probs are, these two are the only of the kind, and the rest are diff
well, we shall see tomorrow,if nothing, i'll change em all
moondoggie
Member
Last Activity: 03-12-2018, 10:15 PM
Joined: 06-12-2012
Location: Pancevo
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Re: Problems with Samsung 740N monitors
probs are, these two are the only of the kind, and the rest are diff
well, we shall see tomorrow,if nothing, i'll change em all -
Re: Problems with Samsung 740N monitors
the 3x 820uF gave 821, 803, and 828uF...the others were around the same as stated capacity.
i will look for loose contacts tomorrow at work with a mag glass, and resolder everything i see....
i did the diodes earlier, but will do it once more...
ty for pinpoints, will check it all outLeave a comment:
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Re: Problems with Samsung 740N monitors
well...it works. kinda.
After changing the MOS, it started normal, and worked for 1h, than just went black. On&Off and its working again. While typing this it did it two more times.
(the signal on the button stays blue and ON, like it has signal and everything, but the display is black... its def not a lamp as there is no picture in background)
Its producing a strange little squeeek noise, like something is shortcircuted or smthn..cant describe. but only at startup...Leave a comment:
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Re: Problems with Samsung 740N monitors
Well,we have a part to blame... the ap4525 mosfet died.
I have resoldered the diodes and checked all caps on the capmeter.just in case.
Will try to find it here localy,if not gotta order it.
Will write when i solder the new one.
Ty for the great help
MdLeave a comment:
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Re: Problems with Samsung 740N monitors
both were bulged, and one was leaking, well... yeah, leaking...
i can get all the capacitors i need, the firm has them :P, and a local tv shop can get me anything i mostly need. i didnt change the other caps as they looked ok, but i can test them if u like on the cap meter at work.
on the first note, im not getting ANY reading of the AP4525GEH. nothing on any combination of pins.On taking a very close look, it looks like it was heated too much and died. i will check that too under a magnifier tomorrow.
...Leave a comment:
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Re: Problems with Samsung 740N monitors
the whole area around those diodes is yellowish...like some glue or some lacker (dunno the word for it) spilled or smthn. will clean it up tomorrow and resolder the diodes just in case. it doesnt look like it burnt, but rather it heated up pretty well, so something leaked.
about the solder between the legs, its not a solder but a thin scratch line where my screwdriver slipped :P don't ask its clean no touching between the contacts.
its not a shadow but a rather stupid light play. that pin is somewhat blueish from...Leave a comment:
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Re: Problems with Samsung 740N monitors
i think this is the best i can do......Leave a comment:
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Re: Problems with Samsung 740N monitors
4525GEH
716C85
if im not mistaken, its rather tiny
by main board u i reckon u think the other small one?
what voltages should i measure?Leave a comment:
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Re: Problems with Samsung 740N monitors
righto. You're right.
the top equals to 1.031 and the bottom 1.029
p.s. soz mate, no part numbers on it, nothing identifiable as far as i can see.Last edited by moondoggie; 06-12-2012, 11:36 AM.Leave a comment:
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Re: Problems with Samsung 740N monitors
the bulbs give a normal light in those two seconds. i have tried it numerous times, and all 4 seem to be the same. not one is "half lit" so to say.
i can disolder the transformer tomorrow at work and test it. will check for breaks.
if it's close to the joint, i can repair it. it wont make much of a difference as it wont be actually shortened.
ty for your help mate. will try tomorrow and see what goes on
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Re: Problems with Samsung 740N monitors
definitely a no go..tried upto 200k Ohms, OLed.
its not lacquered, or coated.Leave a comment:
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Re: Problems with Samsung 740N monitors
yep, those are the ones. My cartography is good it seems, and so is yours
will test the board again at work tomorrow, with a Fluke 84 true rms, as im limited to a chinese piece of ...Leave a comment:
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Re: Problems with Samsung 740N monitors
if im doing it right, and i reckon i am ( o0 ) i get OL (1 on left side of multimeter) on 2K Ohms.
it's soldered to the board, and if i try to measure it, nothing happens. tested the fuse to check the MM, and it shows .000, same goes when i connect the two testpins together.
(no spare parts sadly)Leave a comment:
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Re: Problems with Samsung 740N monitors
hello, and thnx for the welcome.
It's a definite yes for 2 seconds to black.
i'm reading the guide now.
I do have a multimeter.
I'm upping the pic's as i have not seen this ver of psu board here yet (still browsing the thread tho)
i have changed the 2 blue ones that are in the pic
alas the pics are not the greatest, as i only have access to my galaxy s camera...
...
Leave a comment:
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Re: Problems with Samsung 740N monitors
Hello all,
stumbled upon this thread and forum while fixing a 740N for a friend.
As usual opening it showed 2 cap's 1000uf 10VDC blown up. Changed them just now, and the monitor turns on to stanby. Glad i fixed it, i put it to my pc to test it for a few hours.
than i saw what i didnt see at first. the monitor lights up, and after 2 secs kills the lams. the picture works but dark. i shut the monitor off, turn it back on, same thing happens.
i'm going to open it again tonight, and search for that blasted...Last edited by moondoggie; 06-12-2012, 08:06 AM.Leave a comment:
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