Schematic for IP-45130A (BN44-00127)

[MDOC]

Anybody have a schematic for the power supply board found in Samsung's SyncMaster 226BW and similar model LCDs? The model number for these boards is IP-45130A. (BN44-00127x is Samsung's number for this board, with x = F or C and maybe other letters.)

Thank you...

[retiredcaps]

Re: Schematic for IP-45130A (BN44-00127)

Anybody have a schematic for the power supply board found in Samsung's SyncMaster 226BW and similar model LCDs? The model number for these boards is IP-45130A. (BN44-00127x is Samsung's number for this board, with x = F or C and maybe other letters.)

What is wrong with it? I have this monitor sitting upstairs. I got it for free and for me, it was a simple recap.

[MDOC]

Re: Schematic for IP-45130A (BN44-00127)

Two monitors, both 226BWs used in dual monitor configuration, need new caps. I already just fixed one of them, having just received my order for new caps. C110, C111, & C112 show signs of bulging and did not pass ESR values (too high). I replaced all but the big 450v cap. The only old cap that passed ESR is C107 (47uF). These were CapXons. The new ones are Panasonics.

I wanted schematics so I can document oscilloscope displays between good & bad monitors.

[retiredcaps]

Re: Schematic for IP-45130A (BN44-00127)

I wanted schematics so I can document oscilloscope displays between good & bad monitors.

Try

http://elektrotanya.com/

[MDOC]

Re: Schematic for IP-45130A (BN44-00127)

Try

http://elektrotanya.com/

Joining that site was denied, it's by invitation only. But I have another member-only source of which I'm a member, I've sent an email about it. Thanks...

[budm]

Re: Schematic for IP-45130A (BN44-00127)

You can download 2 max per day if you are not member.

[MDOC]

Re: Schematic for IP-45130A (BN44-00127)

OK, I did a search on ip-45130a and bn44-00127 and the search term was not found. But you know what? I think I found a substitute schematic with the right reference designations for caps on a different model number.

[retiredcaps]

Re: Schematic for IP-45130A (BN44-00127)

4 service manuals, but I did not download any so I don't know if they have schematics or not.

http://elektrotanya.com/?q=showresul...oria=&kat2=all

[MDOC]

Re: Schematic for IP-45130A (BN44-00127)

They do have schematics, but none for the IP-45130A power supply/inverter board. When I saw that, I muttered, "Incomplete documentation." All they have is a reference to an "IP board." That's the one I want. I learned that the term "IP" is an acronym for "internal power".

[jetadm123]

Re: Schematic for IP-45130A (BN44-00127)

Even when they do supply a schematic, many times it's different from the power supply that's actually in your monitor. This is because all the manufacturers have a tendency to use different power supplies in the same model monitor.

[MDOC]

Re: Schematic for IP-45130A (BN44-00127)

Well, now I'm back (I was away on a retreat trip). 5 days ago I poked around on the logic board on my second SyncMaster 226bw monitor with the flashing backlight syndrome in order to document the anomaly, and the power supply board (not the logic board) died on me: no flashing backlights, dead screen. I believe it's something before the 13V output on the power supply. I have since replaced the caps with no improvement (and I half-expected that). My other monitor (also a SyncMaster 226bw) is working fine after a cap replacement.


With the scope on R106 on the board (the 13V output side, the resister is at bottom left corner of the above photo on the power supply), this is what it looks like: first photo of a squarewave decreasing in frequency in 2 seconds to the frequency shown in the 2nd photo (both photos shown below):


Above: the starting AC ripple frequency when it snaps in from 13vdc. This is the AC ripple riding on top of the 13vdc level, the amplitude is 0.1v/div in this shot and the 2nd shot following. The timebase is 5uS/div.


Above: the ending frequency of a squarewave before it snaps back to DC level.


Above: one-second camera shutter exposure showing squarewave decreasing in frequency before it snaps off (13VDC level) for 7 seconds, then another 2 seconds of squarewave, then back to DC for 7 seconds, so on. The amplitude here is also 0.1v/div with the same timebase noted above.

[MDOC]

Re: Schematic for IP-45130A (BN44-00127)

Perhaps PlainBill would like to comment, too.

[budm]

Re: Schematic for IP-45130A (BN44-00127)

When you deal with high frequency and use the scope to look at the wave form, you will want your scope ground lead as close as possible to the ground point of what you are measuring, otherwise you will get false reading due to impedance of the ground, 1" inch of trace can have high impedance due to high frequency. You should put the ground lead right on the negative leg of the cap. You can verify if you are getting false reading by attach the ground lead of the probe to the tip of the probe and see what you can see on the screen when you move the probe around, that little loop will act as sensing coil.

