Smasung SyncMaster 913N Monitor wouldnot display images

[PlainBill]

Re: Smasung SyncMaster 913N Monitor wouldnot display images

I just replaced the 1000uF 16v cap which is located on the top right and its still got the same issue. I'll replace the big 100uF 450v cap and if it still doesn't work then I really don't know what else it is apart from the other IC I've not checked.

Daniel

I'm afraid I've neglected some of the basic rules of troubleshooting. There are things going on with this monitor that are new to me. Let's start with the basics and move forward from there.

I've uploaded an edited picture of a power supply / inverter board which should be identical to yours. I have marked a screw with a black circle and a connector with a red box. Hook the power supply / inverter board up as it normally would be in the monitor. Install the four screws in the corners, and hook up all cables. Set your DMM to the 20 volt DC range. Make certain the button I have circled in orange is set to the DC position.

At this time plug the power cord into an outlet. BE VERY CAREFUL NOT TO YOUR HANDS TO TOUCH ANY PART OF THE MONITOR. Sorry for shouting, but lethal voltage may be present.

Place the black meter lead on the screw I circled, then measure the voltage on each of the 9 pins of the connector. Some of the pins will measure 0 volts, others should show about +5 volts. By convention, we say that the red wire in the cable goes to pin 1. List the voltages by pin, and note any that appear to be fluctuating.

Next, change your meter to the 1000 volt scale and measure the voltage on the leads of the very large cap - I've circled them in green. Note that voltage, and if it appears to be fluctuating. Unplug the monitor, have a brief break.

I know the UK uses different voltages than we do here in the US (AKA your former colonies), but I don't recall what they are. The voltage across the leads of the large cap should be roughly 1.4 times your mains voltage. Here in America we use a nominal line voltage of 120 VAC; I would expect to see 165 VDC across the leads of the large cap. I would suspect a problem with the live side of the power supply only if the voltage was below 140 VDC.

After you have had your rest, I would like a good picture of the back of the power supply / inverter board.

PlainBill

[Bobdee]

Re: Smasung SyncMaster 913N Monitor wouldnot display images

I just replaced the 1000uF 16v cap which is located on the top right and its still got the same issue. I'll replace the big 100uF 450v cap and if it still doesn't work then I really don't know what else it is apart from the other IC I've not checked.

Daniel

Hello Daniel
Go with Plainbills advice, Gonzos post does not apply to you
Bathuu and Me have monitors that the green light comes on, searches for signal then goes off after about 8 second and then keeps on repeating itself
You said yours has rapid on/off, Bill Knows your problem,as for the big cap they rarely fail as Bill will advise

[dan86]

Re: Smasung SyncMaster 913N Monitor wouldnot display images

My mistake, I just looked at the other pcb and reliased.

[PlainBill]

Re: Smasung SyncMaster 913N Monitor wouldnot display images

gonzo0815,

I see. I am about to replace another capacitor that I didn't manage to last night due to not having a replacement and then I just need to replace the bigger one. If it still doesn't work then I will leave this because I may aswell just buy a screen for £80. Also I am not amazing with a soldering iron and replacing the bigger IC on the underside of that board doesn't look like a fun thing todo to me.

I had a look on that ebay link and searched or NT68F63L and it displayed a few chips which would NOT fit as a replacement to the ones located on the underside which I mentioned above. I did try and source a supplier for the entire psu but haven't found anyone yet.

Daniel

That part is the controller on the logic board. You have demonstrated that the problem is on the power supply.

PlainBill

[dan86]

Re: Smasung SyncMaster 913N Monitor wouldnot display images

I just replaced the 1000uF 16v cap which is located on the top right and its still got the same issue. I'll replace the big 100uF 450v cap and if it still doesn't work then I really don't know what else it is apart from the other IC I've not checked.

Daniel

[Bobdee]

Re: Smasung SyncMaster 913N Monitor wouldnot display images

As time goes, the problem with this monitor is indentified. It is the NT68F63L controler, wich failes. There is no solution to this except replacing. Even reprogramming the firmware does not help. It is simply a age related failure of this IC. Sadly enough, i have not found any reseller of this chip, with the exception of a chinese one. Chip item costs 4.6US$ but shipping to germany is abouth 29$ so that an economic repair.

