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Old 12-22-2016, 10:08 AM
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DavGoodlin DavGoodlin is offline
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Join Date: Aug 2011
Location: near Strasburg PA
Posts: 3,400
Samsung 32" LCD PS fail

I had two Samsung 32" LCD sets, both dated Sept 2008. One was given by a co-worker who bought another one. the other is from a friend who wants it back if I can make it work. These were sitting in my shop for 2 years while I worked on all manner of tubed stuff. Procrastination is my forte when it comes to newer-cheaper stuff. 'specially when I never worked on an LCD before.

The first one was super-easy, with an easily spotted failure on an obvious power supply board in the center of the set.
A short-fat 150 uf, 450 v Samwha cap that was bulged, baked and burnt. A replacement is longer but fit in sideways. The set powered up and scanned the OTA channels easily, only missing a few. This one will probably be used by the kids at the PC table, to play Xbox or some crap on it, since they helped me take out and put in the screws

The second one looked very different inside with a PS board on the right side, with the PCB plugged into the display back at 8 evenly-spaced connectors. The caps looked normal and tested most, which showed low ESR. When I removed it for cap tests, a small soot mark on the display back put me in the neighbor hood of the failure.

Maybe a whole board is available online. But it looks like two surface-mount Zeners made the soot. One was shorted along with two power tab transistors (?) mounted on a heat sink, both showing an E-C short. the model is a LN32A330JIN. The PS board is a Ampower model K02P128.00
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Last edited by DavGoodlin; 12-22-2016 at 10:12 AM.
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