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EL panel for taking flat field frames based on an old laptop TFT back light screen

When my first lightbox was starting to give problems due to moisture taking the best out of my drafting vellum, I stumbled on this very nice alternative posted by YesYes from the Stargazers Lounge Forum. Fortunately I had an old Packerd Bell laptop around that would provide an excellent donor for the back light needed to create a cheap DIY EL panel for taking flat frames. The main issue that needs to be solved when using a back light is to make work without a VGA signal source, as is also perfectly explained by YesYes. In short, you need to hands on the voltage signal used by the VGA card to make the inverter stay on. In my case this was acquired by just measuring the voltage of the different pins of the inverter board while the seperate components were connected up as they were when the laptop was still functional. I found that in my case I needed 3.3 V at the signal pin 3 or 4 (the other one is used for dimming the backlight), so I decided to put 3.3 V on both as this was also the case when  the laptop screen was running at full brightness. So I build a small DC-DC converter in order to provide pins 3 & 4 with 3.3 V, and pins 1 & 2 with 13.8 V (19 - 15 V in laptop on AC or battery respectively), leaving pins 5 & 6 as the mass. When this was all connected up, it works just like in YesYes's case, and costs hardly anything. Below are some snapshots of the components, the panel in action (testing) and the first result of flat fielding an image with this setup.


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