Distorted DT's
I have 3 projectors with DT40 Pro's in them, currently all connected to the same DAC (QM2000 Pro). Two have the new silver Galvo sets and one has the older black type, all have large 5mm aperture mirrors and the drivers have notch filters which I haven't touched... They are all tuned to look identical and scan at the size set by the factory, all are tuned to at 30k. The test patterns are being scanned at 30k and a measured 8˚...
The two silver sets are perfect, but when I start the projector with the older set (which is first in the chain, so directly connected to the DAC), the image is awful. The circle is an oval, it touches the square top and bottom, but not at the sides. The main white square has no sharp dots at the corners, the green square shows undershoot on the Y axis and the five lines underneath the square all turn up on the right hand side as you look at it. (Sorry, tried to get pics, but my iPhone doesn't like it, once my proper camera charges I will try again). Thing is, after a 5 minute warmup period, I have a perfect set of test patterns (ILDA, Orientation, Damping Grid, Lasermedia etc).
Everything points to this being damping issues, but again, after 5 minutes, the grid test pattern (for setting damping) is perfect.
Any ideas what is causing this to happen and more importantly, do you reckon my scanners will be ok if left like this?
By the way, I have a fair bit of experience with tuning scanners, ScanPro's, ScanLSP's, DT40's, widemoves, I even managed to get a good test pattern out of a set of Laserworld scanners...
Any insight greatly appreciated.
Mark
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