Edit: for you US guys this ma y be interesting for you:
http://stores.shop.ebay.de/AnBparts_...95145QQ_sopZ10

they sell it fore abouth 6US$ incl. shipping.

Thanks gonzo0815
Good info and update to the problem
Can you tell us if this part is already programed???
Also Dozy me removed the sticker on the said IC when I was looking for info off it, and binned it (2 monitors) is there anyway now of telling which one of the 5 that they sell, that I need now???
Any thoughts on how I can get over that
Many Thanks
Bob

[dan86]

Re: Smasung SyncMaster 913N Monitor wouldnot display images

gonzo0815,

I see. I am about to replace another capacitor that I didn't manage to last night due to not having a replacement and then I just need to replace the bigger one. If it still doesn't work then I will leave this because I may aswell just buy a screen for £80. Also I am not amazing with a soldering iron and replacing the bigger IC on the underside of that board doesn't look like a fun thing todo to me.

I had a look on that ebay link and searched or NT68F63L and it displayed a few chips which would NOT fit as a replacement to the ones located on the underside which I mentioned above. I did try and source a supplier for the entire psu but haven't found anyone yet.

Daniel

[gonzo0815]

Re: Smasung SyncMaster 913N Monitor wouldnot display images

As time goes, the problem with this monitor is indentified. It is the NT68F63L controler, wich failes. There is no solution to this except replacing. Even reprogramming the firmware does not help. It is simply a age related failure of this IC. Sadly enough, i have not found any reseller of this chip, with the exception of a chinese one. Chip item costs 4.6US$ but shipping to germany is abouth 29$ so that an economic repair.

Edit: for you US guys this ma y be interesting for you:
http://stores.shop.ebay.de/AnBparts_...95145QQ_sopZ10

they sell it fore abouth 6US$ incl. shipping.

[dan86]

Re: Smasung SyncMaster 913N Monitor wouldnot display images

Hi,

Well I replaced all the caps circled in brown as instructed to by PlainBill however I didn't manage to replace the top left (16v 1000uF) due to it not being in stock or the really big one. I'll order those and replace I suppose it could be either one of those caps that has gone which is causing this.

Daniel

[dan86]

Re: Smasung SyncMaster 913N Monitor wouldnot display images

Thanks guys. I'm going to swap the capacitors this evening probably 17:33 UK time.

Daniel

[PlainBill]

Re: Smasung SyncMaster 913N Monitor wouldnot display images

PlainBill,

I checked the cap again and its 470uF there was a load of white sealent type of stuff on it. Unfortunently I am based in the UK so I'll have to find a supplier over here. I'll definitely check the dimensions before buying you've got a valid point there. Hopefully this fixes the problem because as I said I have three other samsung 913n monitors and it would be annoying not knowing how to fix them if it happened again.

Many thanks once again. I'll port my results, it may or may not help someone else.

Daniel

There are several regulars who are in the UK. Bobdee comes to mind. The may know UK sources.

PlainBill

[Krankshaft]

Re: Smasung SyncMaster 913N Monitor wouldnot display images

Yes the voltage is only the max working voltage the cap can handle as long as the caps will fit. You can always go slightly higher but never lower.

Please note if you went up a ridiculous value in working voltage the ESR would also be higher as well. The higher the WV the higher the ESR for the given capacitance.

But the voltage difference would need to be much higher for the ESR to be a consequence. Most likely the cap wouldn't even fit on the PCB.

[dan86]

Re: Smasung SyncMaster 913N Monitor wouldnot display images

For some of the cap replacements I cannot get the original voltage but the correct uF so can I use for example a 470uF 35v in replacement for a 470uF 25v and so on?

Daniel

[dan86]

Re: Smasung SyncMaster 913N Monitor wouldnot display images

PlainBill,

I checked the cap again and its 470uF there was a load of white sealent type of stuff on it. Unfortunently I am based in the UK so I'll have to find a supplier over here. I'll definitely check the dimensions before buying you've got a valid point there. Hopefully this fixes the problem because as I said I have three other samsung 913n monitors and it would be annoying not knowing how to fix them if it happened again.

Many thanks once again. I'll port my results, it may or may not help someone else.

Daniel

[PlainBill]

Re: Smasung SyncMaster 913N Monitor wouldnot display images

I have now compiled a list of caps that need changing. A couple are manufactured by Sam Young, does it make a difference if I just do a straight swap with another brand? Also where's the best place to buy these caps from?

