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FrozenGate by Avery

FS: MXDL Host & Heatsink Combo! (4171 or 3405)

Re: FS: MXDL Host & Heatsink Combo! (4171 or 3405)

daguin said:
I built a 4171 today to evaluate the your competition's Big Chunk. I discovered something that should be incorporated into this and several other threads. The "new" 4171 has its "pill" filled with white silicone. The positive lead comes out through the middle of that silicone. However, buried inside that silicone is a resistor in the positive lead. You have to dig/cut the silicone out of the middle, cut the resistor off, and solder a new positive lead onto the stub.

The disc at the bottom (the battery contact) is "glued" to this silicone. It is not a difficult step, but with the resistor in place the current to the driver is severely restricted. The build is a 6X. I set the flexdrive at 200mA with my bench PSU. As I always do, I checked the driver after installing it onto the host. This lets me check the current with actual battery power before attaching the diode. The flexdrive was only giving me 78mA with the battery as power! Some investigation led me to the resistor in the silicone.

Peace,
dave
Click to expand...




Good on you Dave for making that known!

I'll make a note of it at the beginning of this thread and where I talk about the differences between the 'new style' 4171...
Jay
 





Re: FS: MXDL Host & Heatsink Combo! (4171 or 3405)

TJ, I will make it to the Post Office today before they close. I will have your 4171 host/heatsink combo with 'Hot option' and other items shipped Priority as per our agreement...

Your driver is set to 422mA's. The FlexDrive is sensitive at this area. I wanted to get 420 on the nose, but had to settle for 422mA's.

Let me know how your build goes!
Jay
 
Re: FS: MXDL Host & Heatsink Combo! (4171 or 3405)

jayrob said:
I wanted to get 420 on the nose, but had to settle for 422mA's.
Click to expand...
That's a 0.5% difference. Just how precise are your measuring resistor and DMM (in x% +/- y digits)?
 
Re: FS: MXDL Host & Heatsink Combo! (4171 or 3405)

Not sure if that is a real question or not. :)

Because I don't understand...

But just to clarify, I use a rkcstr test load. (one for red and one for blu-ray - they are great by the way) The FlexDrives in the highest range, are very touchy in the 420mA neighborhood.

It seemed to jump from 416mA's to 422, or even 426mA's. I noticed this same behavior with some of the other version drivers. But 422mA's is close enough to the 420mA's that was agreed upon for his kit...
Jay
 
Re: FS: MXDL Host & Heatsink Combo! (4171 or 3405)

Yes and no  :)

The voltage drop resistor in the rkcstr test load is 1.0 Ohm with a precision of 5% according to this source. The DMM introduces its own error (2nd part of my question). That means you CAN'T measure the current more precise than plus or minus 20mA in that range - possibly less. The DMM may show more digits, but it would be "empty precision".

EDIT: Assuming the DMM has a precision of 0.2%+2 digits, and you're measuring in the 2V range, then the error from the DMM would be plus or minus 6mV [mA] which might explain the "jumping". Note that the stated error for a DMM refers to the range you've selected, not the value displayed. The absolute error in this case would still be caused by the resistor.
 
Re: FS: MXDL Host & Heatsink Combo! (4171 or 3405)

dr-ebert said:
Yes and no  :)

The voltage drop resistor in the rkcstr test load is 1.0 Ohm with a precision of 5% according to this source. The DMM introduces its own error (2nd part of my question). That means you CAN'T measure the current more precise than plus or minus 20mA in that range - possibly less. The DMM may show more digits, but it would be "empty precision".

EDIT: Assuming the DMM has a precision of 0.2%+2 digits, and you're measuring in the 2V range, then the error from the DMM would be plus or minus 6mV [mA] which might explain the "jumping". Note that the stated error for a DMM refers to the range you've selected, not the value displayed. The absolute error in this case would still be caused by the resistor.
Click to expand...

Hey Doc...
have you seen the latest FlexDrive.... :-?

They are tiny.... and for that reason... they have a teeny tiny single turn Potentiometer...
and the 420-422mA setting is near the extreme end of adjustment...

