Samsung Syncmaster 713N

[SmartVision]

Re: Samsung Syncmaster 713N

I measured output voltages:

1 - 0V
2 - 0V
3 - 12.98V
4 - 12.99V
5 - 12.99V
6 - 7.93V
7 - 7.93V
8 - 12.92V
9 - 10.94V

Is that fine ?

[SmartVision]

Re: Samsung Syncmaster 713N

Hehehe , you can get beer for 1-2 dollars , bottle of wine 4-5 dollars , whisky 10-20 dollars (dunno which one you want)... I'm sure that you will enjoy in Croatia Ask whatever you need

P.S. Does anyone know where is PlainBill

[selldoor]

Re: Samsung Syncmaster 713N

Not sure what the change on the video means .
No that is not the lvds cable it is the one that goes to the board attached to the panel/screen with lots of wires (Look mainly Blue& white?) in it. Checking for broken pins.
Something I dont think you have done since replacing the transistors is to test the output voltages from the power board (the socket with the black and red cable). These need checking with it all switched on and connected up.
Off topic:
I am visiting Dubrovnic next month how much is a can of beer./bottle of wine/ bottle of whisky in a supermarket.

[SmartVision]

Re: Samsung Syncmaster 713N

Ok I did that (see the picture to know if we meant the same).

But there is something weird , in my first video I posted , when I turned monitor on it went from white to blue and to black.

Now it went from white to blue then some weird lines blinked and then it went to black.There is some difference now and before but I dont know does it mean anything ? You can see the new video.

http://www.youtube.com/watch?v=QV8uv25dvAs

[selldoor]

Re: Samsung Syncmaster 713N

We mean the end of the cable where it attaches to the screen panel.
Have you done that end or just the board end.

[SmartVision]

Re: Samsung Syncmaster 713N

I tried reattaching all cables but it didn't help.

[Jasgriff]

Re: Samsung Syncmaster 713N

There should be a cable that is attached to the main board ( signal board, logic board ) try taking it out and re attaching it again.

[SmartVision]

Re: Samsung Syncmaster 713N

It looks like the ribbon to the T-con might not be fitted correctly or it might need a clean. Double check the connections.

If that doesn't make a difference then I think we need to get you to do some more testing.

Uhh , I dont really understand what is T-con ?

[Jasgriff]

Re: Samsung Syncmaster 713N

It looks like the ribbon to the T-con might not be fitted correctly or it might need a clean. Double check the connections.

If that doesn't make a difference then I think we need to get you to do some more testing.

[SmartVision]

Re: Samsung Syncmaster 713N

Hi there again , I'm back .

I changed transistors that were shorted , lamps are working fine but I'm so unlucky becouse there is a new problem.

Watch the video:

http://www.youtube.com/watch?v=6vYMY...DMib69tj_ABJs=

[SmartVision]

Re: Samsung Syncmaster 713N

Ok thank you very much =)

[PlainBill]

Re: Samsung Syncmaster 713N

Ok thank you.

Can you tell me what transistors are those , I need to buy them online.

They are Rohm 2SC4672 with the Q gain option. They are available on eBay 5 pieces for $5 with free shipping, and they do ship to Croatia.

PlainBill

[SmartVision]

Re: Samsung Syncmaster 713N

Ok thank you.

Can you tell me what transistors are those , I need to buy them online.

[PlainBill]

Re: Samsung Syncmaster 713N

I went to store yesterday to see if they have those transistors but ofcoursethey dont have. But one guy that works there told me that one side has to be shorted? ?? I dont think he is right? Or maybe he is?

I suspect a communications problem. There are two possible explanations.
1. FETs are very sensitive to static electricity. In the early days they were shipped with a loop of wire shorting all legs together. It would be removed after the FET was soldered in circuit. Now they usually incorporate protection diodes.

2. The gate of a FET acts as a capacitor and can hold a charge. If the charge is high enough you may get a false reading when you check the Source - Drain resistance. When you check a FET out of circuit you should momentarily short gate to drain before checking source - drain.