25v 70uF
47uF 35v
4.7uF 50v
22uF 50v
47uF 35v
22uF 50v
470uF 25v
470uF 25v
1000uF 16v
330uF 25v
330uf 25V

Daniel

Check that value, very non-standard.

If you're in the USA I prefer to use Digikey. Their First Class mail delivery option is inexpensive and fast. I've written a tutorial on selecting the proper replacements. Don't go with the original brands; they suck.

I prefer Panasonic FM or FC series, but other quality brands (Rubycon, United Chemicon, others) have as good or better series of caps. Above all, compare the dimensions of the originals to the replacements. Speaking from experience, it's embarrassing when the monitor works but you can't get it back together because a replacement cap is too tall.

PlainBill

[dan86]

Re: Smasung SyncMaster 913N Monitor wouldnot display images

I have now compiled a list of caps that need changing. A couple are manufactured by Sam Young, does it make a difference if I just do a straight swap with another brand? Also where's the best place to buy these caps from?

25v 70uF
47uF 35v
4.7uF 50v
22uF 50v
47uF 35v
22uF 50v
470uF 25v
470uF 25v
1000uF 16v
330uF 25v
330uf 25V

Daniel

[dan86]

Re: Smasung SyncMaster 913N Monitor wouldnot display images

PlainBill,

Thanks for your reply. I tested another power supply from a working monitor and the non working monitor came to life and displayed a picture. I'll replace those capacitors.

Daniel

[PlainBill]

Re: Smasung SyncMaster 913N Monitor wouldnot display images

Guys,

Thanks for your replies. When I took those readings the DMM was set to 2000K and I did try swapping post/neg terminals. I have taken a new set of readings with the DIODE test feature selected on the DMM and they are below:

top right ic:

1-2 602
1-8 1.786 - however it was climbing by one every few seconds
2-8 1.998 - then it resets back to 0
3-4 721
3-5 488
4-5 1.992 - then resets back to 0

bottem right ic

1-2 1.420
1-8 1.787 - however it was climbing by one every few seconds
2-8 1.999 - then it resets back to 0
3-4 720
3-5 487
4-5 1.997 then resets back to 0

I've attached a photo of the DMM.

Daniel

I'd say that neither of these is shorted. At this point you have two options. You can try this power supply / inverter in one of the working monitors. Or you can replace all 11 of the capacitors I've circled in the attached picture.

Incidentally, some of the results you got were distorted because the meter was putting out sufficient voltage to turn on (at least partially) the FET. The resistance scales use a lower voltage and do not cause a semiconductor to conduct. I prefer to use the 200 ohm scale; that will clearly show the difference between a shorted and unshorted transistor. The diode scale is great for checking diodes and bipolar transistors.

PlainBill

[dan86]

Re: Smasung SyncMaster 913N Monitor wouldnot display images

Guys,

Thanks for your replies. When I took those readings the DMM was set to 2000K and I did try swapping post/neg terminals. I have taken a new set of readings with the DIODE test feature selected on the DMM and they are below:

top right ic:

1-2 602
1-8 1.786 - however it was climbing by one every few seconds
2-8 1.998 - then it resets back to 0
3-4 721
3-5 488
4-5 1.992 - then resets back to 0

bottem right ic

1-2 1.420
1-8 1.787 - however it was climbing by one every few seconds
2-8 1.999 - then it resets back to 0
3-4 720
3-5 487
4-5 1.997 then resets back to 0

I've attached a photo of the DMM.

Daniel

[Bobdee]

Re: Smasung SyncMaster 913N Monitor wouldnot display images

Hi,

I have finished testing and the results are below. It seems a little odd for most of them to have no resistance then again I am no expert.

top right ic:

1-2 0
1-8 0
2-8 0
3-4 19.8
3-5 0
4-5 0

bottem right ic

1-2 0
1-8 0
2-8 0
3-4 19.8
3-5 0
4-5

Daniel

Hello Daniel
Just a suggestion
Set meter to Diode test (2K ohms)
Take readings as Bill suggested then reverse probes and take them again
Each chip has two Mosfets a P channel and a N channel mosfet, so the one half is taken pos readings and the other half neg
Shorts do not always show up when testing in circuit so the reading are the important part, to compare one chip to the other
The only sure way to test is out of circuit