X-boost not changing output much with turning pot

Hi All,

I am not sure what's going on here, this was my first time doing this and I'd really appreciate your help! I hooked up a new adjustable x-boost last night. I didn't see the response I expected from turning the pot. It was either very little change, or none at all. It seems like it responded a bit more when I tried more diodes.

It worked well at the current I deemed acceptable and then the next day, no power output at all.



********More details if desired***********

(was testing for a 700mW Oclaro and a 3W Nichia 445).

I used a selectable 3A test load and hooked it up exactly as the directions specified. (+ on battey to + on driver, -'s to -'s, same between the driver and test load) The DMM was hooked up to the designated pins on the test load. Not much room for error here except I had to press on the battery ends to get the wire to make good contact.

I didn't turn the pot more than 2 or 3 times in one direction, I was careful not to over do it. It really seemed to do very little much of the time.

Does it not show much change for certain #'s of diodes? I did change the jumper pin setting which selects the number of diodes used while the driver was running. I didn't see anything in the instructions about that.

I soldered the Oclaro diode with heatshrinking and took it outside, I just turned it on for moments and it worked fine. To turn it on and off I just connected the wire to the battery (This driver doesn't fit well in the host I have, wanted to try it out though as I've been really looking forward to getting my first builds going.). After I twisted the wires that go to the battery together to store it (figured that would be safer). Today the driver didn't work at all, no voltage read on the DMM whatsoever. I wonder if I used too much flux? I don't think so, but I read it can be corrosive and cause shorts. It wasn't that much but they are small boards so it is possible.

Thinking maybe just connecting the wire to the battery and holding with tape/pressure made a bad connection and that fried it or connecting the wires may been bad.


Thanks in advance for your help!

Flux is only corrosive if it hasn't been heated. Corrosion doesn't happen in the span of a few hours, anyway.

Running boost drivers without a load can damage them, so switching links while it's running is a no-no. Not sure on this specific driver, but it's generally a bad idea.

Bad connection to the power source is unlikely to damage anything.

Can you disassemble the device to poke at it with the multimeter?

Thank you!

Got it. Will disconnect before switching diode #. I can disassemble it very easily, in fact it isn't really assembled. The driver doesn't fit in the host so I was testing it out until the round one arrives. Everything is on a wood panel on my desk at the moment.

Be sure a load is attached to the output. What is the voltage input, and voltage output of the driver?

Which version of the X-Boost™ are you using?

1. Only the SXB can do 2.4A.
2. All of them need a heatsink unless the
   current is very low.
3. Red diodes have a lower voltage drop.
   Use a buck. Don't try to run them with a
   boost.

Cyp: Right now it doesn't have any output at all. Late last night in my frustration I desoldered all the leads. It is not really worth explaining why. I will put them back on, but there was absolutely no output from the driver. I measured at the test load and between it and the driver. The input was one 18650 battery, about 3.62 V.


LS: thanks for helping also.

1. It is an X boost V7 ADJ up to 1.8A. When I first tested it, the DMM read around 760mA.

2. I didn't use a heatsink at all, but I don't think that it was going long enough at any point. I didn't smell anything. (Though just for the hell off it this morning I briefly tried to see what would happen if I reversed the volt, It did get hot then but not for long.)

3. Okay, did some searching after reading this point. So it is bad because the input is higher that the output? I think that I didn't realize that red's drop so little voltage and that a buck would be sufficient. I was thinking that to run anything higher powered that 2x18650's were needed or a boost driver. Now the talk about colors makes more sense. Perhaps that was catastrophic? (a little intense of a word there, ha) I can't believe I spent so much time researching all of this and I missed a detail like that! :undecided: Seriously spent a lot of time. :cryyy: Part of me wishes I just followed a tutorial instead of selecting my own components.

I should have asked if what I was going to do was sound but I didn't want to be a nuisance with too many questions.


I find it to be weird that it was working the night before and then it went to 0 mv 0mA output the next day. It seems like it should still work. I am wondering if my twisting the pos and neg battery leads together did it. I don't know see any capacitors on the x-boost or anything that would release a charge into a sensitive component on the other side (really just making an educated guess here). Seems like I've worked on things most of my life and had the Vin + and - touch many times with no probs.


I am soldering it back together now hoping it will work.
I

Okay, let us know what happens. op:

Haha, love the popcorn. Seen it before but was pretty funny to me this time.


I just thoroughly tested it thoroughly with 2 multimeters. It is definitely D-E-D dead.

I tested a lot of different points on the board and adjusted the potentiometer. I think that is functioning fine. Whatever it is, I have no idea. It'd be nice if I could just replace a component but not likely.

Perhaps turning the potentiometer had little effect because the voltage was low? Anyone think that is likely? If not I wonder what was up. I could not find any instructions whatsoever for the X-boost. There some tutorials for random things but I couldn't find what I needed regarding the pot. Was also wondering if it is ok to turn while it is running. I would think so.

BTW LS, the trailer bit is pretty funny and I like your blu ray harvesting vid.

I don't know what others do but I never adjust a pot with power applied unless I am using non- conductive screwdrivers. But a couple complete sets of them (have to get them individually though) from Fasttech. Think they are ceramic and only about a buck each. Too easy to cause a short otherwise. Good idea to just use them regardless of whether power is applied to get into the habit so you don't rush and screw up.

Hey guys, I've got a question that I'm sure most of you can probably answer for me.
As I was reading the OP's first post, he stated that he only turned the pot 2 or 3 turns in one direction without much change.

