Where did I go wrong with my 803T?

Hello everyone. It seems that I need a little help...

I just finished my first build. It was a PHR-803T HD diode with a rkcstr driver preset to 101ma. The diode was easy to harvest and I took all the proper precautions against ESD. It went into the Aixiz almost effortlessly.  Where I think I ran into trouble was trying to remove the PCB. (It was being stubborn and I think that I may have used too much heat.) After everything was put together I powered it up with a wallwart (9.22v) and... nothing happened.  :'(

So... a postmortem is in order.

How can I tell if I cooked the LD? How do I test the driver? It didn't show any voltage between "LD" and "GD" ?  Is that normal?  (I have only a very basic digital multimeter.)

Thank you for any insight that you can offer.

TW

what do you mean by "It didn't show any voltage between "LD" and "GD" ?"

Do you mean that you put the + and - probes onto the LD and GD pads while it was connected to a DMM?

and yes heat will kill your diode...Just look at my sig

After my LD failed to work I was curious if it was getting any power, so I  the put the + probe on the LD and the - probe on the GD. I didn't find any.
( Was that a bad idea? Could that damage the driver?)

I take it you have made sure that the mains adaptor is puting volts out?
Connecting the DVM to the output would not damage the driver. What you need to do now is to unsolder the LD, add a dummy load to the driver power it up and do some measuring.

Regards rog8811

T_Warne said:

After my LD failed to work I was curious if it was getting any power, so I  the put the + probe on the LD and the - probe on the GD. I didn't find any.
( Was that a bad idea? Could that damage the driver?)

Click to expand...

So you assembled it. It didn't work

Did you measure the power through the driver with the diode attached or did you remove it? Did you check to see if power was getting to the input side of the driver?

Peace,
dave

rog8811 ,
Is a "mains adapter" the wallwart power supply? It is putting out 9.2v. When I measure across the + - pads on the driver I get 9.2v. When I test at the GD LD pads I see no voltage. Unfortunately I didn't buy a test load because I bought a preset driver.

Dave,
I measured with the diode attached, but measure by testing at the GD LD pads on the driver. Am I not testing in the correct spot? What is the proper way to test a driver? Should I test with the LD removed?



Thank you guys for helping me. I appreciate it immensely.
TW

So as you know the supply is getting to the driver, Leave the LD in at the moment, put a resistor in the + wire to the driver (1ohm would be ideal anything of low value you have got otherwise) set your meter to mv and connect the probes each end of the resistor.
When you power it up, if you get a reading you are drawing current and we are a step forward.

Regards rog8811
Signing off for the night, I will catch up with this again tomorrow.

rog8811 , thanks for walking me through this process. I'll go buy the resistor, test again and let you know.  By the way... I just found your very helpful  post in "How to use a multimeter for measuring a current???".  Now that I know how, I'll test my LD and see if I fried it.
Thanks again and sleep well.
TW

Well, gentlemen, it's official. I managed to kill my very first phr803t LD [smiley=engel017.gif] ( probably even before I tried to power it up). I have to admit that this was a pretty disappointing outcome. I mean... I can follow directions like a mo'fo and I've used a soldering iron a time or two. This project was pretty straight forward... "put tab A into slot A" kind of stuff. It was definitely a beginner level exercise. Oh well. C'est la vie. Live and learn.

And what did I learn?
-Laser diodes are kinda' sensitive to heat.
-The search function is only good as what you "search for'... but the answer to almost any question can be found if you dig deep enough.


So... time for my second attempt.

Thanks again.
TW

I remember blowing a diode once   [smiley=engel017.gif]
















~runs

T_Warne said:

The diode was easy to harvest and I took all the proper precautions against ESD. It went into the Aixiz almost effortlessly.  Where I think I ran into trouble was trying to remove the PCB. (It was being stubborn and I think that I may have used too much heat.)

Click to expand...

This was your first mistake. If you want to use a soldering gun to get the PCB off, keep the diode in the heatsink it came with and solder it then before harvesting.

I recommend not using a soldering gun at all and instead use a sharp object to cut / snip / pry off the PCB material.

T_Warne said:

How can I tell if I cooked the LD? How do I test the driver? It didn't show any voltage between "LD" and "GD" ?  Is that normal?  

Click to expand...

Use a test load to test the driver.

and no it is not normal to not show any voltage.

-Kendall

T_Warne said:

Hello everyone. It seems that I need a little help...

I just finished my first build. It was a PHR-803T HD diode with a rkcstr driver preset to 101ma. The diode was easy to harvest and I took all the proper precautions against ESD. It went into the Aixiz almost effortlessly.  Where I think I ran into trouble was trying to remove the PCB. (It was being stubborn and I think that I may have used too much heat.) After everything was put together I powered it up with a wallwart (9.22v) and... nothing happened.  :'(

So... a postmortem is in order.

How can I tell if I cooked the LD? How do I test the driver? It didn't show any voltage between "LD" and "GD" ?  Is that normal?  (I have only a very basic digital multimeter.)

Thank you for any insight that you can offer.

TW

Click to expand...

ok...first off if there is no voltage between LD and GD then there is no power going to the diode.....
firstly, check and make sure you got your polarities right on the + and - side, if they are mixed up the driver won't work.

second, was your driver preassembled or did you assemble it yourself?
if you assembled it yourself can you take some close up pictures of the side that has the resistors on it.
you may have gotten something wrong as the instructions that are on ryan website are for the old design pcb and a couple of compnoents are turned around in the new design.

and of course, did you identify the + and - pins on the diode correctly?


also, and i know alot of people frown on this but it works great for me, once you harvest your diode, first put it in the aixiz module, then to remove the pcb board, i get a curves pick and slide it behind the board, then i get a big drop of solder onto my iron (big enough to cover all 3 pins), then stick drop of solder onto all three pins and then slide the pcb board right off.
i've never had it get hurt from heat as it take prob less than a second to get it off.

T_Warne said:

rog8811 ,
Is a "mains adapter" the wallwart power supply? It is putting out 9.2v. When I measure across the + - pads on the driver I get 9.2v. When I test at the GD LD pads I see no voltage. Unfortunately I didn't buy a test load because I bought a preset driver.

Dave,
I measured with the diode attached, but measure by testing at the GD LD pads on the driver. Am I not testing in the correct spot? What is the proper way to test a driver? Should I test with the LD removed?



Thank you guys for helping me. I appreciate it immensely.
TW

Click to expand...

WAAIITTT, are you attaching them right?

the diode should be connected to the LD GD side, and the power supply on the + - side.....

Kendal,
Sorry for the confusion...I actually did remove the PCB while the diode was still in it's original heatsink.
I like your idea of cutting the board off instead of using heat.  My wife has a really nice pair of cuticle scissors that I suspect will work perfectly. [smiley=happy.gif]
I don't have a test load. I bought a fixed driver and didn't think I would need one.

  Mohrenberg,
I think my trouble resulted from the fact my soldering station has a t i n y  .05" tip.  I can't really get a sizable glob of solder on it... barely enough to cover 2 pins at a time. I definitely spent too much time trying to heat too large an area.
The diode was attached correctly at the LD GD pads... observing proper polarity, of course.

TW