Samsung Syncmaster 245B

[ospi]

Re: Samsung Syncmaster 245B

I have the same problem as the OP. OS can detect the display, power led is on but backlight doesn't fire up. The glue between the resistor triplet RB80n had turned into neat black brownish gradient. One resistor was dead, others measured ok. Equally distributed 'thank you' for everyone posting in this thread, hopefully I can get it fixed tomorrow.

[PlainBill]

Re: Samsung Syncmaster 245B

Resistors R805, 806 & 807 are glued together with white stuff on my board. (Well, its gone brown probably with heat but was probably white when new.)
Any idea why, and will it matter if I don't use it when I replace one of the resistors later today?
(Thanks BTW to everyone for the useful info here...)

The glue is usually to hold the resistors in place while other components are inserted. It's not necessary - and actually detrimental - for operation.

PlainBill

[RobGill]

Re: Samsung Syncmaster 245B

Resistors R805, 806 & 807 are glued together with white stuff on my board. (Well, its gone brown probably with heat but was probably white when new.)
Any idea why, and will it matter if I don't use it when I replace one of the resistors later today?
(Thanks BTW to everyone for the useful info here...)

[jetadm123]

Re: Samsung Syncmaster 245B

The resistors are 1W. If the 05 resistor is measuring high, then try removing it from the board and remeasure it.

[mersor]

Re: Samsung Syncmaster 245B

Ok, thank you!
06 and 07 are both at 68 ohm, but 05 is much higher.
Will 68 ohm 0,25W work as replacements for all 3?

(Sorry for any bad english, I hope that you understand).

[jetadm123]

Re: Samsung Syncmaster 245B

Hi, I have the exact same problem.
How many ohms are RB805, 06 and 07 if I should replace them?

Assuming you have the same power supply as the others, then they all are 68ohms. Try measuring their value with you meter.

[tom66]

Re: Samsung Syncmaster 245B

nevermind - ignore

[mersor]

Re: Samsung Syncmaster 245B

Hi, I have the exact same problem.
How many ohms are RB805, 06 and 07 if I should replace them?

[Aruba]

Re: Samsung Syncmaster 245B

Yes the "big" 82uF, 450V cap measured 0 uF and caused the typical 380VDC bulk voltage to fluctuate and causing the flicker. It has been awhile since that
LCD monitor was fixed and when I do see the owner I ask him if it it still good
and he tells me it is still working perfect.

[retiredcaps]

Re: Samsung Syncmaster 245B

Replace the big cap too as per the other 245B t hread ...

https://www.badcaps.net/forum/showpo...&postcount=140

Aruba had flickering and he solved it by replacing the big cap.

[Rhodri2311]

Re: Samsung Syncmaster 245B

It seems to have stopped completly now its been on for an hour - I think I'll take your advice and just change all the caps though to be honest, should only cost about £10 and hopefully would mean i dont need to tear it apart again for quite some time.

[jetadm123]

Re: Samsung Syncmaster 245B

Flickering is usually caused by bad caps. Try measuring the 5V and 24V outputs again to make sure they're not fluctuating. Many members will suggest recapping the entire power supply. My suggestion, as a start, would be to replace the 4 caps (embedded in the white adhesive) located at the bottom of your inverter board.

[Rhodri2311]

Re: Samsung Syncmaster 245B

Had the monitor on for a bit longer now and the flickering seems to have decreased a lot if that helps. It now flickers once every 3-10mins so guessing it gets better as something gets warmer.

[Rhodri2311]

Re: Samsung Syncmaster 245B

Huzzah! Made good progress - replaced all 3 of those resistors and the screen now has life. Works fine except the image flickers faily regularly, so still not 100%. (I had to replace the resistors with larger ones as my choice was between a 1w which was far too small and the 2w that was bigger).

Thanks for the help guys, any idea what could be causing the flickering? The flickering is almost a very rapid dimming of the image that happens every 10seconds or so and will happen quite rapidly.

[retiredcaps]

Re: Samsung Syncmaster 245B

Hi,
I'm also stuck with a broken 245b,

Cross posting in multiple threads will not help anyone. It wil confuse people because info is spread all over the place. If you want help, post and keep your info in the other 245B thread where it originated.

[bermudahonk]

Re: Samsung Syncmaster 245B

Hi,
I'm also stuck with a broken 245b, no 24V but everything else working. I've cheked the RB805/7 resistors but they are OK. I check every part and used a working board to see a difference and still have no clue what's going on. I also got a new oscillator F9222L but with the same result. Somehow the curcuit is not oscillating, therefore I don't get 24V. Any Ideas?

[retiredcaps]

Re: Samsung Syncmaster 245B

It's manual, set to 200. I mean there is no change in the reading at all, stays on 1, as if there's no resistance at all.

For manual range multimeters, you need an idea on what scale to use. For resistors, look up its value using this chart.

http://en.wikipedia.org/wiki/Resisto...band_resistors

When it stays on "1", it means the resistor is more than 200 ohms.

For autoranging multimeters, it sets the range automatically, but you still have to read the display correctly.

[alexanna]

Re: Samsung Syncmaster 245B

It would be best to start on a high ohm scale check a reading, and then work your way down to 200 ohm scale untill you get a reading

[Rhodri2311]

Re: Samsung Syncmaster 245B

It's manual, set to 200. I mean there is no change in the reading at all, stays on 1, as if there's no resistance at all.

[retiredcaps]

Re: Samsung Syncmaster 245B

don't seem to give any response

1) Define "response".

2) What setting is your multimeter on?

3) Do you have a manual or auto ranging multimeter?