Cheap Chinese laser - teardown w/ pics

[james]

Make a simple frame like a big white circle in both software's a use a volt meter to see what voltages appear on what pins.

Pins 5, 6 and 7 on the DB25 are R, G, & B.

[A1pyro]

I bought a RGB 1.5 watt Chinese laser also except everything works great on it except the red has a thick beam, I tried to turn the lens some to get it to focus to make the beam smaller and tighter but their lens they use sucks. It won't go any smaller and just goes from thick to thicker and there doesn't seem that there is anything I can do about it. I called the manufacture and they said that is the way it is suppose to be. BS. when making something using white, purple, orange etc. the red beam is so much wider then it should and looks like crap. It makes it almost useless. I guess that is what I get for buying Chinese crap.

[lilylin]

I bought a RGB 1.5 watt Chinese laser also except everything works great on it except the red has a thick beam, I tried to turn the lens some to get it to focus to make the beam smaller and tighter but their lens they use sucks. It won't go any smaller and just goes from thick to thicker and there doesn't seem that there is anything I can do about it. I called the manufacture and they said that is the way it is suppose to be. BS. when making something using white, purple, orange etc. the red beam is so much wider then it should and looks like crap. It makes it almost useless. I guess that is what I get for buying Chinese crap.

It was just one of your bad experiences.It can`t be concluded that all Chinese products are crap.At least,in this forum,many members bought lasers from China,and they really gave the objective reviews for what the got.I believe you will meet the right Chinese manufacturer.Good luck!

[skacutter]

Keeping this thread specific to the DY-868 and super QiQi.... The case is still open with ebay and qiqi says he is shipping me the LP-30 but I’m not too hopeful has the case has been open for 40 days now. Clearly the unit ships with the LP-20 installed. Qiqi was pointing me to some documentation on the web that detailed some modification to make the LP-20 perform at 30k speeds. You know guys this isn’t rocket science. The pangolin system with the Ilda test pattern does not lie. If you cannot maintain the circle within the square at 30 degrees (40 inch image 110” away from the projector) then the scanset is not performing at 30k. My best guess which I believe to be very accurate is that the LP-20 performs out of the box at 12k and can be tuned to 18k. It doesn’t ever perform at 20k and 30k is not possible with any mods to the lp-20

[White-Light]

Actually the ILDA specification is for 8 degrees for the test patterns.

If it can do the main ILDA test pattern correctly @ 8 degrees at 30K then its 30K.

Test the ILDA pattern at that angle against a wall and see what you get.

[skacutter]

sorry...100" from screen.... test pattern 14" wide... That’s 8 degrees and how I am testing. Yes I did misquote 30 degrees and 40" wide. However at 8degrees I get a sloppy circle outside the box and slightly oval. if I reduce the scan speed in software to 12k the circle is inside the square but the pattern is drawn with heavy flicker. 18k is about the best to reproduce basic images without major distortion. Are any DY-868 owners out there getting better performance then my projector? clearly the oem documentation rates the scan speed of the LP-20 at 20k. I’m sure that’s under ideal conditions and pushing the amps to the limit. It just kind of urks me that qiqi is still advertising on ebay at 30k and 1W and displaying the ILDA logo all of which I have pointed out to ebay is fraudulent. those are big jumps in price he demands for what is basically the same unit.

[alexi]

Funny Calculation.

Advertised Chinese Watts = real Watts * (sales budget / YTD sales) * this years lucky number

[buffo]

Sorry I'm a bit late to this thread, but I think you've got your thinking backwards when it comes to scan speed...

at 8degrees I get a sloppy circle outside the box and slightly oval.

Did you mean at 8K speed, instead of 8 degrees? Because if the circle is outside the square, this is a sign that you are scanning too SLOW, not too fast. To shrink the circle, you need to increase the scan speed.

If you really did mean 8 degrees, then at what speed did you notice that the circle was outside the square?

if I reduce the scan speed in software to 12k the circle is inside the square but the pattern is drawn with heavy flicker.

