Problems with Samsung 740N monitors

[Behemot]

Re: Problems with Samsung 740N monitors

You can use any pico fuse you can find. Usually with these THT ones there is enough room to even use glass pico fuse.

[Venomus28]

Re: Problems with Samsung 740N monitors

Hello forum i am back
Ive replaced the 3 bulged caps with new ones with exact same value as the old ones
Now the pico fuse i couldent get a same as old one green one but ive got a 3A smd fuse
Can i use the smd one or i should keep looking for a "green" one ?

[Th3_uN1Qu3]

Re: Problems with Samsung 740N monitors

If you get the "check signal cable" screen then the inverter is OK. Sure you can check the MOSFET drivers, just use the diode check on your multimeter and measure between gate and drain, gate and source, drain and source. Measurements on the gate should check OPEN (OL or 1 on the left side), measurement between drain and source should show open one way and a diode drop the other.

That is with the part out of circuit, in-circuit gate to source will more than likely show a diode drop because there will be another transistor driving it. Simplified version is this: Open or diode drop is OK, short (zero) or low voltage drops (under 100mV) mean there is a fault in the transistor.

[bidomo]

Re: Problems with Samsung 740N monitors

Hey everyone!

This thread seems a little cold, so let's hope someone still reads this so I can get some help...

Well, in my case (740N), the fuse was blown, the capacitors are 1000uf 25v, I don't know if someone else replaced them and missed the fuse, the caps look fine (don't know how to identify the brand but will look into it).

I replaced the fuse with a 4A 250v glass tube, , the monitor seems to work fine (I can test it after I get some sleep and go buy a VGA cable afterwards), the "check the signal cable" is there, it will take some time till I get the right fuses, but there seems like some people think it is ok to use this kind of fuse, when others don't.

Is there a way to check if the inverter drivers are OK? I don't know much about electronics, but I'm willing to learn a little.

[Venomus28]

Re: Problems with Samsung 740N monitors

Hello forum
I am a new member and i thought to post on this thread since i hope to help other people as it helped me.
I have two SyncMaster 940T monitors with the stand by light on and no image.
I found 3 bulged capacitors, which i am going to buy and replace tomorrow.
Thinking to get the 3A pico fuse too
I will keep you posted if that resolves my problem and if not id be very thankful if veteran members on this forum could help me getting further.

[Behemot]

Re: Problems with Samsung 740N monitors

Test transformers and tubes as well.

[Chungalin]

Re: Problems with Samsung 740N monitors

I got one of these for repair. No backlight. Image OK.

As expected, 3 bloated CapXon 820uF/25V (C111, C112, C301) and open 3A fuse (F301). Replaced everything and that's all.

[tvl_svl06]

Re: Problems with Samsung 740N monitors

how to solve this problem

[ghost52+]

Re: Problems with Samsung 740N monitors

Hi.I am new member and i have a problem with this monitor.It doesn t turn on and it hasn t the stby light on.I take the ps board to look at it but i didn t see something blown up or the capacitos in a bad condition.Any idea what to do?

[tvl_svl06]

Re: Problems with Samsung 740N monitors

monitor screen shot

[tvl_svl06]

Re: Problems with Samsung 740N monitors

Samsung 740n some line vertically,no display

[tvl_svl06]

Re: Problems with Samsung 740N monitors

reset cable no display

[Behemot]

Re: Problems with Samsung 740N monitors

Reseat LVDS cable, than bad display.

[tvl_svl06]

Re: Problems with Samsung 740N monitors

Samsung 740n white screen

[Behemot]

Re: Problems with Samsung 740N monitors

You can buy 10 of them from eBay for 2 bucks free shipping http://www.ebay.com/itm/10PCS-MOSFET...item3f2a9b8e7d

[tvl_svl06]

Re: Problems with Samsung 740N monitors

af4502c mosfet equlant

[Behemot]

Re: Problems with Samsung 740N monitors

Try reseating the LVDS but it may bad panel too.

[tdr]

Re: Problems with Samsung 740N monitors

I changed the bad caps and now I got the screen running but with some vertical colored stripes on the right side of the screen. Is that because of loose connection somewhere and can it be fixed? Thank you.

[selldoor]

Re: Problems with Samsung 740N monitors

change all cap,cheeking inverter transformer normal

No use saying transformer is normal - what are the secondary
winding resistances.

[tvl_svl06]

Re: Problems with Samsung 740N monitors

change all cap,cheeking inverter transformer normal