How to tune the Madmax trimpot?

[pedalinbob]

i have tried turning the pot, but nothing seems to be happening. i even turned it a total of 3 rotations, with no change in output. turned it in both directions.

im trying to detune it a bit to increase runtime.

i couldnt find the Dat2zip area that shows how to properly adjust the madmax. might have overlooked it, though.

help?

Bob

 

[dat2zip]

The trimpot has no end stops and thus will rotate around 360 degrees. It is a single turn with a dead spot.

I've only played with the trim pot on the bench when I did some testing. I hear it takes patience and careful adjustment to get it to work.

Maybe, some of the other more experienced users can help out.

 

[Tomas]

I'm another who will be attempting to adjust a 'Max to a fairly low and stable point (I need it to run in the 300-350mA range and no higher).

Hopefully someone who has experience adjusting these will offer some pointers. Even just figuring out how to determine the set point (current) one is at appears to be a considerable problem.

 

[LED_ASAP]

Those SMD trim pots are rated only for 15-20 adjustments, then the contact point gets worn out and you may never have an adjustable pot. So, decide where you want things go before adjusting the pot, and DO NOT play with it for fun. (I don't have a MM so I can't tell you how to adjust the pot properly /ubbthreads/images/graemlins/blush.gif )

 

[shankus]

I was playing with the one on my original MadMax, and found it very difficult. I ended up giving up on it. I found that it was like Wayne said, a full turn, with a dead spot.
Is this a linear, or logarithmic pot?

 

[pedalinbob]

i was trying at first to turn it in tiny increments, but after the first turn, thought maybe i needed to turn it farther.

then i thought i turned it in the wrong direction...so i went the other way.

i will try again today. i have read the threads, and someone states that to de-tune it, you need to go counter-clockwise as viewed from the BOTTOM of the pot (the bottom being the end mounted to the board).

Tomas, please keep us posted as to how things turn out (pun!). i will too.

Bob

 

[Zeppert]

I'm waiting for my first MadMax+Q3 to arrive. It is STILL in the PROCESSING stage though /ubbthreads/images/graemlins/sleepy.gif . I am glad they come almost fully cranked 'cause that's exactly what I'm looking for. I have new Powerex 2200 NiMh so I feel pretty confident that I should get decent run time.

 

[Tomas]

Once I start working on this (setting a MadMax) I will, Bob. The light that is coming with the MM installed should be in my hands in under 2 months.

If there were such a thing as a BB300 or BB333 that would be my "perfect choice" for this light (FireFly), but what I'll be trying is to throttle a MadMax down to that sort of level.

This will, for me, require some sort of jig to hold the module outside the light and power it so I can take readings of current draw (I'll be using "I in" to roughly deduce "I out" guessing about a 75% efficiency - in other words I'll be trying to adjust to about 400mA "I in" for a 300mA "I out" to the LED).

I'll be using tiny tools, one hand, a magnifier, and lots of light, but it still sounds a lot like trying to neuter a housefly ... /ubbthreads/images/graemlins/huh.gif

Oh! How long a burst can I power the MM/LS package with no heatsinking and unknown current and still feel safe that there is no chance to damage the LS?

Anyone?

 

[x-ray]

[ QUOTE ]
pedalinbob said:

i couldnt find the Dat2zip area that shows how to properly adjust the madmax. might have overlooked it, though.

help?

Bob

[/ QUOTE ]

I think this is the page your looking for (scroll about halfway down) /ubbthreads/images/graemlins/smile.gif

 

[pedalinbob]

YES! that is what i was looking for! thanks!

for some reason, i could not seem to find that page--though i had viewed it in the past.

it looks like it is turned CCW (as viewed from the top) to dim it--correct?

Bob