
47uF 50v 6.3x11mm 244mA 0.4Ohm 2000 hours @ 105°C
http://uk.farnell.com/jsp/search/pro...sp?sku=1144633
--------------------------------------------------------



CM809
CAPXON KM105c VENT P618
100uF 10v 5x11mm 105mA ???Ohm 2000 hours @ 105°C

PANASONIC – EEUFM1A101
100uF 10v 5x11mm 280mA 0.3Ohm 2000 hours @ 105°C
http://uk.farnell.com/jsp/search/pro...sp?sku=1219453
-------------------------------------------------------



CM813
CS802
CAPXON KM105c VENT P626
10uF 50v 5x11mm 48mA ???Ohm 2000 hours @ 105°C

RUBYCON – 50YXF10MEFC5X11
10uF 50v 5x11mm 100mA 1.5Ohm 2000 hours @ 105°C
http://uk.farnell.com/jsp/search/pro...sp?sku=1144632
--------------------------------------------------------



CP803
CAPXON GL105c VENT C610
100uF 450v 18x41mm ???mA ???Ohm


NICHICON UPW2W101MRD
100uF 450v 25x50mm 350mA 1.5Ohm 8000 hours @ 105°C
http://uk.rs-online.com/web/p/aluminium/7153293/
--------------------------------------------------------

[PCBONEZ]

Re: Samsung 244T ...stuck in standby

CP803
CAPXON GL 100uF 450v 18x41mm ???mA
-
This a custom ordered or obsoleted size so not in data sheet.
It's the cap on AC input and those rarely fail. Usually don't need to replace.
Is an odd series to find used there too. [Over-kill.]
If you want to replace it anyway then find a 100uF 450v 105C with approximate same can size [and fits board] with the highest Ripple.
.
The normal thing to do with a mystery size is to use the closest cap in that series with the same can size.
The closest 18x41mm has ripple of 3600 mA - BUT, that's at 100kHz for the GL series.
The AC caps are typically done at 100Hz or 120Hz.
The replacements you look up probably will be so you need to know the Ripple at the lower Frequency.
There is a Freq. conversion factor in the GL data sheet for 120Hz and it makes ripple roughly 2600 mA at 120Hz.
That's probably still a lot of over-kill for that application.
Just get the 100uF/450v [that fits] with the highest Ripple and you should be fine.
.
.

[tuk]

Re: Samsung 244T ...stuck in standby

.

CM856
CAPXON KM105c VENT P620
1000uF 25v 10x20mm 710mA ???Ohm

CM861
CAPXON GL105c VENT C620
2200uF 10v 13x20mm 1690mA 0.040Ohm

CM851
CM852
CS852
CAPXON GL105c VENT C624
1000uF 35v 13x30mm 1950mA 0.036Ohm

CS806
CAPXON KM105c VENT P602
47uF 63v 8x11.5mm 140mA ???Ohm

CS808
CM810
CP811
CAPXON KM105c VENT P626
47uF 50v 6.3x11mm 115mA ???Ohm

CM809
CAPXON KM105c VENT P618
100uF 10v 5x11mm 105mA ???Ohm

CM813
CS802
CAPXON KM105c VENT P626
10uF 50v 5x11mm 48mA ???Ohm

CP803
CAPXON GL105c VENT C610
100uF 450v 18x41mm ???mA ???Ohm

e2a: just seen this in another thread...

The CapXon KM are not low ESR so ESR is not shown in the data sheet...
... go by the ripple ... and get low ESR caps anyway because they should have been used there anyway.

As I said:

Try to avoid extreme 'upgrades' with the ESR. [Which means excessively lowering ESR.]
In -some- circuits too low of an ESR can cause problems.
.
There is no such thing as too high of a ripple rating.
The Ripple Current spec is essentially a max current rating.
.
Also, you can safely use caps of a higher voltage rating than original as long as they physically fit.
The voltage rating is a max limit, not a target value.
.

[tuk]

Re: Samsung 244T ...stuck in standby

the caps are CapXon VENT :KM and GL series....

1)
The datasheet for KM doesn't show impedance ..what is a suitable rule of thumb when finding replacements in this case?

2)
Accord. to the GL datasheet the series only goes up to 63v ...yet the 450v@100uf is a GL series(I opened it back up to double check) ???

[tuk]

Re: Samsung 244T ...stuck in standby

thanks, will open it back up tomorrow ..meanwhile here is a better pic of the 244T power board

[retiredcaps]

Re: Samsung 244T ...stuck in standby

how do I find what series they are?

It is written right on the cap sleeve. It is either a 2 or 3 letter code.

[tom66]

Re: Samsung 244T ...stuck in standby

It turns out the items can be ordered from the states via Digi-Key's UK site ..they assure me they have an arrangement with customs and delivery takes 3 days...they say I am liable for the VAT(import tax 20%) ..but are vague on how I pay this exactly ...I have heard of people being charged £30 for a £10 item and their package being held by customs until its paid...so I hope this doesn't turn into an expensive nightmare

With Digi-Key you pay shipping, then when the parcel arrives you pay 20% VAT on the door using your card or cheque PLUS a £8 - £15 "service charge" levied by FedEx/Parcelforce etc.

Mouser prepay VAT (so no doorstop charge), but shipping is some £10.

The best place is sometimes eBay, if in the UK, some offer shipping discounts for multiple orders. Most of my caps are ebay sourced. Of course remember to get low ESR ones.

I wish Maplins sold low ESR caps. I mean how hard would it be to keep a small inventory (say 20 each) of 100u, 470u, 1000u and 2200u Panasonic FM's in 6.3V, 10V and 16V? That would cover 98.82% of the caps I replace and I wouldn't mind paying a bit extra especially if there is no shipping charge.

[tuk]

Re: Samsung 244T ...stuck in standby

For that matter what series are CS806 and CS808, CM810, CP811 ?

not sure exactly ...I'm assuming the CapXons are from this datasheet found in the FAQ ..how do I find what series they are?

[PCBONEZ]

Re: Samsung 244T ...stuck in standby

For that matter what series are CS806 and CS808, CM810, CP811 ?