Why did my 642nm diode die?

[allthatwhichis]

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.

Gues this is a good time for a poll; has anyone had a diode die using a Laserbug?

[catalanjo]

Gues this is a good time for a poll; has anyone had a diode die using a Laserbug?

I'll second that !

Anyone know how to set it up ?

Cheers

[dnar]

As the diode died while adjusting current, my money is on this as the cause.

I always fit a dummy load (diodes and resistor) to make a current adjustment, unless it's the 445 tough as nails diode.

[mixedgas]

"Die using a laserbug"

Patently unfair question from the Engineering point of view, properly installed and mounted so shock does not pull it off the diode, the only thing on that could go wrong is the socket to laser lead connection being loose.

Steve

[kitatit]

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

The legs of non harvested diodes are a bit longer so they aren't completely covered. If the Laserbug gets knocked there is a small chance the pins could bend and short on Daves diode mount.

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.

Yes this does seem a common concern. I think I might hard wire them when I install them in my projector.



Updating my progress-

I bought a scope and checked the power supply and driver and they are clean and working nicely.

My second diode is now working well! YEEAH!!
I didn't do much differently. I double checked my grounding, shorted the diode straight out of the bag, fitted a Lasorb to the the laserbug, closed on eye and hit the switch... presto! it works.

One thing I did notice is that the first diode had noticible wings on the beam while the second one doesn't...? weird.

Thanks for your help guys, I'm feeling a bit more confident now.

Cheers
Kit

[catalanjo]

"Die using a laserbug"
Patently unfair question from the Engineering point of view, properly installed and mounted so shock does not pull it off the diode, the only thing on that could go wrong is the socket to laser lead connection being loose.
Steve

Exactly ! ..... That would be the purpose of a poll... to find out if this happens often, never or once in a BLUE (or RED) moon !

Cheers

[dnar]

The legs of non harvested diodes are a bit longer so they aren't completely covered. If the Laserbug gets knocked there is a small chance the pins could bend and short on Daves diode mount.



Yes this does seem a common concern. I think I might hard wire them when I install them in my projector.



Updating my progress-

I bought a scope and checked the power supply and driver and they are clean and working nicely.

My second diode is now working well! YEEAH!!
I didn't do much differently. I double checked my grounding, shorted the diode straight out of the bag, fitted a Lasorb to the the laserbug, closed on eye and hit the switch... presto! it works.

One thing I did notice is that the first diode had noticible wings on the beam while the second one doesn't...? weird.

Thanks for your help guys, I'm feeling a bit more confident now.

Cheers
Kit

Cool. You went with the Rigol DS1102E? Give me a bell if you have trouble installing or getting the PC software to function. There is a missing piece to the puzzle that took me ages to sort out! Otherwise, a good DSO for low $$$, much lower than Tektronics...

[kitatit]

Cool. You went with the Rigol DS1102E? Give me a bell if you have trouble installing or getting the PC software to function. There is a missing piece to the puzzle that took me ages to sort out! Otherwise, a good DSO for low $$$, much lower than Tektronics...

Yeah, I went for the ds1102e. It was only $506AUD delivered! so didn't bother going the firmware hack route with a 1052e. I got it from youroscilloscope.com. Good service and arrived in one week.

Thanks for the help, I'll definitely need it. I haven't tried the software yet.

I know the basics of how to use a scope but I'm definitely no power user

[White-Light]

The legs of non harvested diodes are a bit longer so they aren't completely covered. If the Laserbug gets knocked there is a small chance the pins could bend and short on Daves diode mount.

Why don't you just snip them shorter with wire cutters so they match the harvested length?

Seems to me would remove the problem.

[catalanjo]

The legs of non harvested diodes are a bit longer so they aren't completely covered. If the Laserbug gets knocked there is a small chance the pins could bend and short on Daves diode mount. Kit

Where are people "harvesting" these 642nm diodes from?

Did you drill Dave's back plate out to 5.1mm so that the bug socket could enter right up to the diode ??

The opnext spec sheet doesn't show the leads as being very long.

The only tricky bit I can see is placing the (drilled out) back cover over the diode pins where heat shrink might well come in very handy. How did you deal with that bit of the mounting procedure?

Also what collimating optics are you using?
Are you knife edging?
Any ideas about telescope optics?

Cheers