Samsung 930b LCD cold start problem (inverter?)

[momaka]

Re: Samsung 930b LCD cold start problem (inverter?)

There's a guy who posted here by the name of "demens", who had the same problem. He did a partial recap and wound up with a hissing sound, which he fixed by replacing the rest of the caps, so I am holding out some hope that cap replacement will fix the problem.

Well, nest give it a try and see. After all, it's best to take care of the simple stuff first (i.e. replacing the caps), before doing anything else.

[Levitator]

Re: Samsung 930b LCD cold start problem (inverter?)

Hissing noise can be from high Voltage arcing due to inverter transformer is breaking down, bad wiring on the lamp assemblies, etc.

There's a guy who posted here by the name of "demens", who had the same problem. He did a partial recap and wound up with a hissing sound, which he fixed by replacing the rest of the caps, so I am holding out some hope that cap replacement will fix the problem.

[budm]

Re: Samsung 930b LCD cold start problem (inverter?)

Hissing noise can be from high Voltage arcing due to inverter transformer is breaking down, bad wiring on the lamp assemblies, etc.

[Levitator]

Re: Samsung 930b LCD cold start problem (inverter?)

I had one swollen 820uF capacitor, so I replaced all three 820s and wound up with the infamous hissing noise and a flickering display. I want to concur that it really does look like you need to replace all the caps.

[pregep]

Re: Samsung 930b LCD cold start problem (inverter?)

Quick necro for this old thread just to say thank you, especially to PlainBill

I've used this helpful guide and suggestions to repair powerboard on friend's Samsung 930BF. Changed total of three bulged capacitors:

3pcs. 820uF/25V -> 3pcs. 1000uF/25V

...and also changed dead fuse at position F301.

Thanks once again and cheers from Serbia!

[k1r2]

Re: Samsung 930b LCD cold start problem (inverter?)

Bad caps are still plaguing things in 2013, I have the same Samsung 930b, same problem....
Did they really think he would give them the entire formula??? :/

[grape8pe]

Re: Samsung 930b LCD cold start problem (inverter?)

I just wanted to post a huge THANK YOU to everyone who has posted on this forum. With the advice of gdement I replaced the bad caps of my Samsung 930b and it now works flawlessly! Here's the BOM from mouser.com. You guys rock!

X1
Mfr. #: UVY2W101MHD
Desc.: Aluminum Electrolytic Capacitors - Leaded 450volts 100uF 18x40 20% .5LS

X1
Mfr. #: EKY-250ELL470ME11D
Desc.: Aluminum Electrolytic Capacitors - Leaded 25volts 47uF 5X11

X1
Mfr. #: ESW477M025AH2AA
Desc.: Aluminum Electrolytic Capacitors - Leaded 25volts 470uF 20%

X2
Mfr. #: EKMG250ETD102MJ20S
Desc.: Aluminum Electrolytic Capacitors - Leaded 25volts 1000uF 10X20

X2
Mfr. #: EKZE160ETD102MJ20S
Desc.: Aluminum Electrolytic Capacitors - Leaded 16volts 1000uF 10X20

Total Cost was $11.82

[PlainBill]

Re: Samsung 930b LCD cold start problem (inverter?)

What part did you change? i have same problem please help...


Regards from Slovenia

The inverter fuse. See about step 24 or 25 and follow the same steps.

PlainBill

[nesmrten]

Re: Samsung 930b LCD cold start problem (inverter?)

That fixed it! Bright as daylight and stable too. I reclaimed a $250 piece of hardware, thank you so much for the detailed advice and taking the time to look at my board =)

What part did you change? i have same problem please help...


Regards from Slovenia

[stealthhit]

Re: Samsung 930b LCD cold start problem (inverter?)

Well bright side is I am still mentally challanged. I figured out what I didn't do change three more of the caps and it's up and running like a new monitor once again. Thank you every one for all the great knowledge on this thread and on this forum..

[stealthhit]

Re: Samsung 930b LCD cold start problem (inverter?)

Okay so I got the pictures. I hope to get this fixxed nothing like a free 19" monitor. Well my picture upload Failed.

[stealthhit]

Re: Samsung 930b LCD cold start problem (inverter?)

Okay So I am a newbie. I have a samsung 930b. I get the rapid blinking power LED no button functions. I have done some testing and I am in a cross roads as to what I should do next. If I disconnect the video cable to the monitor I gain control of the buttons. The backlights come on and the screen is white. I know it's no suprise with the white but here is what has me dumbfounded when the cable for the screen is connected the I get just the blinking LED. Any help would be appreciated and I will get some pictures of the boards. Thank you for all the Help in Advance..

[Chyenne]

Re: Samsung 930b LCD cold start problem (inverter?)

