Gateway LCD FPD1830 flickers

On Sat, 26 Jul 2008 11:01:27 -0500, bob urz put finger to keyboard and composed:

I see several posts that suggest that replacing those 4 caps fixes the flickering problem. Why not just replace them anyway?

- Franc Zabkar

Are you sure all the lamps are turning on? Most inverters will shut down if one lamp fails to start. This is usually caused by the inverter, but a broken lamp will also cause it. Andy Cuffe

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When i get another parts order in i may just do that.

Visually, the caps look fine. No bulges, no leaks. ESR looks good in circuit. The other monitors i have fixed showed obvious ESR problems or bugles and leaks.

I started to draw a schematic, buts its going to take some time. It drives three lamps with one inverter and three lamps with the other. Both are controlled by the same OZ controller chip.

Bob

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On Fri, 01 Aug 2008 00:11:36 -0500, bob urz put finger to keyboard and composed:

One post suggests that those 4 caps are connected in parallel. If so, then an in-circuit ESR test may be inconclusive, as one good cap could mask three bad ones. Is it possible that the supply to the inverter is bad, in which case you may want to check the caps in the main PSU ???

The O2 Micro web site doesn't have any datasheets. It seems they are only available to O2 Micro's "partners". All we mere mortals get is a brochure with a skimpy "application diagram".

Having said that, you may still be able to get an idea how the OZ devices work by referring to the US patent at the bottom of each page.

For example, the description of the OZ9921 part refers to US patent #7,057,611.

- Franc Zabkar