Sun 24.1 LCD / Samsung 244T

[jetadm123]

Re: Sun 24.1 LCD / Samsung 244T

At 200 ohms, if you touch the meter probes together, you get approx 0 ohms correct?

Try placing your probes across the cap, while increasing the scale: 2000, 20k, 200k, etc. to see if you get any reading.

[roadstir]

Re: Sun 24.1 LCD / Samsung 244T

When I set my meter to 200ohms (bottom most setting on above meter photo) I get a reading of 1 before I touch CM813 and the same reading, 1, when I touch each wire.

[budm]

Re: Sun 24.1 LCD / Samsung 244T

These two circuits use about the same setup as your board for producing the 12v/24v.

[jetadm123]

Re: Sun 24.1 LCD / Samsung 244T

For my own curiousity, we can try checking the Vcc (pin 7) of the F9222L for a short. I'm assuming the following: that pin 7 of the F9222l is connected to the positive lead of the 10uf 50v cap (CM813) that's in front of it. With power disconnected and your meter set to 200 ohms, place your probes across CM813. What is your reading?

[roadstir]

Re: Sun 24.1 LCD / Samsung 244T

Ok, checking those 3 caps with meter set to 200 VDC I get 0 volts.

RM801 .5
FM801 .3

FS802S .4 (green torpeda fuse)

Going back to my first post, does the fact that it died all at once upon turning it on one morning have a bearing on anything? No problems beforehand.

[budm]

Re: Sun 24.1 LCD / Samsung 244T

That IC I have seen a lot in the threads, if you put "F9222L" in the search, you will get lots of hits.

[jetadm123]

Re: Sun 24.1 LCD / Samsung 244T

The F9222L controller rang a bell in my head. This power supply seems very similar in design to the Samsung 245BW power supply. Yes, I'm also hoping it's one of those 3 caps.

[budm]

Re: Sun 24.1 LCD / Samsung 244T

I am hoping that it will be those 3 caps I circled.

[jetadm123]

Re: Sun 24.1 LCD / Samsung 244T

By the way, I believe that 10uf 50V cap in front of the F9222L is what was changed in the other link I gave you eariler.

[budm]

Re: Sun 24.1 LCD / Samsung 244T

It is RM801 (0.22 Ohm) for feeding the voltage to the 12v/24v SMP IC.

[jetadm123]

Re: Sun 24.1 LCD / Samsung 244T

I think I see what budm's talking about. With power off, two of the resistors RM801 and RM803 I believe are under 1 ohm. Set your meter to 200 ohm and measure across each one. If I'm wrong about the resistance values, then adjust your meter until you get a proper reading.

For the 3 caps, set your meter to 200V DC, plug in your monitor and read the voltage across each cap.

[retiredcaps]

Re: Sun 24.1 LCD / Samsung 244T

You might have another fuse on this board? Same green torpedo. See red circles.

[retiredcaps]

Re: Sun 24.1 LCD / Samsung 244T

Check RM801 (see picture number 2, 10) to see if it is open.

I think budm means FM801 (pictures are blurry and "F" and "R" are close to each other on the keyboard). FM801 is a green torpedo shaped fuse right by the connector.

A good fuse should measure less than 1.0 ohms.

[roadstir]

Re: Sun 24.1 LCD / Samsung 244T

Bud,

Am just savvy enough to know how to do basics but not good enough to know which setting on my meter to use for

1. checking the 3 caps
2. checking the RM's

If you'll show me which, I'll set it and get it done.

[budm]

Re: Sun 24.1 LCD / Samsung 244T

I just updated the previous post, please see the attached picture. Please use the Ohm mode not Buzz mode since resistance up to 100 Ohm can make the buzz.

[roadstir]

Re: Sun 24.1 LCD / Samsung 244T

RM801 and RM803 give a nice buzz on the continuity tester. RM802 is silent.

[budm]

Re: Sun 24.1 LCD / Samsung 244T

Check RM801 (see picture number 2, 10) to see if it is open.
Check those 3 caps, and need P/N of that IC (mounted on the heatsink) for driving the 12v/24v transformer, I have a feeing that the IC is bad.

[roadstir]

Re: Sun 24.1 LCD / Samsung 244T

Photos of both sides.

[roadstir]

Re: Sun 24.1 LCD / Samsung 244T

Bud,

Here are the pictures you requested. Let me know if you need any redone. And thanks for explaining the Hot & Cold side for me.

Jet, good eyes. Yes, it looks as though he replaced the cold side caps with Nichicon (5 of them), but nothing on the hot side.

When I asked the cap repair person if he checked the board after replacing the caps this was his reply: "We do just replace the caps and check those components to ensure they are installed and working properly. As for the power supply itself...that board is the power, and it does get power, so the board is working properly..."

Thanks,

David

[jetadm123]

Re: Sun 24.1 LCD / Samsung 244T

The main thing that caught my attention in that link I sent you was the fact that not all the caps were replaced. Looking at your board, I noticed that one of the caps had a black mark (from a marking pen) on top of it. Typically, this is something done at the factory and leads me to believe that not all the smaller caps were replaced. What brand is this cap? CapXon? Sounds like the repair person used Nichicon caps. Other than the large 100uf CapXon cap, are there other non-Nichicon caps? I'm thinking especially the smaller caps. Hopefully it's something as simple as the startup cap for the 24V section that needs replacing.

As mentioned above, the PFC section is functioning and it looks like the secondary section for generating the voltages at the wiring harness is not working. The 24V section of the supply is what the other voltages are derived from.