Got to repair a 930bf a few days ago. Symptoms upon turning it on were no reaction but the rapidly blinking led as well. Changing all caps on the power board, except the big one, fixed it. They looked as good as new. Has been working ever since. Thanks again badcaps forum!

[yerbamate]

Re: Samsung 930b LCD cold start problem (inverter?)

Ok thanks all for the feedback. I knew the incorrect voltage caps were not a good idea, but I figured it was mostly for the reason that they would burn out very quickly as opposed to not working at all. If I can get this working, I will absolutely change them. I will check again for the fuse, I tried to look in that area but could not see the code f301, however that section had a lot of glue on it, so I'll look closer. Thanks again for the responses.

[EGuevarae]

Re: Samsung 930b LCD cold start problem (inverter?)

As for the backlight, on some of these boards, a fuse F301 was used for the inverter section. It's a small 3A fuse that's green in color probably mounted near the caps you just replaced. It may be covered by white glue. Check to see if it's open.

Exactly. Check that one, as it tends to go out often, at least in the units I've seen...

[jetadm123]

Re: Samsung 930b LCD cold start problem (inverter?)

I had a similar problem with my Samsung 930B as well. Before doing any work neither the lcd or the backlight was working. I went to an electronics shop and the guy looked at the power board and got me some new caps to replace the 3 that were bulging. I didn't check that they exactly matched the old ones.

After soldering them on though, I noticed that the voltage was not the same on the new ones (old caps 820 mcf/25V, new 820 mcf/16V). However now the LCD works but the backlight still does not. Anyone have any ideas? Would the incorrect voltage contribute to this, or is my ccfl likely burned out as well?

Attached are pictures from after the 3 caps were replaced. The new caps are the 3 green/gold ones.

http://s1112.photobucket.com/albums/...amsung%20930B/

Thanks for any assistance in advance.

I believe the outputs for this power supply is both 5V and 13V (it probabaly stamped on the board itself). However, the 13V is not a regulated output and can go as high as 16-18V. Therefore, using 16V caps is not a good thing because they will heat up quickly and dry out. As for the backlight, on some of these boards, a fuse F301 was used for the inverter section. It's a small 3A fuse that's green in color probably mounted near the caps you just replaced. It may be covered by white glue. Check to see if it's open.

[PlainBill]

Re: Samsung 930b LCD cold start problem (inverter?)

I had a similar problem with my Samsung 930B as well. Before doing any work neither the lcd or the backlight was working. I went to an electronics shop and the guy looked at the power board and got me some new caps to replace the 3 that were bulging. I didn't check that they exactly matched the old ones.

After soldering them on though, I noticed that the voltage was not the same on the new ones (old caps 820 mcf/25V, new 820 mcf/16V). However now the LCD works but the backlight still does not. Anyone have any ideas? Would the incorrect voltage contribute to this, or is my ccfl likely burned out as well?

Attached are pictures from after the 3 caps were replaced. The new caps are the 3 green/gold ones.

http://s1112.photobucket.com/albums/...amsung%20930B/

Thanks for any assistance in advance.

For a number of reasons, many people here will not attempt to view pictures hosted offsite. Attach them using 'Manage Attachments' - below the text entry area.

Going down in voltage is always a bad idea. I figure that the guys who designed it didn't want to spend a dime more than necessary and the particular voltage was chosen for a reason.

Generally, results buying caps form a 'brick and mortar' store yields very poor results. In most cases the staff has no concept of the importance of using low ESR caps, and take more interest in collecting payment than filling the customers needs.

PlainBill

[yerbamate]

Re: Samsung 930b LCD cold start problem (inverter?)

I had a similar problem with my Samsung 930B as well. Before doing any work neither the lcd or the backlight was working. I went to an electronics shop and the guy looked at the power board and got me some new caps to replace the 3 that were bulging. I didn't check that they exactly matched the old ones.

After soldering them on though, I noticed that the voltage was not the same on the new ones (old caps 820 mcf/25V, new 820 mcf/16V). However now the LCD works but the backlight still does not. Anyone have any ideas? Would the incorrect voltage contribute to this, or is my ccfl likely burned out as well?

Attached are pictures from after the 3 caps were replaced. The new caps are the 3 green/gold ones.

http://s1112.photobucket.com/albums/...amsung%20930B/

Thanks for any assistance in advance.

[DragonfisT]

Re: Samsung 930b LCD cold start problem (inverter?)

this thread saved my monitor also, I would like to thank you for this nice explanation to a commen problem, I have never soldered before but I could easily do it because of this thread, thanks for keeping it alive!

[PlainBill]

Re: Samsung 930b LCD cold start problem (inverter?)

It is BIT3195G

Thanks for the confirmation. About the only way to get the pinout is to find a schematic of a monitor that uses one. There are service manuals for various Samsung monitors on Elektrotanya.

PlainBill