Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

How to Register on LPF | LPF Donations

81ma max output from rkstar micro-drive help

sportcoupe

sportcoupe

0
Joined
Aug 13, 2008
Messages
361
Points
0
I have a blu-ray laser pointer made by a member here. The output of the laser seems real low compared to a PHR blu-ray I have running 160ma. I check the ma on the blu-ray made by the member and it is only 61ma. That explains the low output, LOL.

I unscrew the business end (an easy host to work on I might say) and attempt to adjust the output on the rkstar micro-drive with my Fluke meter in series with the negative pin off the diode. I can only get a range of 55ma-83ma. This is supposed to be a full range rkstar driver so something is wrong.

I am using two brand new lithium 3.0 volt CR123's in my host. That's 6.26 volts at the rkstar driver. That should be enough correct? or do I NEED two 3.6 volt CR123's to properly operate the rkstar micro-drive? I read somewhere that blu-rays with the micro-drive need 7.0-7.2 volts.

I checked rkcstr's webpage and the micro-drive full range should have a series resister (R1) marked 2R7. The rkstar driver I have has the series resister (R2) marked 4R7. I do not have a parallel resister on the R2 position of the driver board which I read is only for the pot range of adjustment, not max output.
 
Last edited:





The diode needs something like 4.5-5v, the driver needs something like 2.5v... 7.5v is the minimum you should supply a rkcstr driver with for a bluray. With two 3.6v batteries you'll have full brightness only at a full charge... You'd be better off with 3x 3.0 or even 3x 3.6v batteries, but if your host won't accommodate more batteries, at least 2x 3.6v will be better than what you have.
 
sportcoupe said:
I have a blu-ray laser pointer made by a member here. The output of the laser seems real low compared to a PHR blu-ray I have running 160ma. I check the ma on the blu-ray made by the member and it is only 61ma. That explains the low output, LOL.

I unscrew the business end (an easy host to work on I might say) and attempt to adjust the output on the rkstar micro-drive with my Fluke meter in series with the negative pin off the diode. I can only get a range of 55ma-83ma. This is supposed to be a full range rkstar driver so something is wrong.

I am using two brand new lithium 3.0 volt CR123's in my host. That's 6.26 volts at the rkstar driver. That should be enough correct? or do I NEED two 3.6 volt CR123's to properly operate the rkstar micro-drive? I read somewhere that blu-rays with the micro-drive need 7.0-7.2 volts.

I checked drlava's webpage and the micro-drive full range should have a series resister (R1) marked 2R7. The rkstar driver I have has the series resister (R1) marked 4R7. I do not have a parallel resister on the R2 position of the driver board which I read is only for the pot range of adjustment, not max output.
Click to expand...

correct me if i'm wrong, but i'm pretty sure the full range uses a 10 ohm pot, a 20.5ohm (20r5) resistor on R1 and a 2.7ohm (2r7) resistor on r2.....
there is no resistor on R2? i didn't even know the driver could work without something there...
 
Last edited:
pseudolobster said:
The diode needs something like 4.5-5v, the driver needs something like 2.5v... 7.5v is the minimum you should supply a rkcstr driver with for a bluray. With two 3.6v batteries you'll have full brightness only at a full charge... You'd be better off with 3x 3.0 or even 3x 3.6v batteries, but if your host won't accommodate more batteries, at least 2x 3.6v will be better than what you have.
Click to expand...


This is my host. Looks like two 3.6V CR123's are my only option.
http://www.dealextreme.com/details.dx/sku.21036
 
Actually come to think of it that's pretty low, even if it had dropped out of regulation due to lack of voltage... I'm thinking you should measure the resistance across the pot at it's max settings in either direction... I'm guessing the range should be somewhere between 2ohms and say, 30 ohms, or thereabouts.
 
Mohrenberg said:
correct me if i'm wrong, but i'm pretty sure the full range uses a 10 ohm pot, a 20.5ohm (20r5) resistor on R1 and a 2.7ohm (2r7) resistor on r2.....
there is no resistor on R2? i didn't even know the driver could work without something there...
Click to expand...



Well, let me correct. I was TOLD that the rkcstr micro-drive was the full range version BUT the R2 series resister is marked 4R7, not 2R7 like rkstar webpage says it should be. There is no R1 parallel resister which is OK according to the spec sheet on the driver.
http://rkcstr.googlepages.com/MDADJv2instructions.pdf
 
Last edited:
oh wait... what am I talking about?

disregard my post about voltage, I thought you were talking about rkcstr's driver, not drlava's... geez, I really need some sleep.

DO NOT give the lavadrive more power, instead change the resistors or pots or something. Sorry!
 
pseudolobster said:
Actually come to think of it that's pretty low, even if it had dropped out of regulation due to lack of voltage... I'm thinking you should measure the resistance across the pot at it's max settings in either direction... I'm guessing the range should be somewhere between 2ohms and say, 30 ohms, or thereabouts.
Click to expand...



I just measured across the pot, I got 1.2 ohm at max turn (clockwise) and 10.2 ohm at min turn (counterclockwise).
 
Last edited:
I did a little more troubleshooting. I suspected the low battery voltage so I un-soldered the host from the rkstar driver and connected a bench power supply set at 8 volts. Guess what? I could now get full range, I stopped at 200ma and backed it back down. The rkstar driver NEEDS a minimum of 7.2-7.5 volts with a blu ray diode. The member I bought from should have known this as he sells here ALL THE TIME. Now, the only way I can get good output (with the current host/driver setup is with two 3.6 volt CR123's and I will only see max output when the batteries are at full charge.

Shall I send it back and ask for a refund?
 
first off, you can use up to 12 volts with the rkcstr from what i read most members use 9 volts, although try not using the square 9 volt batts cuz they have low mah rating. next what host are you using. that will dictate the batteries. hope this helps.

michael
 
that isnt enough voltage for the rkcstr driver. you need the lava drive. the rksctr and blu-ray need a minimum of like 7.5 and that is min. most people use 9-12v.
 
For the drlava FlexDrive, the voltage would be too high in this host, unless you use only non-rechargeable CR123A batteries and add a series diode before the driver to drop the voltage a bit, or use just one battery (and possibly a spacer). Max input voltage is 5.8V IIRC.
 
Just out of curiosity, who sold you this laser (just to protect other potential buyers from encountering the same troubles) ?
 
@drebert. he said in the begining of the post that he is using 1- 3volt battery. I don't think many people caught that. and he is using the rkcstr driver. isn't 3-3.6 good for the lava drive. my opinion is to switch from the rkcstr to the lava.
 
You must log in or register to reply here.


Back
Top