Why did my 642nm diode die?

[catalanjo]

Never! A faint heart never won a fair laser!

Anyway, what am I worried about? I bet the old school guys hoping there beautiful gas laser doesn't get smashed in transit really had something to cry about when things turned pair shaped.

It was never a "smash" that caused the anguish, it was usually a tiny screwdriver or a pair of tweezers weighing a few grams landing right on the brewster with a tiny "click" then silently the tube would go "up to air"!

Best of luck with the next one!

Cheers

[dnar]

It was never a "smash" that caused the anguish, it was usually a tiny screwdriver or a pair of tweezers weighing a few grams landing right on the brewster with a tiny "click" then silently the tube would go "up to air"!

Best of luck with the next one!

Cheers

One thing I have always wanted is a time machine to rewind just 5 seconds... That is all. Rewind to just before the "oh fuck" moment.

[LaNeK779]

One thing I have always wanted is a time machine to rewind just 5 seconds... That is all. Rewind to just before the "oh fuck" moment.

can't you use NE 555 to make one?

[300EVIL]

Just out of curiosity,,, Do you have the correct pins selected on the LaserBug? I'd hate to see ya loose another one.

Good looking rig BTW...

[kitatit]

Just out of curiosity,,, Do you have the correct pins selected on the LaserBug? I'd hate to see ya loose another one.

Good looking rig BTW...

Hi Adam! thanks mate. I like to make thing visually easy to understand. If I was working on this while it was a rats nest of wires, I probably would have blown up more than one diode by now

About having the laser bug connected properly.... yes that thought has crossed my mind. I had a long look at the data sheet for the Opnext and the Mitsubishi diodes.
From my understanding I'm pretty sure I got it right. The Mitsubishi worked fine like this and after deciding that the anode and cathode were on the same pins (The same physical location I mean, not pin# as they are numbered differently) , I plugged the LaserBug into the Opnext.

Have a look here let me know if I goofed

.

What would happen if it was connected incorrectly? I thought there would be no action at all or it would have fried at power up not at 60-70% power output.

[p1t8ull]

The two diodes are the same pinout.
It sounds like you took enough ESD care handling the diode, and the D4Drive pro driver is an excellent protector.. as badger said, these are strong diodes so a very unfortunate death.

I would check the driver is doing what it should and there's no spikes when adjusting, ok not likely but easy enough to rule out.
Also check the insulation between the LD block and baseplate is not breaking down, with thermal changes as well.
And have a close look at the bug socket as it may be faulty or damaged in some way, was it forced onto another LD that still had solder on the pins for instance?

[kitatit]

The two diodes are the same pinout.
It sounds like you took enough ESD care handling the diode, and the D4Drive pro driver is an excellent protector.. as badger said, these are strong diodes so a very unfortunate death.

I would check the driver is doing what it should and there's no spikes when adjusting, ok not likely but easy enough to rule out.
Also check the insulation between the LD block and baseplate is not breaking down, with thermal changes as well.
And have a close look at the bug socket as it may be faulty or damaged in some way, was it forced onto another LD that still had solder on the pins for instance?

Hi Simon, thanks for your info I orderd a Rigol scope so hopfully in a week or so I should be able to check the driver. It's not out of the question for there to be an issue with the driver as I populated the components myself.

I'll have a look at the LaserBug socket. All the diodes I've used so far have unsoldered legs so it should be fine.

One thing I did forget to do is insulate the legs of the diode with heat shrink.
The Bug socket holds them fairly central but it is living dangerously. Better remember for my next try.

Cheers
Kit

[catalanjo]

One thing I did forget to do is insulate the legs of the diode with heat shrink.
The Bug socket holds them fairly central but it is living dangerously. Better remember for my next try.Cheers Kit

How does this work?

Doesn't the bug socket cover them completely ? Or are you referring to just the moment when you put on the back cover (Dave's diode block) to clamp in the diode before plugging the socket on the back?

Cheers

[RedlumX]

I don't know what the cause was, but generally speaking I'd avoid using sockets for laser diodes at all!
Reason being that the briefest interruption makes the driver go high, and when there is contact again, this high voltage, in the worst case buffered by a cap, is shot into the diode. Lasorbs should help (by preventing the voltage going up to too much in the first place) but how knows.

[catalanjo]

Surely this can only happen if the driver is powered up!

Cheers