Re: Repairing a FujitsuSiemens LSL3230T

So I've been poking around with this board and I'm pretty sure I've narrowed the problem down to one of the two dual-package 60V MOSFET ICs on the Inverter Board/Riser Card (which can be see as the "wall" on the right half of the power board separating the inverters from the transformer.)

The story:

I began a systematic effort to try and test all resistors, diodes, semiconductors, and capacitors on the board. Obviously, testing some components while on the board can be tricky, but many of them can remain...

Re: Repairing a FujitsuSiemens LSL3230T

Resoldered all the components back on and here are the results:

Voltage across main capacitor: still 166.7VDC

With logic board attached, I'm measuring 1.67VDC on pins 1 and 2 of the connector.

With logic board disconnected, I'm measuring 3.0VDC on pins 1 and 2 of the connector.

Ground was taken to be one of the heat sinks on the secondary side (same potential as pins 3 and 4 of connector).

Also rechecked the switching MOSTFET. With my meter in diode test mode, applying voltage/charging...

Re: Repairing a FujitsuSiemens LSL3230T

Hi Budm, thanks for your help.

I've attached images of both the front and back of the power board. The backside of the board is from right after I desoldered the transformer, secondary side rectifying diodes and switching MOSFET for testing (so that's why those solder joints are not present). I also have some images of the transformer by itself that I can upload as well if you'd like to see them.

Any suggestions on what portion of the board/where in the circuitry would be the protection circuit? I'm taking a look...

Re: Repairing a FujitsuSiemens LSL3230T

Oh, another piece of interesting information:

I tried finding the HSG1067 service manual figuring that it would include part numbers. I wasn't able to find it, but in the process I stumbled on the LG Flatron W2234S service manual, which includes a schematic for the power supply that seems to match the HSG1067 very closely from the traces that I've followed, although I admit it's not exact.

In any event, the transformer listed in this service manual is:

[code]XFMR SW DIP ER28 PC40 650uH SPW-100 RoHS...

Re: Repairing a FujitsuSiemens LSL3230T

Bump!




Any luck on being able to identify this part?

I'm trying to repair a Hannspree HSG1067 LCD Monitor's power supply, which, from some of the surfing I've done, seems to have an identical power supply as the Fujitsu Siemens LSL3230T.

As DMCrimson indicated, a search for "SPW-134" over the net has yielded zero results, except for the reference made here. The markings on my particular transformer are:

[code]SPW-134
SBI 4.2 E156193
...

Re: New Members - please post your introductions here

Hello all the lovely members of badcaps.net! I'm happy to be here and hope that I can learn a ton of information from you all and hopefully be able to helps others out in the future!

I learned of this forum via some of my web surfing to try and restore an LCD monitor's bad power supply, and I also heard of you via the member Ramonetb!

I like to learn how electronics work, and I have had quite enough of power supplies being a black box! Conceptually, I'm understanding a whole lot more nowadays about...