I have built in a brand new FB4 in my existing RGB laser projector. It is working perfectly and I am very happy. I must admit I was a bit nervous at first, but the installation was amazingly straightforward. The most tricky and time consuming part was making a nice opening in the laser's housing but that went quite well eventually. At this time, I have two questions if I may: 1. I have noticed the ground wires are missing on FB4's galvo connector. For the time being, I have therefore left the GND connection on the galvo driver open and it is working flawlessly. I guess the wires are missing for a reason, so is it ok if I leave the GND-connection open? Alternatively I could ground the amp through one of the other connectors. 2. The safety switch section on FB4's (preliminary) manual says the key switch/emergency switch should switch off the power to the laser drivers. The way it was in my laser was that it switched off the modulation signal, not the power. I can imagine that in case of a severe malfunction, a laser unit could still produce dangerous output even when there is no signal present. On the other hand, I can also imagine that a laser driver continues for a short time when power is removed because of decharging capacitors etc. So cutting of 230V (this will need a relay, but that is no problem) is still the way to do this? A few things maybe to consider for future FB4 versions: 1. It would be nice if the wires for the color channels and scanners would be color coded. Now they are all black. I know there are not that many on each connector, but still. 2. The wires could be a bit longer. It's always easier to cut a few inches off than to add extra length. Especially the wires of the optional dmx module are very short. 3. I would prefer if FB4's front plate was a bit larger so you could choose to build FB4's front plate behind or before the projectors metal case. 4. I would prefer the network connector on the back of the FB4, so I could connect it to a robust Neutric connector. Actually, the best thing imho would be to produce two FB4 versions: one the way it is right now for compact projectors, the other XL with a larger front plate and network connector on the backside. Otherwise: job well done Pangolin. This is truly a great invention and well worth the money.