URGENT HELP NEEDED please!! Major problem on my projector right before an event...

[sbk]

Hi guys, I need some quick help to correct a major problem

Today I installed a new quad RED module (as in this post).

At home it worked nice, but I noticed a strange problem : the red was at full power if the ground of the power supply was touching the main board of the laser. So I disconnected that, and that seemed to work.

So, tomorrow I have an event with my projector, I installed the it and all that, but I noticed that RED laser was on full power all the time now!!! I discovered it was a strange ground loop between my portable computer and the projector. I corrected (temporarily) the problem by removing the earth on my portable computer power supply.

But some hours later, the problem reappeared by itseld, and nothing to do to correct it!!! I think it's a problem related to the new RED module and its driver (FlexMod N2), as before I never had that problem.

--- All the diodes are already insuled individually from the base plate ---


So I am really really annoyed now, I had to unmount my projector and take it back to home... Does anyone can help me before I return to the location tomorrow? I'll be infinitely recognizing!!!

[Laser Ben]

Put an isolation transformer in the projector.

[sbk]

I'm not sure it will work. The ground is going from my portable computer to the USB to the FB3, which go to the projector ground.
Maybe I should remove the earth or ground connection on the FB3, but don't really know why doing that...

[platinum]

You can also power your FB3 from USB, if that helps.

There's either a jumper, or a spot to solder one in. (two pins)

I did that with mine at SELEM last year after getting a phantom ground. Of course, you'd want your computer to be on the same circuit as your projector, ideally.

-Jonathan

[sbk]

FB3 was already powered by USB...

I think problem is resolved now Seems like all my diodes, the driver and my gain/offset board have just DIED

Hopefully, my green and blue lasers are still alive.

So I go to bed now, and tomorrow I'll have the choice between re-installing my old red or to suicide myself...

[drlava]

Hi, I posted this in your other thread..

sbk, very nice workmanship! I like the design. I can see that you isolated the diode cathodes from the casing with thermal pads, good but I see some gaps in the insulation at pressure points. Make sure that this hasn't shorted out for any of them. You can do a reistance measurement with the power off from the diode case to the mounts. Other than that, the driver operation is simple: mod- is the same potential as power -, the controller should drive mod+ from 0 (off) to 5V (full on)