[MDOC]

Re: Schematic for IP-45130A (BN44-00127)

That's true, but that has no bearing on the problem.

[budm]

Re: Schematic for IP-45130A (BN44-00127)

Well, since the power supply is an always on power supply, you can disconnect the logic board and see if the 13V is steady.
If it is still bad, then lift up one leg of the green fuse for the inverter circuits, this will remove the load from the power supply.

[MDOC]

Re: Schematic for IP-45130A (BN44-00127)

Oh, the 13v is there, all right, whether you disconnect the logic board or the inverter circuit or both. It's just that the ripple is there, too, and I thought that shouldn't be there. The ripple is 0.2v p-p.

New development:
1) sawtooth waveform, picture shown below. This snaps into the squarewave I discussed earlier. Is the sawtooth normal?
2) I noticed now that some parts on the logic board like IC705 C744 C722 L703 are quite hot enough to burn you. Not normal. Appears to suggest I'm wrong about the power supply board being faulty. Any other suggestions? Thanks for the help.

What should the DC voltage across the big cap C105 on the power supply board be? I'm getting almost 170vdc out of it.

Below: sawtooth waveform riding on top of 13vdc. Amplitude is 5mV/div at 2 mS/div time.

[budm]

Re: Schematic for IP-45130A (BN44-00127)

That is only 1.5% ripple (The ripple is 0.2v p-p), it is fine for inverter supply. The saw tooth waveform is normal, it showing the cap is charging and discharging.
The 170V reading on the main cap is correct, it is the line voltage x 1.414 (you can ignore the 1.2V Vf of the two rectifier diode).
"IC705 C744 C722 L703 are quite hot enough to burn you" the caps should not get hot.
You can force the backlights inverter to turn on by putting a resistor (2.2K) between the 13V (this power supply board does not have 5V output) Line and the BL_ON LINE (the logic board will have to be disconnected so the we do not flow back into the main board)

[MDOC]

Re: Schematic for IP-45130A (BN44-00127)

Where is this BL_ON line on the power supply board? Are you talking about ON/OFF at pin 9 of CN2 connector which connects to the logic board? If so, that's 3.3V from the logic board. But if not, can you provide another ref on the board, such as a resister or other component junction with BL_ON? Or are you referring to enabling the inverter controller (OZ964GN) via pin 3 (ENA)?

[MDOC]

Re: Schematic for IP-45130A (BN44-00127)

Well, the last monitor's fixed and working. There was a short on the main board (I called it the logic board earlier). I replaced it rather than trying to find the short, since the replacement was cheap.

Initially, both monitors were exhibiting rapidly flashing backlighting. This was caused by capacitors drying out, and I replaced those. This fixed my first of two monitors but the second monitor developed another problem, probably caused by my unsteady hand probing the main (logic) board with a scope probe. I wanted to document the anomally.

The caps were made by CapXon. I replaced them with Panasonic.



Above: The flashing backlighting was caused by these caps.


While troubleshooting around the main board, I found that the schematics from the Samsung service manual for my 226BW monitor were the wrong ones, though I had specified the correct Samsung model number. Two things support this fact: schematic is different from what was actually on the board, and some parts are not in the parts list.



Above: showing part of the schematic I was working with before I discovered it was the wrong one.



Above: The correct schematic now has a schottky diode (D702) where the previous one didn't. And it wasn't listed in the parts list.


The cover page of one service manuals listed more chassis and model numbers than the other, but my monitor model number (226BW) was included in both. So I thought the schematic from both were redundant. I was wrong. In fact, schematics and parts lists are different, yet the copyright date from both manuals are the same!



Above: from the "wrong" service manual.



Above: from the "correct" service manual. Same copyright date but different text.


Anyway, in my previous post, I showed a pix showing sawtooth pattern waveform. After fixing my monitor, I took another look and saw a different pattern (albeit somewhat similar). This is not to say that the sawtooth was incorrect, only to say that the sawtooth was not a normal waveform to expect from a working monitor. The sawtooth is what you see if the main board is either not working or disconnected from the power board.

Below is the normal waveform riding on top of the 13V.

Above: Note that the frequency is a little different, too. Same scope parameters as the sawtooth pix in the earlier post. Scope input was on AC, not DC.



Above: where the waveform was monitored on the power board. I discovered that the two heatsinks on the board are tied to ground, so this was a better place to put the ground clip than on the corner of the main board.



Above: Ripple from the ON/OFF on pin 9 of CN2 on the power board (refer to previous pix for location). 0.1V/div 50uS/div, scope input set to AC. This is the 5V from the main board.


Below: my two monitors are now working.