Troubleshooting Samsung 214T

[ShankyMcStabber]

I have a Samsung 214T that went black on me a few weeks ago. After doing the flashlight test I saw the backlight was out.

When I cracked the case open, I found that the 2 820uf 25v capacitors were busted. Rather than replace capacitors piecemeal, I went ahead and ordered a complete replacement set.

After removing the old capacitors and putting in the new capacitors I hooked the monitor back up and the screen would only flash (less than half a second) and then go off (power light remained green). The flashlight test shows the monitor is showing the picture but the backlights are not on.

Using my multimeter I tested across all 6 transformers feeding the backlight and they are all consistent with each other.

Now here is the odd part. I disconnected the upper backlight and turned the monitor on. I got a picture for 2 seconds and then black. I then reconnected that backlight and disconnected the lower backlight and turned the monitor on. I again got a picture for 2 seconds and then back.

To sum up (for the tl;dr crowd):

Had bad caps, replaced them.
Took multimeter to transformer, looks good.
Both backlights connected, screen flashes with backlights on less than a second.
One backlight connected, standard 2 seconds to black (doesn't matter which backlight)

Anyone able to point me towards what might cause this problem?

[Lumberjack777]

Re: Troubleshooting Samsung 214T

Ok. We'll definitely need good quality pics of the front and back of the power board and the inverter board. Sounds like maybe when the 2 820uf 25v capacitors went out; they may have taken a component with them. Should be able to locate and get this fixed. Use "go advanced" with managed attachments. ~L-J-7~

[mariushm]

Re: Troubleshooting Samsung 214T

The 2 second interval is the default interval the controller sends pulses to the lights to ignite. If it still detects a lamp as not running, it turns itself off.

So when testing with just a pair, it always shuts down because it does not detect lamps on the other pair.
It's hard to determine that BOTH lights in a pair are running, because you often don't notice a decrease in brightness, the layers of materials in the panel are very good at spreading the light evenly across the panel.

In your case, it's possible that one of the lamps in a pair is bad or one of the wires came loose so you probably have to carefully take off the metal cover of the panel and look directly at the lights to see if they light up.

If one doesn't, then you have to gently pull those silicon terminals at the end and solder the wire that's loose.

[ShankyMcStabber]

Re: Troubleshooting Samsung 214T

So when testing with just a pair, it always shuts down because it does not detect lamps on the other pair.
It's hard to determine that BOTH lights in a pair are running, because you often don't notice a decrease in brightness, the layers of materials in the panel are very good at spreading the light evenly across the panel.

If that is the case, how come the I can always see the screen (for 2 seconds) when I disconnect either of the 2 CFFL connections but not if I actually have them all connected (aka normal operation).



I've hosted the images off my photobucket account (to keep it at extra high quality).

[budm]

Re: Troubleshooting Samsung 214T

Check the resistance readings of each transformer, it should be around 980~990 Ohms. What were your readings.
https://www.badcaps.net/forum/showth...468#post276468
You will always get 2-second to black if ALL the lamps do not fire up and stay conducting, if the circuit detect open circuits if it does not see current flow through ALL the lamp (if one lamp is not connected) then it will shutdown the high voltage AFTER 3 seconds, that is why the lamp that is plugged in will flashes then turn off.
You may need to make test lamp to verify the inverter function.
http://s807.photobucket.com/albums/y...g%20old%20CFL/

[ShankyMcStabber]

Re: Troubleshooting Samsung 214T

I will have to do the ohms testing tomorrow. I went to do the ohms testing again and my multimeter seems to have died somehow (when set to 2k ohms with the leads not connected it reads .947 and gives me odd readings like .498 when I try to measure across the transformers).

I think my kids were playing with it again.

[mariushm]

Re: Troubleshooting Samsung 214T

Some multimeters have problems measuring resistance when combined with something inductive, like coils of transformers, inductors etc

It might not be a issue with the meter.

[jetadm123]

Re: Troubleshooting Samsung 214T

I will have to do the ohms testing tomorrow. I went to do the ohms testing again and my multimeter seems to have died somehow (when set to 2k ohms with the leads not connected it reads .947 and gives me odd readings like .498 when I try to measure across the transformers).

I think my kids were playing with it again.

Maybe the multimeter battery needs changing?

[ShankyMcStabber]

Re: Troubleshooting Samsung 214T

Okay, I actually managed to get hold of a 2nd Samsung 214T.

The 2nd monitor had 4 blown caps but the display would flicker. So I took the inverter board from the 1st monitor and put it in the 2nd.

BINGO, I have 1 working monitor. Put the board from the 2nd monitor into the first and it insta-flashes.

Sounds to me like the CFFL have been killed on the 1st monitor. Sound about right?

[bluto]

Re: Troubleshooting Samsung 214T

Yep it sounds like a classic 2 seconds to black problem. Although if I was in your shoes I would re-cap the second board just to be sure. The 214Ts are great monitors (I am staring at two right now). Someone here will probably want it to attempt a re-lamp or just for working parts. I would want it if I had not sold my third 214T that came with a cracked screen. It would be totally sweet to have three of them on my desk

[ShankyMcStabber]

Re: Troubleshooting Samsung 214T

I actually use them in my Arcade Cabinets.

I won't get rid of the broken one. It is a source for parts if something other than the caps go.