The flicker is to be expected at such a slow scan speed. But you want the circle to be just touching the sides of the center square. If the circle is already completely inside the square, you are scanning too fast and need to slow the scan speed down. But that doesn't make any sense if you're already down around 12K.

18k is about the best to reproduce basic images without major distortion.

That sounds pretty typical for a bargain set of Chinese-made 20K scanners. It could be that with a slight adjustment of the amps, you could get them to 20K.

However, this does not make sense given your statement above that the circle was inside the square at only 12K. If that's the case, then jumping up to 18K would have made the circle much smaller, and it would also start to pull apart into a spiral shape.

Have you ever tuned a set of scanners before? If not, you might be able to find someone here on the forum who lives close to you that would be able to help. Barring that, there's always my scanner tuning tutorial that you can use... (You may want to read that anyway, just to get some more information about what is actually going on with that ILDA test pattern.)

But based on what you've posted so far, the numbers don't make sense. You might want to clarify that first, before you try anything else. Assuming you simply wrote the numbers down wrong though, it may be that your scanners just need a little tweaking to reach peak performance.

clearly the oem documentation rates the scan speed of the LP-20 at 20k. I’m sure that’s under ideal conditions and pushing the amps to the limit.

If you've got the circle just touching the sides of the square at 18K and 8 degrees, and it's still a circle (and not an oval), then you're very close to their advertised speed of 20K. Probably a quick tweak is all that would be needed to get them there.

For the record, the ILDA test pattern (and indeed, any tuning standard) is always going to be "pushing the amps to the limit", since that is an integral part of tuning. It defines how the scanners will behave when they are ballistic (under constant, maximum acceleration), and it allows you to predict how the image will distort when you push everything as hard as it will go.

It just kind of urks me that qiqi is still advertising on ebay at 30k

Wait - was your projector listed as having 30K scanners, or only 20K scanners? If he sold you your projector as a 30K unit and you're only getting 18K out of it, then I'd say you have valid grounds to get a refund. But if he sold you a 20K unit and you're at 18K before you tune, then you probably don't have a case.

Another thing to conisder: if the projector is otherwise working just fine, you may want to consider simply changing the galvos out yourself. A set of 30k-capable scanners can be had for less than $150 these days.

That might be preferable to a long, drawn-out battle with the seller to return the projector you already have. (Plus you may be on the hook for return shipping charges, which could be enough to cover a good portion of the cost of new scanners.) Just something to keep in mind...

Adam

[skacutter]

Got a package yesterday from Super Qiqi. Its the LP-30 scanset. The LP-30 PSU is many times larger than the LP-20 and the amps are taller then that of the lp-20. I need to rework all of the components to get the PSU to fit inside the projector. A quick test with the lp-30's installed I can now reproduce the ILDA test pattern at 30k and its perfrect. I will post some pictures of the comparison between lp-20 and lp-30. Note on the hot glue.... in my projector thats epoxy and its not removable without breaking parts. also the white substance holding connectors together is indeed latex (I had joked about that since qiqi's main product line is kink and fetish wear).

The scanset has a sticker on each amp and each galvo detailing which is X and Y and the serial number. This is done because the amps are pre-tunned at the factory to the galvo it is to be used with.


some things I actually like about the design of the dy-868

compact for sure
Cooling fans well placed
built in media excellent when testing and swapping out parts
chssie is well built
amp location with all pots facing up ideal for tunning
galvo mount is solid

[skacutter]

LP-20 LP-30 Amps

PSU's LP 30 power supply is much larger

look identical

If you upgrade your DY-868 to the LP-30 the amps will mount with the existing holes for the lp-20. The power supply is a tight sqeeze. I moved the double stack PSU's that power the cooling fans and diode divers mounting the top supply on the rear wall of the projector. The LP-30 PSU has a bracket mounted to the laser plate and another using the old lp-20 psu mounting holes and it floats over the DMX driver board. The performance of the LP-30 is top notch and when scanning they sound much like my G120's do at 30k. LP-30 is rated 35k at 8° by the OEM.