Scanner Upgrade Help - DT-40W

[bungy]

I have a Chinese projector that I am attempting to upgrade the scanners in. This projector is for my personal home use only, and I am intending to eventually build my own complete projector. This is mostly just an excercise for me to get some experience.

This unit has 20k-ish scanners and I am trying to install a set of DT-40 Wides. I can't figure out what the inputs are on the original scanner amp, so I can't adapt them to my DT-40 amps. I realize this amp is probably non-standard, but I'm hoping someone with more experience might be able to see something I don't.

Here is a picture of the scanner amp. The connectors with X's are unused. I am concerned with connectors 3 and 4.
1. Power input - not needed for my upgrade as I'll be using a different power supply
2. Goes to the case fan - WTF?
3. This is labeled X and Y with a black (ground?) wire in the middle
4. From top to bottom it's labeled P, 5V, V-, GND, V+

On my DT-40 amps, I have inputs for -, +, and GND. As I understand, I should wire my inputs to + and - on each amp and leave GND unconnected.

Is the original amp non-differential? Can I still wire in my DT-40W amps?

[polishedball]

Just run new wire from the ILDA db25 to your new amps.

[bungy]

I figured I would have to run new wires from the ILDA input. I was hoping I could just use the existing wires and build a custom adapter.

[polishedball]

Just grab a meter and ohm them out back to the connector or DMX board if that is the case.

[bungy]

Now why didn't I think of that... good idea. Only thing is there's a show card between the connector and amp, not sure if there would be a direct passthrough. I will try it though.

[bungy]

None of the wires at the amp go directly back to the ILDA connector, so I added wires on X+, X-, Y+, and Y- at the connector for my new amps.

I installed the scanners and wired up the new PS and amps, and disconnected the old amp and fired it up. At first there was no laser emission. I reconnected the old amp and it worked as normal. However, the scanned image was very jittery and this turned out to be a grounding issue as I didn't have any of the new components mounted inside the case or otherwise grounded at all. Tying all the grounds (with test clips) to pin 25 cleared up most of the jitter, I'm sure a better connection will remove it completely.

40k is A LOT better than 20k! I felt this was a good learning experience and can't wait to get some analog lasers and do a proper build.

[bungy]

Well, I took it a step further with this projector.

When I disconnected the original galvo amp, the lasers behaved unexpectedly (red & green always on, and never any blue). So I wired the laser signal lines to the ILDA connector and I was able to disconnect the amp and all the other built in hardware. I didn't care for the SD Card functionality and the built in effects were pretty boring, so I really just wanted a straight ILDA projector and now that's what I have.

The other benefit is that I can now produce full power beams, the original hardware had some built in processing that killed the lasers if the scan angle went below 1º. That's not a great "feature" in my mind, but that's what I get for buying such a cheap device. My new galvos cost more than the original complete projector.

I was able to build an integrated external mount for the new hardware without modifying the original case. So I can always bring the unit back to its original condition if I decide to sell it. There was an extra channel on top of the case that I could slide in another piece of sheet metal and have some room for screw heads between it and the original top plate. So I got some 16ga sheet metal and angle aluminum from Home Depot and put together a basic bracket to mount everything on. Everything fits under the original mounting bracket.

The grounding is much better now and the scanned image is rock solid.