Hello to all and PM25 with Scanpro20's

[stanwax]

The images were all legable but quality is a bit off at the moment. With the likes of scrolling text the letters are quite rounded at the corners and there are gaps between the start and the end of were the letters are scanned. will this be resolved if I use deferential signals. The PM25 has a set scan rate of 18k and can't be altered. Will post some picks of images ASAP.

Hi Carl
I would like to wait to see your images before I pass full judgement but what I will say is I have found the tuning of some of the chineese scanners out the box can be....lets say 'variable'. Particularly where the ilda tp is concerned, often it wont be displayed well at all and yes letters in particular can suffer. Unfortunately you cant expect much time spent tuning for the money they cost but the good news is that they can be made good. See attached image which is of the ilda tp displayed on a set of scanners the same as yours that I have tuned to 20k - it didnt take me hours and hours, maybe 30min or so and it looks pretty damn good - the bends you can see in for example in the right hand vertical line are due to the towel I was using as a 'projection screen' (you know how important it is to always know where your towel is...). As promised I will happily apply this tune to your scanners at the meet - in fact best will be if I show you what to do on the first set and you follow suit on the second set. And to answer your question I doubt there will be improvement if you go for differentail input - I reckon its scanner tune thats your issue.

I also tested the analogue blanking with my new CNI 150mW laser heads and I think I may have a problem with the lasers. When I press the shutter button on the desk to open the laser comes on but I have noteist that the cooling fan on the control board for the laser slows down and the beam power comes on but quikly dips. when I hit the shutter again the beam goes off and the fan picks up speed. Dose this sound like the switch mode power brick (that came with them) is not putting out enough amps.

I would agree with Frank, test the volts and preferably current draw at the point where power goes onto the driver board to see if its pulling too hard. Those power packs that come with CNI lasers are normally good for 4 amps and if that head is pulling near that I would say something is wrong. Even with the Tecs working hard I would only expect to see it blip to 3amps or so occasionally. The fans often change speed as the laser comes on but it should just be a subtle change of tone rather than a real drop in speed so I would monitor the 5V input - the heatsink fan on the CNI will be a 25mm 5V jobbie.
If operating the laser normally without blanking to the desk connected, ie just turned on in CW mode - what does the output do when you first turn it on? do you get the same dip in brightness?

Rob

[buffo]

Say Rob;

I've got a 100 mw DPSS blue that pulls nearly 4 amps from the 5 volt PSU. So if he's running a 150 mw blue, it could very well be pulling more than 4 amps. The PSU that came with my laser was rated for 6 amps at 5 volts, and I've seen them rated for up to 8 amps.

Adam

[stanwax]

Adam
I know lots of the OEM power supplies are 8amp & im not gonna argue with you - it just would seem a little high to me if its pullin that much - the meter will tell the story!

Rob

[frank_1257]

Many of these switching supplies suffer serious derating if even 10-20 degrees above room temperature or 100 degrees farenheit, overkill or good air flow is very important.

[Carl B]

Adam, Frank & Rob

Thanks for your input to my problems. With regards to the scanners, if differential signals are not going to improve the quality of the images much then I'l stick to single ended as I've aready cliped the signal this way with 20k trimmers and hope a retune of the amps is the answare.

The lasers are 150 mW 532nm units. Rob, the lasers don't work with out a signal on the modulation input. No CW option. The fan on the control board heatsink dose change tone when the laser comes on but no significant change in speed. May be I'm fretting over nothing but it just seemed not normal. Will try and get a metre on the laser PSU and try and post those picks tonight. Don't no if it's the asware but was looking at a 5v 7amp switch mode unit at CPC.

Remind me agian Rob. How far dose your towel move when traveling though hyperspace?

Thanks again.

Carl

[stanwax]

Don't no if it's the asware but was looking at a 5v 7amp switch mode unit at CPC.

It will only be the answer if the power supply you have is too heavily loaded - get the measurements done and then decide.
As for CW I meant if you connect up the ttl to 5v (not using the desk) to put it in CW mode (which will be recommended to make the measurements) does the power fluctuate then. Also if left in CW mode for say 10-15 mins to fully warm up does the problem of it dimming still happen. It may be its peaking way over the 150mW and quickly settling down to the desired value - only a power meter will tell you and again we can measure this for you at the meet

Rob

Remind me agian Rob. How far dose your towel move when traveling though hyperspace?

[Carl B]

Hi Rob

Befor reading your last post I did some tests tonight but it was with my desk. Unloaded the power brick puts out 5.21v and with the laser on full power the volts drop to 5.13v. This was with a patern with no blanking. When I tryed the laser with my old TTL blanking DMX system again with no blanking, the laser was doing the same thing and it dose still peak then dip off after running for more than 15 mins, so as you say it must peak then quickly settel down to normal. Just need to see if two lasers are happy running off the one analogue blanking signal now. I'm now itching to start installing my kit into the new cases.

How far you move from your towel depends on how far you have traveled though Hyperspace I think. Have to look it up to reminde my self.

Carl

[Carl B]

Here are the photos of the PM25 scanning some text with my ScanPro20 scanners. Photos not great. sorry.
Attachment 2889

The next two photo's are of some random letters. X T C Y W
Attachment 2890
Attachment 2891

I also got to try both my CNI lasers together and they were quite happy using the one blanking channel from the desk. The dimming of the lasers was smooth from very low to full and both start lasing between 25 & 30% on the desk. I have noticed one laser is putting out more power than the other. They were both sold to me and labeld as 150mW units. Still under warranty if one has to go back.

Carl

[stanwax]

Carl

do we Know what font that is? and what sort of scan angle was it at?

Rob

[Carl B]

The text line was scanning at about 500mm across from about 2.3M. Don't know the exact font but is like this Verdana font. Still useing single ended signals. Hope this helps. Must get round to printing that scan angle chart of your's. That would help.

The TP photo looks good and gives me hope that my scanners are up to the job.

Carl