Harvesting DVD Burner Diodes...

I've gotten pretty good at harvesting diodes from DVD burners....

But there is still one facet of the harvesting process that stops me dead in my tracks.

How to easily unsolder the diode from the Mylar trace material in the burner!

I also try to use 20X burners and they all seem to have open can diodes!

That adds a whole new level of complexity to this process!


Anyway, today while trying to build a new and improved Dorcy Mini laser...I managed to KILL my last two diodes!

BOTH of them while in the process of desoldering them from the Mylar!

One I litterally SHOT across the desk while pulling on the mylar and melting the solder!!!!

The second one, I enlisted the help of my Lovely bride to hold the diode in a pair of needlenosed pliers by the rim....

I made the mistake of saying.."Now Don't hold it too loose, otherwise I'll pull the diode out of the pliers"...

Next sound you heard was CRUNCH......"Ummmm....Well...that was tight"....

80 bucks worth of diodes gone in 10 miniutes!!!!

I need a good proceedure for desoldering harvested diodes that has solutions to these issues
1 How to hold the diode
2 How to heat enough desolder but still keep the diode cool

I was thinking about the 16X GB diodes (don't have to desolder them), but I find the open can 20X diodes are better burners.

Thanks for the help!!

Larry

Larry,
I use helping hands and very quickly heat the pins at the same time and remove the mylar with a needlenose. I have yet to lose a diode using this method. The alligator clip on the helping hands helps to keep the diode cool. Helping hands are very valuable for the type of "work" we do.

Mine are like these but search around on ebay:

http://cgi.ebay.com/HOBBY-TOOL-HELP...oryZ2594QQssPageNameZWDVWQQrdZ1QQcmdZViewItem


I fully agree with you about the open can diodes being better burners. But for the price the GB diodes can't be beat and are perfect especially for those new to this hobby. I have some more on the way, but I also have a 20X DVD burner on the way for harvesting... ;D

Thanks to VaThink, I found the easiest DVD burner to remove an open can from is an 18X Pioneer 112D. From now on I am going to order those as the Lite On's are a pain to remove...at least for me. From everything I have read it seems all open can diodes are the same...I just wish we could find a spec sheet for them.

BTW, using my TEC and open can with a Meredith module, I was able to punch a hole clean through a floppy disk in less than 10 seconds. This does require at least 350ma's of current going to the diode.

I would say get something to grip around the diode and get a solder sucker that will pull up the molten solder. and possibly a little copper wick to get the residual solder off if you can't get it all with the solder sucker

And I just looked and radio shack has both items...

The helping hands and the sucker. (I had a nice spring activated one...but I guess someone liked it more than I did and walked with it).

I was trying to use the solder wick but it heats the diode too much.

I'll be stopping byRadio CRAP tomorrow...

Though I give fair warning...one of those Radio geeks asks me "What do you need that for?" just ONE MORE TIME...and..I'll be posting my next reply from JAIL!

May even go get ANOTHER DVD burner to harvest.....

Larry

Rhith,

The problem using either of those methods is you need to apply heat to the diode longer than using the quick "pop off" method I use. Any residual solder left over after removing the mylar doesn't need to be removed. I hate solder suckers.. ;D But I do like solder wick.

If I were to choose between the two I would use a solder sucker for this application. But still, simply heating up the pins at the same time and quickly removing the mylar with a needle nose is the quickest...IMO.

Piece of cake!
Cut the foil off short of the diode.
Put a small blue flame at all the leads for 2-3 sec and just yank the whole tape foil off those pesky LASER leads at once.

If your soldering tip is fat enough to touch all the leads at once, then you don't need the flame.

NO MORE THAN 2-3 seconds!!!!!! HEAT KILLS LASERS AND STATIC TOO

Sometimes I just liquify solder joints and indirectly bang the joint lightly againts something and solder flings off. Watch molten blobs fly on your skin! OUCH :'(

Technique is everything!

Pitty you lost those harvestees

CHEERS, BEAM OUT, [smiley=beer.gif]

Gazoo - I find that using teh bulb-type d-soldering iron with a tiny amount of flux to be the best bet out there...I have yet to have ever destroyed a component by desoldering - you slathe on the flux (or rosin- whatever it is labeled as) Squish the bulb down, put the hollow tip around the pin to be desoldered - touch it to the solder and flux combo, release the bulb, and remove the iron from the pin. The act of "de-squishing" the bulb has two effects on the solder and pin... number one, it sucks the solder away from teh spot with great force, leaving you with a nice, slean, pre-tinned pin, and it also COOLS down both the solder as it is traveling away, and the pin at the same time - removing heat swiftly from whatever component you are desoldering ! I love those little red-bulbed de-soldering irons....I DID have a custom made one that I created out of a 12v emergency tire inflater at one time - the powered suction was fantastic, and worked like a champ up until my move when the movers kinda smashed the "device" and it was KINDA hard to put a value on someting that cost $10 to make hehehehe

SenKat, et al,
I got a red bulb sucker from Radshak for $30 and you can replace the tip when it dissolves.
40 Watter.
But I still just bang the solder off when I can! Air Blowgun works too
Trick is to be quick, before solder hards.
I'm a old timer with the soldering thing.

