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Help with PHR / rkcst driver build

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alanbrito

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I have a problem.

I purchased the PH3803T sleds to get the 405 nm diodes from them. I also got the rckstr driver and a test load, all from Modwerx.

Now I do not know what the problem is. I connect the driver to a voltage source to the +/- terminals. The LD+/LD- terminals go to the diode, but instead of the diode, I have the dummy load connected. In the dummy load, I am supposed to measure the voltage across a resistor, where 1mV should be 1 mA; and then change the pot in the driver to adjust for the current that will be given to the diode.

Well, the issue is that I am getting between 1.75 and 2.02 mV through the reistor, that is all the range I get from twisting the screw in the pot in the driver.

Can I get some help? I don't know what's wrong; I thought I'd be getting something like 100 mA/mV. Is the voltage I am using correct? Could it be a bad driver? HEEELP!

PS: I searched for something like this but found nothing... I think I am doing everything right.
 





Are you sure your multimeter is set to the correct range? IT should be on the 1v or 2v setting.
What power source are you using? It'll need to be at least 7v, preferably as much as 12v.
Also, what setting is the dummy load set to? There's a jumped labeled red or blue. You'll want to solder a bridge over the blue jumper.
 
Its a digital multimeter, set to mV range, but I get the same under the V range, so that's not it. I do have the rkcstr dummy load... WHat is this about soldering a bridge? There is a red/blu label... I haven't soldered anything there. Please confirm if that's what I need to do... And if so, I'm an idiot.
 
I am using a voltage/current source from our lab, it is a constant voltage/current power supply, and I can change the voltage; I was testing it with 5V, but even at 12 V I am getting only 6 mV through the test load resistor...
 
I can't find my test load right now, but I think if you solder neither of the jumpers, the current doesn't flow through the diodes, making it so the test load is basically just a resistor. Yes, you'll want to solder a bridge over the two dots labeled "blue".
 
I'll wait to hear a confirmation on this; if you're right, you have just prevented me from shooting myself. I need to get this working for an experiment.
 
If the solder bridges are set up correctly (read the test-load manual to confirm this?), then it might be that the load is wired in reverse polarity, that might cause the issue you're describing.
 
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