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Recapping a Billabs BL27CB0P

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the_77x42:
After playing a few more games, I notice that I actually have VERTICAL linearity issues in 15KHz mode now. The centre of the screen is compressed where the top and bottom are fine. I had noticed this prior to the recent repairs as well.

I don't know why this only happens in 15KHz mode, but I'm thinking of just changing the monitor profile so that it only goes as low as 16KHz. That and above seems to have perfect geometry. Maybe there's something wrong with an IC? Maybe there's a coil or transformer that's out of spec just enough that it only affects that one frequency? I'm not sure. It seems like in 15KHz mode I either have horizontal or vertical linearity problems.

Without a schematic and without an oscilloscope, I'm happy to just Band-Aid it in software. I wish I went with a D9200 or similar all those years ago, at least I'd have better support resources.

EDIT: Wow, I fixed the vertical linearity problem with the PRO menu (hold MENU DOWN when powering up the monitor). It seems I am able to get that menu in 25KHz mode and that was the mode that had the worst linearity problems. What a ride.

the_77x42:
At the end of all this, I simply created a profile in VMMaker (part of GroovyMAME) with a lower bound of 16700KHz. At this resolution, all the geometry is perfect and I can get the pro menu. Aside from the geometry being fixed, there is no noticeable difference in the two modes. I'm calling it a win and a manufacturer defect.

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