Very Strange Problem

**andy_con** · 02-13-2010, 03:14

this one has me really really baffled??

ive just doubled checked the wiring and everything seems just fine.

got 3 lasers running on die4laser drivers, connected to a psu. before wiring to the psu i used a bench psu to set up the power, so when 5v hits the modulation i get full power on each laser. all working fine

i now have them wired to my psu, but even if the psu isnt plugged in, i add 5v to the modulation wires and each laser turns on. WTF

100% lost.

**andy_con** · 02-13-2010, 06:19

fooking PSU, fooking lasers, fooking electronics..............

suspect ive blown a few diodes as well now.

heres my psu, 240v in and 5v and 12 out. simple!

so obvious mounting place is the big metal heatsink with 4 holes in it.

so i used that to mount it to the base plate.

but oh no, that metal heat sink has 150v AC going to it...........
so bang 3 fuses blow and probably some lasers.
turn the psu over and for some unknown reason the heat sink is connected to the mains...

so now ive got to try find a safe way to mount this psu without making the whole case live with 150v

**loopee** · 02-13-2010, 08:13

Hey Andy

It isn't uncommon for switchmode power supplies to live heatsinks (usually they have stickers to identify this)

I always go for the enclosed models where ever I can just to avoid the situation of accidentally brushing against a live heat sink.

Being en ex-electrician I've had my fair share of shocks

I think you may find your laser in tact as long as the mounting plate was earthed (if not this is a good reason to do so)

Troy

**andy_con** · 02-13-2010, 08:20

Originally Posted by loopee

Hey Andy

It isn't uncommon for switchmode power supplies to live heatsinks (usually they have stickers to identify this)

I always go for the enclosed models where ever I can just to avoid the situation of accidentally brushing against a live heat sink.

Being en ex-electrician I've had my fair share of shocks

I think you may find your laser in tact as long as the mounting plate was earthed (if not this is a good reason to do so)

Troy

yeah it was earthed and just got everything hooked back up and everything seems to be working. so im pleased now

**allthatwhichis** · 02-13-2010, 08:54

Originally Posted by andy_con

yeah it was earthed and just got everything hooked back up and everything seems to be working. so im pleased now

...............

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