You're right about reflowing with flux, causes sometimes the solder will not liquify.

If the leads are bent over BUMMER, then I use a heated needle nose pliers
so the stuborn lead can be straghtend and pulled out.

Don't you hate it when leads to desolder are twisted?

Bottom line is sucking solder off and then breaking the connection takes longer.

I just melt and bang the solder off. Then I might have to do some SUCKING but that SUCKS!

I take junk circuitboards and torch them outside them slap em down on the concrete and get big yields of components at once. then just sweep up the solder globs and finish up with the old iron and a pair of dikes and needlenose.

Cheers [smiley=beer.gif]

I hate solderwick it draws soo much heat from the iron. Last resort!

It's a solder fling thing with me.

again here comes my .02¢ I take a needle and apply pressure to the underside of the mylar. Then using my other hand, I bring the very hot soldering iron tip onto the solder on the other side of the mylar of the needle. the pressure on the needle pushes the mylar off and the solder goes with it! I then move to the remaining pins one at a time. Usually I only need enough time to melt the solder and that is it! I've tried the bang it method and the wick and teh bulb method. all of which require more time of heat on the pins than having the constant pressure of the needle push the mylar away from the pin as soon as it's hot enough to melt. Which is usually instantly with my iron.

Hope that helps.

Ok....I'm a complete idiot.....

All I need to do is re-arrange my harvesting steps to VASTLY improve the situation.....

Every diode I've harvested is mounted in a small housing that was "Glued" into place in the DVD read head...

I would always make getting the diode OUT of that module my first priority.

THen I would have a Bare Open can diode with the mylar still soldered to the pins!

Why not use that small housing to our advantage before we extract the diode from it!!!!??????

1) It gives you something to GRIP without hurting the actual diode. (It's fragile end is completely covered and protected by that housing)
2) It adds mass to the diode, and acts as a heatsink to take away heat during the de-solderin/soldering process. (less chance of Cooking the diode).

Heck you could place the diode while in that little housing in a pair of pliers, vicegrips or even a big VISE and not hurt the diode!!!!!....
Desolder the Mylar and Solder some nice new Long wire leads all while the housing, that your going eventually throw awayway, is doing some good!!!

THEN remove the diode and toss the little housing away!!!!

Hold the diode ONLY by the 2 wire leads you soldered, and go directly into a prepared AixiZ module.

Much less chance of any damage to those fragile open can diodes!!!

Larry

I am not sure which module you have, but with my modules the wire leads would be in the way when pressing the diode in. I always press the diode into the module first, then solder the leads. Other than that.... good thinking.

Gazoo said:

I am not sure which module you have, but with my modules the wire leads would be in the way when pressing the diode in. I always press the diode into the module first, then solder the leads. Other than that.... good thinking.

Click to expand...

Not really....

I assume that you are using the back of a module to press the diode home...
It has a hole on the back just large enough to prevent pressing on the pins...

The wires can come right out that hole as well....

I just use a spare housing that I use only for pressing in diodes.
It was the scrap piece from doing a Dorcy Jr Laser Mod
In that Mod you need to cut an AxiZ module to shorten it.
The end left with the small hole is scrap....and what I now use for pressing in Diodes.

Just dremmel a NOTCH in the side of it deep enough to be able to route the 2 wires.

THat will get them out of the way and keep them from being cut when pressing the diode in.


EASY.....

I like the idea of having the leads attached when removing the diode from that last piece of the DVD burner...
It gives you retention of the diode...something to hang onto and aid in extraction

And If done carefully...your fingers never even have to TOUCH the diode!!!

Larry

I've come across a problem harvesting open can diodes... How do I get them out of the aluminium holder they're in? With the closed ones, I could be rough and cut away the aluminium holder with side-cutters, but with these open can ones I seem to make a mess of them.

well everyone uses side cutters on the open cans too!

OK, I guess I just need to be more gentle

The way I did it with the 112D was to apply pressure to the part of the heatsink the die is mounted on with a needlenose and press it out, but I got lucky. Of course whenever I get a open can that actually works after I have harvested it, I consider it luck. ;D

VaThink recommended using a pliers to press it out of the heatsink. This might work if pressure is evenly applied to all of the top part of the diode. The problem is with the brass, it is soft and can easily bend at the outer edges of the can. Maybe the best solution would be to press it out with a drill press...unfortunately I don't have one.