Converting a L3 11769 tube into 10160 format
I received some questions after uploading the latest video (below) which showed how to convert an L3 11769 (aka F9815) image tube into 10160 format. I took it out of a PVS-14, removed the pigtail, and installed it into an Anvis 9 non-gain housing (same process as the RNVG / DTNVG / Sentinel). This post is to answer some of the questions I got and give some more info.
BLUF (bottom line up front):
If you have a PVS-14(s) with L3 11769 removable gain pigtails, you have many more choices for binocular housing options to re-use the tubes in because most do not have gain control. If you're shopping for used PVS-14's, I'd recommend going for one that has a newer L3 11769 in it.
Tube formats 101: MX11769 (F9815) and MX10160 (F9800)
These are the designations for the two most common image tube formats. Another common tube type is MX10130 but it doesn't apply here because it is used inside the PVS-7 and is not interchangeable with the others. Most people, including myself, just use the numbers 11769 & 10160 leaving out the MX or using F9815 / 9800.
The 11769 is also known as F9815 and has gain control. Gain control meaning that you can manually adjust the maximum gain ( or brightness) level by a knob that's located on the night vision device housing. It's used primarily in the PVS-14 but also in other devices like the PVS-31 that have gain control. The gain control works through a ribbon cable, commonly referred to as the pigtail, that is attached to the tube and goes to a circuit board in the battery compartment or inside the device.
The 10160 (aka F9800) does not have gain control. There is no gain pigtail. It has a fixed static maximum gain level and is commonly said to have "auto gain control", which is simply the ABC (Automatic Brightness Control) standard feature in all gen 3 image tubes including 11769s. This is the most common tube for aviator's goggles like the Anvis 6/9 and is also used in many dual tube (binocular) goggles such as the RNVG, DTNVG, Sentinel, and other systems that do not have gain control functionality. However, you can stick a 10160 into a PVS-14 or other gain control housing and it'll work just fine. The gain control knob just won't work.
The way ABC works, is when you look from dark to bright, the tube will internally dim or lower the brightness to compensate. It isn't really "auto-gain" as it sounds, if that makes sense. It doesn't work the same as the gain knob and in fact the ABC can sometimes drive you crazy. As an example, let's say you're in a dark area with bright lights in the background and you're trying to look at something in that direction, the ABC can dim the image enough to make it hard to see. But it does work.
Why would you convert a 11769 into 10160 format?
The #1 reason to do this and why I did it, is to take an already existing 11769 image tube from a PVS-14 housing and install it into a binocular or other housing that does not have gain control functionality. This doesn't actually turn it into a 10160, it just turns it into 10160 format, meaning no-gain control. Actual 10160 tubes typically have better optical quality and are easier to collimate. This is because they're mostly used in aviator systems.
The advantage of these L3 11769's with removable pigtails is that you can use them in multiple types of systems with and without gain control. 11769's with non-removable pigtails, such as ITT, Photonis, and older L3, can only be put into housings with gain control and those options are very limited. I've used mine in different PVS-14's, Anvis 9, Sentinel, and will probably stick them in more housings in the future. Being able to use the tube(s) and the optics from a PVS-14 saves considerable money because you can buy just the housing minus the image tube(s) and optics. As an example, a new RNVG with tubes will cost at least $6,000, compared to around $1,500 for the housing itself.
How do you do it?
If you're new to intensifier tubes, it is critical that you understand which end of the pigtail you unplug. The end you unplug to turn it into 10160 format is the end that is directly attached to the tube itself. It goes slightly underneath a sticker on the tube. You simply raise up that part of the sticker to access where it goes in and carefully pry it upwards from underneath so it comes out. The other end of the pigtail has 4 prongs that go into a circuit board in the battery compartment. These are also "unplugged" or removed from the circuit board in order to remove the tube from the housing. Watch the video.
Is it safe for the tube?
It is 100% safe to remove the pigtails on L3 11769 tubes that have removable pigtails. I have confirmed this with a source at L3. The tube is designed to operate with the pigtail removed and will default to a safe gain level. The only risk involved is if you man handle and damage the pigtail. This matters if you'll ever want to use it in a housing that needs the gain pigtail. You'd have to be almost negligent in how you remove it to damage it. It's not difficult and worse case you should be able to buy a replacement pigtail.
Older L3 (approximately pre 2012 but possibly older) and all ITT and Photonis 11769 tubes have soldered on pig tails which DO NOT unplug. Visually inspecting it up close, you'll be able to see if it's inserted into the tube or soldered in place. The only way to turn one of these soldered pigtailed 11769's into 10160 format is to de-solder the pigtail from the tube or cut the end of the pigtail where it goes to the board, and solder in a resistor so the gain is at a safe level. The best out of the two is to de-solder from the tube itself and solder on a surface mount resistor. If you don't do this you will damage the tube. I won't go into details on soldering the resistor or the resistors but the info is in the public domain. I recommend going through a dealer/builder with experience doing this type of work. Try at your own risk.
Are there any downsides?
The only downside is that this will void any warranty whether through L3 or the dealer you bought it from. L3 typically offers a 2 year warranty on brand new image tubes and some dealers offer up to 10 years. I had a 10 year warranty on the devices & tubes but decided to go ahead and void it due to my experience with the many tubes I’ve had that never failed and that it’s rare for them to just suddenly die. I did run them for several months before doing this. It is a big risk I took no doubt but I love the tubes (high spec filmless WP) and wanted to keep them.