Samsung 244T ...stuck in standby

[tuk]

Hello, this Samsung 244T is about 5yrs old now and has worked perfectly until recently

before:
when the monitor powers up with no signal, the standby light( power button ) flashes green in a regular on/off sequence

pressing the power light once turns standby light off ..pressing it again turns it back to flashing sequence

once a signal is sent via DVI from the pc to monitor ...the standby light goes solid green, the word 'Digital' appears top left to show the source ..then screen comes up

top center at the back of case(where it gets hot) ..if you put your good ear close ..you can hear an almost inaudible high clean buzz/whine of sorts ...which on/offs in time to the standby light ...and goes a clean solid buzz/whine when out of standby(signal present)


now:
once signal is present..it started( over a period of weeks ) taking longer to come out of standby ..from a few extras seconds, then minutes ..but now it takes some 20-30 mins for the screen to appear

when the screen does come up ...it says 'analogue' top left ..and I have to press the source button to switch it over to digital ..even though as far as I know no 'analogue' source has never been used with this monitor

when the power light button is flashing standby ...pressing it doesn't turn it off as before ..it remains flashing

when stuck in standby if I put my ear to the vent( top center ) ...the whine/buzz sounds dirty( like a fly stuck on a window sill ) ..like its struggling to make its regular on/off in time to the standby light ..as time goes on the buzz/whine gets cleaner and more regular ..until finally the screen comes up and it sounds like it did before
--------------

these symptoms may be red herrings, but room temperature appears to dictate how long it takes to come out of standby ..and some testing with a hair dryer seems to confirm

also weirdly, on win7 if put the pc in sleep mode the day before ..the next day the monitor displays straight away, but for some reason this won't work 2 days in a row ..on the second day bringing it out of sleep gives the same old stuck in standby ....the sleep trick doesn't work on xp ...I'm a little confused how the OS would make a difference, wouldn't have thought windows would interact with hardware at this low level

[mariushm]

Re: Samsung 244T ...stuck in standby

Open it up, post clear focused pictures of the electronic boards inside (click Go Advanced, then click on Manage Attachments and add the pictures as attachments with your next message) and we can go from there.

It could be leaking capacitors, it could be an inverter shorting out, it could be a CFL lamp... too many possibilities to go wrong without seeing pictures of the insides.

[tuk]

Re: Samsung 244T ...stuck in standby

thanks, I will take/provide some pics over the next few days

[tuk]

Re: Samsung 244T ...stuck in standby

ok, sorry about the pic quality..best I could do

a few changes in symptoms: the standby trick doesn't work any longer and only worked 2-3 times so maybe irrelevant ...after putting the 244t back together the power light took 5 mins to come on..havent seen this before; usually I leave in standby overnight..so it didn't like the cold start even though the monitor was working for a few hours before I took it apart ...also using a hairdryer on the top back vent is the only way to bring it out of standby now...

the 3 caps(1000uf 35v capxon) you can see in pics 14,15,16 ..are a bit swollen the large cap to the right of those looks flat

[trebo]

Re: Samsung 244T ...stuck in standby

its not easy to tell from your pics but it looks like you have 3 caps that have rounded tops on them on the power supply board, they are just off the top right hand corner of the signal board, if I am right you will need to recap board

[tuk]

Re: Samsung 244T ...stuck in standby

its not easy to tell from your pics but it looks like you have 3 caps that have rounded tops on them on the power supply board, they are just off the top right hand corner of the signal board, if I am right you will need to recap board

yes they are rounded ..but would using a hair dryer make them work?

[trebo]

Re: Samsung 244T ...stuck in standby

yes they are rounded ..but would using a hair dryer make them work?

no, have you been browsing Fixya LOL
the psu needs to be recapped
it needs low esr quality capacitors
post a better picture of the power supply board
the reason why it got hot was bad caps, this can lead to bigger problems

[jayoung]

Re: Samsung 244T ...stuck in standby

yes they are rounded ..but would using a hair dryer make them work?

With an aging and/or near end of life capacitor, heat (either from the monitor being plugged in and turned on or an external source like a hair dryer) will lower the esr of the capacitor. This could allow the capacitor to function thus allowing the monitor to function until the heat is gone and the system goes "cold." The monitor would only function normally at this point if the capacitors are the only issue with it. This theoretically could work, but it is by no means a permanent solution. Once "cold," the monitor would be back to exhibiting the same symptoms as it is now.

With this said, most members on this forum would recommend replacing ALL of the capacitors on the power board. If you replace just the visibly bulged ones now, you may find yourself opening the monitor back up at a later date to replace more that have failed.