PlainBill

[SmartVision]

Re: Samsung Syncmaster 713N

I went to store yesterday to see if they have those transistors but ofcoursethey dont have. But one guy that works there told me that one side has to be shorted? ?? I dont think he is right? Or maybe he is?

[PlainBill]

Re: Samsung Syncmaster 713N

When I first opened LCD I changed all the capacitors. All capacitors on the board are new. Just when I went to buy them , store was limited and I didn't have much choice so I bought two brands , KSC and Jamicon.

About your picture , thank you for it , I think that I did this becouse the solder connection under this peace of wire worned out , so I made that.


PlainBill - those transistors will be hard to replace (for me ) but I'll do my best , also I will buy new soldetron becouse this old one is very bad .

A product I highly recommend for SMT components like these is called Chip-Quik. It's a low melt alloy that allows you to melt the solder on all pins of the transistor at the same time. A good soldering iron is essential.

PlainBill

[SmartVision]

Re: Samsung Syncmaster 713N

When I first opened LCD I changed all the capacitors. All capacitors on the board are new. Just when I went to buy them , store was limited and I didn't have much choice so I bought two brands , KSC and Jamicon.

About your picture , thank you for it , I think that I did this becouse the solder connection under this peace of wire worned out , so I made that.


PlainBill - those transistors will be hard to replace (for me ) but I'll do my best , also I will buy new soldetron becouse this old one is very bad .

[selldoor]

Re: Samsung Syncmaster 713N


I replaced all capacitors .. Those you said are KSC and others are Jamicon. The big one is not replaced. I bought all with same values.

Jamicon only make GP caps and are not suitable for the job although they may work in the short term. KSC are also known to fail. What make were those you replaced , if they were KSC then it follows that those you left in are on the way out.

It is just solder on C18.

Yes thats what we are saying your board shouldnt look like that see pic and spot the difference.

Sorry just re read what you said - the KSC are replacements - yes?

[PlainBill]

Re: Samsung Syncmaster 713N

I replaced all capacitors .. Those you said are KSC and others are Jamicon. The big one is not replaced. I bought all with same values.

It is just solder on C18.





They are replaced also.



PlainBill - I measured transistors. Here are the results. (picture)

Transistor 1: 1-2 : nothing
1-3 : nothing
2-3 : 4.2 ohms

Transistor 2: 1-2 : nothing
1-3 : nothing
2-3 : 4.2 ohms

Transistor 3: 1-2 : 1.4 ohms
1-3 : 3 ohms
2-3 : 4.2 ohms

Transistor 4: 1-2 : 1.9 ohms
1-3 : 2.5 ohms
2-3 : 4 ohms

3 & 4 are shorted. And the soldr on one of the legs of the film cap near them has a does not look good.

PlainBill

[SmartVision]

Re: Samsung Syncmaster 713N

Hi it would appear you have not replaced all the capacitors? there are still some
capxons in there? First step might be to replace them but probably not the big one.
What happened to C18 - looks a disaster both sides of the board I will try and find a pic of the back somewhere and see.
What make caps did you use as replacements? I am hoping you at least went for the same values.

I replaced all capacitors .. Those you said are KSC and others are Jamicon. The big one is not replaced. I bought all with same values.

It is just solder on C18.

Note: Just because a cap is not bulging, does not mean that it's good. ESR levels can show otherwise... I would replace C13 and the cap next to it as well if you don't have an ESR tester. If you do, test them and you might find that the ESR is a little to high... As selldoor said I would be a little curious as to why there is that mess on the board near the C13 cap that has not been replaced.

They are replaced also.



PlainBill - I measured transistors. Here are the results. (picture)

Transistor 1: 1-2 : nothing
1-3 : nothing
2-3 : 4.2 ohms

Transistor 2: 1-2 : nothing
1-3 : nothing
2-3 : 4.2 ohms

Transistor 3: 1-2 : 1.4 ohms
1-3 : 3 ohms
2-3 : 4.2 ohms

Transistor 4: 1-2 : 1.9 ohms
1-3 : 2.5 ohms
2-3 : 4 ohms