That is the main reason that it is difficult to get an exact adjustment...
Lab quality adjustments with multiturn pots.... just wouldn't fit on the PCB... IMO

I do understand the +/- precision errors.... but once the 1 ohm is chosen with it's inherent
tolerance error... that error does not become variable.... it is only variable between different
1 ohm parts...
That tolerance error is not the main cause of jayrob's slight adjustment problems....
it is the tiny PCB mounted potentiometer...IMHO..8-)

Jerry
 
Re: FS: MXDL Host & Heatsink Combo! (4171 or 3405)

IF the pot is logarithmic, it would be more sensitive at the high end of the range, yes. If it's linear, it wouldn't matter. However, it appears that Jayrob always gets the same display values; that sounds more like an A/D-conversion "staircase" effect.

In any case, the absolute precision would still be limited by the resistor.
 
Re: FS: MXDL Host & Heatsink Combo! (4171 or 3405)

dr-ebert said:
IF the pot is logarithmic, it would be more sensitive at the high end of the range, yes. If it's linear, it wouldn't matter. However, it appears that Jayrob always gets the same display values; that sounds more like an A/D-conversion "staircase" effect.

In any case, the absolute precision would still be limited by the resistor.
Click to expand...

I agree with you 100%... the absolute precision is still limited by the resistor... 8-)

That is not where jayrob's problem in adjusting exactly 420mA on his meter came from...
It has to do with the physical size of the human hand and its ability to make minute adjustments
to the pot and the physical size of the PCB mounted Pot...
I know... I've tried this.... 8-)

I'm sure that you would agree... that it is very difficult to manually adjust a 1 ohm
difference on a 1K pot if the physical resistive path was only 0.100" or less in length
even if it was linear... :-?    (not sure of the pot's actual value... could be 5K)

BTW... here is a photo of the driver in question....

http://www.laserpointerforums.com/forums/YaBB.pl?num=1209418066


Jerry
 
Re: FS: MXDL Host & Heatsink Combo! (4171 or 3405)

There is a thread somewhere where Dr. Lava mentioned why there is this slight 'jump' at certain currents...

I just don't know where it was.

Anyway, it is taken for granted that there are other resistance factors such as the meter itself...

I personally don't see a problem with getting a reading with-in two mA's of what the goal was. The difference is power will only be 1 or 2mW's...
Jay
 
Re: FS: MXDL Host & Heatsink Combo! (4171 or 3405)

John H., your 3405 Host/Heatsink combo with 'Hot option' will be in today's mail!

It is set at 276mA's per your request. (close enough to 275)

Your other items will be in the package as well. Let me know when you get them!
Jay
 
Re: FS: MXDL Host & Heatsink Combo! (4171 or 3405)

jayrob said:
John H., your 3405 Host/Heatsink combo with 'Hot option' will be in today's mail!

It is set at 276mA's per your request. (close enough to 275)

Your other items will be in the package as well. Let me know when you get them!
Jay
Click to expand...


275mA? Is that for a 6x? :o
 
Re: FS: MXDL Host & Heatsink Combo! (4171 or 3405)

He is building a red laser using the 1239JL-54 Sony/Senkat diode...






For people to see, I have a picture of what my 'HOT option' looks like on the (new style) 4171 host:

Important: The (new style) 4171 host has a resistor buried in silicone. (inside the pill) This needs to be removed. (with the 'Hot option' this is removed, and a silicon diode is mounted inside the pill to drop voltage to the FlexDrive) Use only 3.0 volt Lithium batteries for this set up. Not 3.6 volt...

4171 Hot Option.jpg

Jay
 
Re: FS: MXDL Host & Heatsink Combo! (4171 or 3405)

Zithras, your silver VicLight side button host/heatsink combo and other items shipped today! (Thursday)

That's the last of my VicLitht side button hosts...

Hope you build goes well!
Jay
 
Re: FS: MXDL Host & Heatsink Combo! (4171 or 3405)

Felipe, just to let you know that your 4171 Host/Heatsink combo (version 2) and other items will be in Monday's mail...

Please let me know when you get the package! :)
Jay
 
Re: FS: MXDL Host & Heatsink Combo! (4171 or 3405)

nastynick, your 4171 Host/Heatsink combo (Meredith version 2) and other item shipped today...
Thanks!
Jay
 
Re: FS: MXDL Host & Heatsink Combo! (4171 or 3405)

Joris, just to let you know that your 4171 Host/Heatsink combo with lead wires ready (and other item) will ship tomorrow! (Monday)

Let me know how your builds go!
Jay
 
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