12mm Box Wrench Hemostats Exacto Blade Focusing Chart Kapton Tape Toothpicks Replacement IR Filter 12v Power Adapter Sensor Safe RTV Glue (*Not pictured) Not Pictured: Video output monitoring solution of your choice Optional: Isopropyl Alcohol
*NOTE: I have learned something new about RTV glue and discovered that the glue shown in the picture should not be used. You should use “Sensor safe” RTV glue instead.
On this particular job a number of substitutes would work well. Instead of a 12mm box wrench, an adjustable crescent wrench or slip-joint snub-nose pliers would work fine in a pinch. Standard packing tape could be used in place of Kapton tape, nothing the tape comes into contact with is static sensitive but it’s the “right” tape to use in electronics. You could use most any small stick shaped thing to apply glue, it doesn’t have to be toothpicks. There are a number of ways to power the PXL while it is open and on the bench, if you don’t have a 12v adapter you could wire in a 9v battery clip temporarily.
Lastly, I’m not totally convinced that RTV glue is what they originally used in the PXL. In fact I’m fairly certain it isn’t. But, it looks very similar, it has a rubbery texture when it dries like the original, it is removable like the original, and most importantly it stays in place and does not drip or creep. It is silicon based, and I believe the original glue was also silicon based. There are certainly other glues that would work, but many come with aforementioned downsides. I looked at a lot of different options and didn’t find anything quite like what I found in the camera. If anybody has an idea of what glue was originally used in the camera, or has thoughts on what a better glue to use would be, do not hesitate to get in touch. I am always happy to update the tutorials to be better or more accurate. An untested theory I have is maybe it’s some kind of silicon caulk?
Prepare 2 pieces of kapton tape, use the wrench to unscrew the Lens assembly, then immediately cover the CCD sensor, then the aspherical lens. You do NOT want dust on the CCD. It is a complicated and touchy surgery to remove it.
The lens assembly consists of 2 main parts, a lid and a bottom, connected with retention clips. We need to remove this lid in order to access the IR Filter. My method is to place the assembly on the table, IR side down, and use my thumbnail to release one of the tension clips, then the 2 halves should be loose from each other. It’s not easy to get a picture with my thumb in the way, so I used a screwdriver to point to the clip. Using my thumbnail in this way has proved to be the best way to control the release of the clip, using a tool is liable to slip or damage the plastic.
And now we have access to the IR Filter. Here is where your journey will vary. One camera I opened had the IR Filter just fall right out. Another camera I opened, the IR Filter was a little stuck, but ultimately only needed a little coaxing to remove. The last camera I opened the filter was so stuck in place it got chipped as I tried to remove it. Literally all 3 cameras I opened up that had a filter in them had 3 different levels of stuck-ness. So, cross your fingers for a loose fit here.
If yours is stuck, the only tool I’ve found that fits in the little corner there is an exacto blade. You need to be very careful here, you want to use the back of the blade to contact the glass, not the sharp side. When you use leverage, you want to use it on the SIDE of the filter, do not attempt to pry the corner, it will chip. When applying pressure, you want to apply more sideways pressure than upward pressure, and as you do so, “hinge” the filter out of place like it was a door. If you’re really careful, and you’re really lucky then hopefully it should loosen and come out in one piece. Good luck everybody!
There’s not too much going on in this step. Use Hemostats to drop the new filter in place, then snap the top of the filter on. The filter snaps into place only one of 2 ways. Make note of the little posts, and their corresponding holes. Then, just snap it all back together.
Be careful not to touch the replacement IR Filter with your greasy fingers. If yours is dirty or oily, it’ll clean right off with a quick rinse in some Isopropyl Alcohol. If you got your filter from me I use Hemostats to package all the little bags so they should be clean, but it never hurts to give them a rinse in iso anyways.
So before we continue with focusing, it’s possible you got lucky and can skip the next step. Most PXL’s appear to be focused perfectly fine out of the box, and in some cases, the adhesive will break off in a favorable way so as to maintain the adjustment depth. The above picture illustrates just such an occasion, and if you screw this lens all the way down, it’ll be at the same focus as was set at the factory, which appeared to be perfect. It’s still a good idea to test it against the focus chart just to be sure, but you might be able to skip a few steps.
Now it’s time to screw the lens assembly back into the CCD housing. Start by removing the protective tape from the CCD and lens assembly, and set one of them aside for use later. When reinstalling the lens assembly, the best practice is to place the parts together, turn the lens counter-clockwise until you hear a click, THEN you proceed with clockwise threading. That way you know you’re at the start of the thread pattern.
Be VERY careful not to cross thread the housing, the thread pitch is very fine, the plastic is very soft, and it is very easy to get this wrong. If you feel resistance, STOP. back it out, inspect the threads, and try again. You will know when it is threaded properly, it should turn easily.
At this point just get the thread started with a few turns before we move on to the focusing step. If you got lucky with the glue and you think you don’t need to focus your lens then go ahead and screw it down until it stops.
In order to focus the lens you’ll need to power your camera and set it up to a video output while the case is open. It’s not possible to use the standard AA batteries in this configuration, so using a 12v AC power adapter is easiest. If you don’t have a 12v DC adapter, you could alternatively use a 9v battery and battery clip soldered to the AA power input (AA batteries are 1.5v each, x6 = 9v).
Note: If you have never used a power adapter with your PXL before and you’re looking in a bin of adapters you have sitting around, take note that the PXL-2000 has a CENTER NEGATIVE 12v input plug. Most AC adapters are sleeve negative center positive, and will fry the power input if you connect them. You can make one of these adapters work, but you’ll have to swap the leads around. You can easily do this by using a lineman splice and some shrink tubing.
Insert a cassette, and place your camera approximately 6″ / 15cm from the focus chart. Plug in your chosen methods for video output and power, press the rec/play buttons, and now we move to the video monitor.
Above I’ve put together an animated gif to give you an A/B comparison and help illustrate what a properly focused camera looks like. Below, I will also include static images for reference.
Some things to look for:
In the out of focus image it’s pretty clear that the image is blurry. The outside of the arms are completely rounded, and no sharp corners are discernible at all. The inside of the circle has a light grey haze to it with only faint indications of separate lines and a darker grey dot in the middle.
The soft focus image shows clear improvements in the sharp corners of the outer circle. The pointy barb however, is still fuzzy and barely distinguishable. The light grey circle at the center is smaller, and the small dark grey circle in the very center is darker than in the out of focus image.
It’s a bit hard to determine “tack sharp” on a video format that’s inherently so lo-res that the resulting image is pixelated, but the in focus image has some pretty clear litmus tests so you can know that you’re perfect. The outer circle clearly shows very sharp corners, and the barb is also clearly visible and distinguishable. The center of the circle still has a black dot, but the pixels surrounding the dot begin to show an almost tessellated pattern. The nice thing about the PXL being lo-res is that you have a decently wide range of adjustment that will produce a perfectly in focus image, so don’t agonize for too long about it.
Use one of the pieces of tape you set aside earlier to hold the lens adjustment in place while you glue it. Prepare a dab of RTV glue on a toothpick, and glob some on there. There’s really not much to it. Don’t be shy with the glue, make sure you push it down so that it has good contact with the threads as well as the housing and you should be good. Let the glue dry overnight. Once dry, remove the tape, give it a gentle test, and if needed you can apply some more glue. It won’t be rock solid, RTV glue dries pretty rubbery so it will have a little give, but it should be enough to hold the small parts in place.
If your lens is focused and the glue is dry then you’re done! go ahead and continue with your project or put it all back together and start recording!