My question is, in my very limited experience in adjusting driver pots, mostly cheap green modules, and flexdrives, I've never had to turn the pot more than a small fraction of a turn to change output.
Are there many drivers that use pots that need multiple turns to adjust the output?

BodhiSci said:

It is definitely D-E-D dead.

I tested a lot of different points on the board and adjusted the potentiometer. I think that is functioning fine. Whatever it is, I have no idea.

Click to expand...

Well, let's see, no heatsink, overcurrent,
overturning the pot, open output, shorted
output, insufficient voltage drop.

BodhiSci said:

It'd be nice if I could just replace a component but not likely.

Click to expand...

You can talk to Lazeerer about having it
repaired. I'll PM you his e-Mail.

It will be quicker for you to just buy
another driver, though.

BodhiSci said:

BTW LS, the trailer bit is pretty funny and I like your blu ray harvesting vid.

Click to expand...

Thanks.

BowtieGuy said:

Are there many drivers that use pots that need multiple turns to adjust the output?

Click to expand...

Not many. The FlexMod has them and I'm
hoping to eventually release a driver that
uses one. Hitting the "dead zone" on some
drivers will damage the driver and possibly
whatever it is attached to.

LS: I just meant what the component(s) were. Well there are certainly a number of possibile causes for malfunction due to the mistakes I made. I guess it is alright as I'm learning a lot here. Funny it had a delayed reaction in failing (leads me to think it was twisting the pos and neg inputs together to store. It was never on long at all though so I really don't think heatsinking was the issue. Could you explain what you mean by overcurrent and shorted output. I never got the output even close to it's limit, the highest was 775mV/mA maybe on 3 diodes and higher for the 4 and 5. I don't remember the number but it was not even in the ballpark of 1.8, which is this driver's max. , I don't think it was ever higher than around 960mv/mA . If you say most are single turn it sounds likely that the pot was overturned. Like I said I was careful but got little to no response, I'm thinking perhaps having too low a voltage drop across the diode\load may have affected that!? Hopefully on the next one there it will just be obvious from being more responsive. I agree, quicker to buy another, I'm not sure that it is worth the time and inconvenience to Lazeerer. He must be pretty busy now anyways since he hasn't been on in awhile. (thanks for the email)

Pman: So it sounds like it is ok, so long as it does not cause a short. I assume that you mean by touching adjacent components or even the soldering on the pot? Thanks for turning me on to those ceramic screwdrivers and the help. I am sure I could find something in lieu of them for now.

I emailed Jufran88, the maker of the 3A Selectable Test Loads (from Survival Lasers). he confirmed that it is bad to change the jumper that selects how many diodes it runs through. Didn't think about that at the time I thought maybe it went though at least the first one but no (I was able to make out the traces and figure out how it was setup, with no jumper there is no path to complete the circuit so might as well not be connected).

I have a round one arriving Friday so can give it another try. Not sure what version (#) of X-boost it is but it is also ADJ to 1.8A. Will definitely not use that with the 638. I have a Nichia 445 I can try out with though. I have a rectangular Pre-set X-drive 2.4A in the same order, but no host to put it in (waiting on it from Eghemus). I will have to buy another buck driver sounds like. What would you guys go with? I really prefer adjustable, besides the obvious, I like that they can be used with other diodes for whatever reason.

Thanks again

At 1.8A it takes less than 3 seconds to
overheat without a heatsink.

I learned the hard way trying to adjust Fasttech 532nm modules concerning the pots. Just way too easy to cause a short. That's why I say always use a non-metallic object to turn it or adjust with power off and then hit the juice again after very small adjustment is made.
BTG knows how sensitive those pots are on the Fasttech ones. Sometimes you're not even sure you adjusted it or not but you check anyways.
I would order a couple sets of them so you have them on hand if you are really getting into this stuff. It's great to bring down the frustration factor of trying to find something to use. I think it's less than $20 for 2 of each size. Of course I have 3 sets lol

BowtieGuy said:

Hey guys, I've got a question that I'm sure most of you can probably answer for me.
As I was reading the OP's first post, he stated that he only turned the pot 2 or 3 turns in one direction without much change.

My question is, in my very limited experience in adjusting driver pots, mostly cheap green modules, and flexdrives, I've never had to turn the pot more than a small fraction of a turn to change output.
Are there many drivers that use pots that need multiple turns to adjust the output?

Click to expand...

I believe the pot is a single turn and can be damaged if turning it too far in either direction...

Also, I didn't see anything about what cell you are using?

Quite often people use a cheap cell that can't handle the current demand so the results are not in regulation.

Remember that the driver must use extra current to 'boost' to the diode's voltage demand. And as the battery drains, the voltage drops/sags. So that means that the cell must provide more and more current to boost as it drains.

Highest quality cell needed. And in the case of high current settings, probably IMR needed. Which means you have the added danger of over discharging...

Pman: I checked Fasttech and I am not seeing the drivers. I'm interested in both buck and boost, also I need a continuous ground driver for a 300mW 650nm. You should make a list of essential and not so essential accessories

Jayrob: Thanks for the guidance there. I used a NCR18650B and a crap black one before that. Mostly the Panasonic B though. Pman and I were talking about them and their current output. I'd think that they should be perfect.

I got my drivers I mentioned today (x-boost 1.8 adj and x-drive 2.4) and a used triple output variable power supply which is partially broken. (Rock solid on the other vari output though, will attempt to fix first)

Will be attempting to put the 9mm Nichia 445 with the x-boost ADJ tomorrow probably. Round #2.