rkcstr driver + SLD1239JL-54 Problem

[brownj]

I'm using a Sony SLD1239JL-54 16x DVD Burner, a rkcstr adjustable driver, and an Aixiz module. This is my second attempt at creating a laser. My first time, I hooked one of these diodes directly to two AA's. It ran amazingly for about five minutes, before it burnt out in a puff of acrid smoke. :banghead: For this reason, I have a dead diode. I hear these can be used as test loads? So far, I've hooked the driver up to 5 AA's (rechargeable, so they're only at 7.2 volts, total), adjusted the output to around 180 ma (I didn't use a test load), and attached the new diode. I completed the circuit and...NOTHING HAPPENED. I checked the output again by connecting my multimeter to the diode's pins and got the same reading as before I attached the diode. The driver started heating up when I attached the multimeter, but stayed cool when only the new diode was attached. It looked like the diode was blown, so I decided to test it. I hooked it up to two AA's for an instant. :banned: It shone bright red, so I know it's fine. (It didn't blow) I know I have all of the polarities correct, but I have the feeling I missed something vital. Can you guys help me out? What should I do?

 

[chipdouglas]

if you are sure the LD is still good then check your solder joints.

5 aa's are min 7.5 v. and charging will make the more. which is good.

next you say you set the driver at 180 mv. but no test load was used. then how do you know?

next you say you tested the good LD by hooking it up to 2 aa batts w/out driver. it worked but now it doesnt. even though it worked for a second, it doesn't mean it will still work. that is not a valid means for testing a good diode.

one thing that isn't clear. did you use your multi meter to directly check your LD. there is debate that the elctricity in a dmm can damage a working LD.

build tips for future.
always check the driver current (even if mfg says it is pre set)
always short the capacitor (touch the neg and pos side where LD goes)
make good solder connections every where (use a 25 Iron.)
insert LD in housing.

 

[LarryDFW]

brownj;

I assume this is the 2nd Red diode.

Red's are pretty durable.

I would guess the driver is not delivering enough current.

Try setting it at a slightly higher current level to see if it lights.

LarryDFW

 

[brownj]

Thanks for the feedback, guys! I tested the driver's setting by hooking my multimeter directly to the output. I know this isn't as effective as using a test load, but it should have been close enough. I'll check to see if the diode lights when the driver is cranked. I'll post again with the results.

 

[billg519]

As you may have noticed, a lot of us here disapprove of the idea of hooking an LD up to batteries directly. If you hook it to 2 x 1.2V NIMH cells, you may be OK. Hook it to 2 x energizer 1.5V alkaline and it may blow instantly. The 2.4V is probably not enough to make a cold diode draw its' rated current. On the other hand, 3V may be close enough to the diode's operating voltage that it would draw excessive current and blow. If you absolutely must test with batteries, at least use a series resistor of a few ohms to limit the current, also stick to 2 x NIMH batteries for this "test".

You really need to make up a test load. It only takes 4 x 1N400X diodes and a 1 Ω resistor. Current is measured by putting DMM set to DC mV across the 1 Ω resistor, 1 mV = 1mA. A DMM across the driver output may not let you set the driver accurately, as the load presented to the driiver by the DMM will probably not match the load characteristics of an LD.

Hope this helps.

Bill.

 

[rog8811]

Using your multimeter directly on the output tells you nothing, you need to load the circuit to the same level as an LD. You could try the known dead LD as the load with the miltimeter in series measuring ma.....or you could make a test load for a few cents.... I know which I would do Look at the driver page on my website (link below) the same test load works for any drive circuit.

Regards rog8811