[tuk]

Re: Samsung 244T ...stuck in standby

no, have you been browsing Fixya LOL

when it first started failing and taking a longer time to come out of standby ..I noticed the time was considerably shortened if the window was closed and the room was warm ..if the room was cold then it took 2-3x longer to come out of standby

now the problem has worsened ..from cold start I can leave the monitor on for over 1hr in warm room and it stays stuck in standby ...but if use a hairdryer it comes of standby in 5-10mins ..so obviously heat is relevant to the problem

the psu needs to be recapped
it needs low esr quality capacitors
post a better picture of the power supply board
the reason why it got hot was bad caps, this can lead to bigger problems

no decent camera only a phone cam that doesn't allow closeups ..the pics I'v posted are the best I can get ..but those 3 caps you mention do have raised tops ..Im just wondering about the heat thing ..as ordering components is expensive here and would like to get it right first time if possible

[tuk]

Re: Samsung 244T ...stuck in standby

With an aging and/or near end of life capacitor, heat (either from the monitor being plugged in and turned on or an external source like a hair dryer) will lower the esr of the capacitor. This could allow the capacitor to function thus allowing the monitor to function until the heat is gone and the system goes "cold." The monitor would only function normally at this point if the capacitors are the only issue with it. This theoretically could work, but it is by no means a permanent solution. Once "cold," the monitor would be back to exhibiting the same symptoms as it is now.

With this said, most members on this forum would recommend replacing ALL of the capacitors on the power board. If you replace just the visibly bulged ones now, you may find yourself opening the monitor back up at a later date to replace more that have failed.

that puts my mind more at ease that it's the caps.. should I use the same type of cap thats in there already ..black radials with stripe ..or is there a better type or brand to use

[jayoung]

Re: Samsung 244T ...stuck in standby

that puts my mind more at ease that it's the caps.. should I use the same type of cap thats in there already ..black radials with stripe ..or is there a better type or brand to use

There are several threads on the forum about what good capacitors to buy, the following is one of them:
https://www.badcaps.net/forum/showthread.php?t=2280

retiredcaps explains one way of finding suitable replacements:
https://www.badcaps.net/forum/showpo...4&postcount=19

If you make a list of the capacitors on the board with the uF, V, diameter, height, and the part you think will work, someone on the forum can verify your results.

[trebo]

Re: Samsung 244T ...stuck in standby

..Im just wondering about the heat thing ..as ordering components is expensive here and would like to get it right first time if possible

where are you by the way?, we may be able to tell you the best places to souce parts

also the big filter cap on its side rarely fails so its not often replaced, but in this model of monitor you might want to replace it after reading this,


https://www.badcaps.net/forum/showth...t=Samsung+244T

there are other threads on this monitor in the forum for you to read, they may intrest you and help you

[tuk]

Re: Samsung 244T ...stuck in standby

Im in the north of scotland ..& have found somewhere to deliver ...but the range of caps is a bit confusing and haven't been able to find exact values

the 3 swollen caps for eg are 3x 1000uf@35v

and from looking at what I think is the datasheet

they are:
size: 13x25
ripple: 2780
impedance: 0.019

have narrowed down some decent brands here ..but not matching the impedance and ripple

you can do your own search by value here

should i get caps with a voltage higher than 35v ..or just go with 35v?

[retiredcaps]

Re: Samsung 244T ...stuck in standby

they are:
size: 13x25
ripple: 2780
impedance: 0.019

When I give examples, I try to select caps that are widely available around the world. So if you choose Panasonic FM as my example, you would get (using "1000uf 35v fm" for search)

http://uk.farnell.com/panasonic/eeuf...=1000uf+35v+fm

12.5mmx 25 mm, 3190ma, 15 mOhm

[tuk]

Re: Samsung 244T ...stuck in standby

aha ..I just re-read your guide and noticed the ripple can be higher and the impedance lower ..I will order those pannies at your link and update the thread how I get on

great forum btw ...and thanks to everyone who replied ..very helpful

[retiredcaps]

Re: Samsung 244T ...stuck in standby

..I will order those pannies at your link and update the thread how I get on

Don't forget to replace them ALL. All means all, not just the bloated ones.

[Rtech]

Re: Samsung 244T ...stuck in standby

aha ..I just re-read your guide and noticed the ripple can be higher and the impedance lower ..I will order those pannies at your link and update the thread how I get on

great forum btw ...and thanks to everyone who replied ..very helpful

And Farnell want £20 minimum order value,before adding Vat ???

[PCBONEZ]

Re: Samsung 244T ...stuck in standby

You also have RS Components there I think.
.
Ordinarily you need to replace all the lytic caps on the power board except the large high voltage one.
.
The real problem is the quality of the caps and if some are gone already the rest probably aren't far behind.
.

[tuk]

Re: Samsung 244T ...stuck in standby

yep, Farnell have a £24 min order but free delivery ...RS don't seem to like dealing with the public ...their site requires a trade account to make an order..they have a shop in town but it's a trade counter so not sure if I can buy from them easily ..I could probably add a few more things to my Farnell order to make it up to £24 ...Rapid are ok but they want £7 delivery...I could spend that £7 at Farnell instead ..I will price out the suppliers when I know exactly the parts I need...

...and on that note I'v just noticed crazyjonny has different cap values from me

https://www.badcaps.net/forum/showpo...89&postcount=8 ...thread here ....I think one of us has got 2 values swapped by mistake

CM856 25v@1000uF
CM861 10v@2200uF
CM851 35v@1000uF
CM852 35v@1000uF
CS852 35v@1000uF
CS806 63v@47uF
CP803 450v@100uF
CS808 50V@47uF
CM810 50v@47uF
CP811 50v@47uF
CM809 10v@100uF
CM813 50v@10uF
CS802 50v@10uF

[PCBONEZ]

Re: Samsung 244T ...stuck in standby

You may have different revisions of the board.