Help me identify these diodes.

I've just taken apart a few DVD burners.

First one is a LG GH22NP20. It's a 22x DVD burner and the Sony is 18x I think. LG's red diode is capable up to 450mA if I've read correctly and the Sony's is capable up to 290mA. Both diodes are 5.6mm and probably open can. Again, I'm a noob, everything is possible.





Now I know that one diode is IR and the other is red.
I can't take get the diodes out of the heatsinks (and since I don't have a module I don't want to really)
The round diode seems to be a 5.6mm and I honestly think the flat one is IR (I certainly hope so )

Now the Sony Optiarc AD-7170A.





And here are all the tiny bits. Care to explain what they are?

I'm thinking the round diode is the red and
the flat one the IR. Sometimes you can tell
by looking at the dicro in front of the diode.
Red diodes will have a blue dicro, and IR
ones can have a pale blue or silvery dicro.
It also wouldn't hurt to try powering them up
on low current. Just make sure they're
pointed away from you when doing it.

No diodes have blue coatings.
One doesn't even have a lens in front of it, it's the open can diode of the Sony.
What currents are safe for IR diodes? I won't need them probably but still.
And will I even see a glimmer of red light?

You will see a faint red from the IR diode.
Most of them can't handle much current.
Maybe 200mA
It also helps if you have an LPM. Most IR
diodes will die above 160mW. The red ones
are better, safer, and more interesting in
almost all cases. Most of them are case
negative. The all diodes thread is a good
source of info and pinouts.

If there is an R stamped into the back
(ROHM) then it won't do any more than
100mW.

Also, many of the round IR diodes will have a
can without a window. A real open can is
completely open and has no can at all.

The flat ones can be either red or IR. Some
of them are dual and have both.

Thank you. I measured all the round ones and they are 5.6mm.
I'll have a look.
I'll try to run one diode tomorrow at 125mA and we'll see what happens.

No diodes have blue coatings.

HE was NOT talking about the diodes (or its window) the square piece of glass directly in front of the diodes is a dichro mirror coated to allow one color or more pass and reflect other(s)
so its a window not a lens that may be in front (closed can IE)
and the dichro is not attached to any diode.


One doesn't even have a lens in front of it, it's the open can diode of the Sony.
What currents are safe for IR diodes? I won't need them probably but still.
And will I even see a glimmer of red light?






... some would advise to NOT put any power until pressed in a proper module and that into a proper heatsink ==

Or the dim red will be the red diode in 'LED Mode'

also I hear repeated quick power on and off is also NOT too good a thing even if in a HS

better have the correct pin-out too

back with a pic for you

3rd pic wont load

also if you are ordering these from aixiz.com you may also want one or more of the new single glass lenses A-2- personally checked out for 445 and 5% better than the 'G' for blue(so good for 405 too-may ALSO be good for reds too

only 8$ usd and if you order (not from ebay or amazon) you might get free shipping because you are laser forum and you found these with my help (thanks)

here are a few of the things at AixiZ that makes doing dsome things like testing much easier and safer

long wired plug for diodes-- made originallly for laser printers... the spendy ones that do actually get worked on-


using these i would not fear attaching to a adjustable power supply using the pin-out and this wired plug then you could walk the voltage up slowly and carefully & if you have it on a LPM you can see when you are going too far-
This needs to be done for a long test with a module and heatsink BUT to quickly test for color etc IF the diode is still in the original heatsink you would be safe
just keep the time ddown to a few seconds- take care removing the heat sink some can be a HUGE PITA- use two sets of pliers or vice gribs and gently twist in tiny movements- not much to grab ahold of - somer are easy some NOT.

this item i have not seen yet in person

3 pin socket mount for laser diodes, AixiZ

Thank you a lot! I meant the dichros in front of the diode (I don't know what dichros are, I'll look it up...) don't have blue coatings. And I don't have a LPM, it's a few hundred dollars away from me... I don't even have a vice, a multimeter or a third hand for holding stuff when soldering. So yeah I'm screwed.

hakzaw1 said:

... some would advise to NOT put any power until pressed in a proper module and that into a proper heatsink ==

Click to expand...

I have seen this as well and am not sure
where it originates from. After all, the
diodes were working just fine in those
heatsinks the whole time they were in the
drive. I have done it many times, and never
blown a diode this way. I have even run
diodes at 60-80mA (just above threshhold)
with no heatsink at all for short pulses,
paying careful attention to temperature. It's
not like I really cared if I blew them, since I
got them for free anyway. Diodes are far
more tolerant of a little heat than
overcurrent and ESD. Many diodes have died
by my hand those ways.

To the OP, I suggest you keep stripping down
old equipment until you find a 22 or 33 ohm
carbon resistor of a decent size (not
wirewound). They are usually tan or blue and
have a smooth surface. One of those in
series with the diode will be just about right
at 5V. Then find an old 5V phone charger
and you have a diode tester. Always start
with the power supply unplugged and short it
out before attaching a diode.

I don't think lower currents will damage the diodes, they are all still in their little heatsinks.

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