Just For LM2596 Users

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hificat101

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All the LM2596 preassembled that I have bought use a 10K pot, I have replaced these with a 10k, 5k, or 3k and all work. I have not tried replacing the R as it is tiny and I don't have the eyesight or talent to do it.

So without the resistor, are you having a problem with top end voltage? I'll give her a shot with a 5K Bourne thumbwheel when my boards finally get here. Thanks you rock.

Not positive; but I think it was mentioned that a 5KΩ pot will give a more usable range.

Sorry, I may have missed it. All the talk of sexy post women may have gotten me flustered. :)
 

hificat101

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heh, heh. Wrote out my response, then got distracted
Flying%20Bird.gif
and thought I had posted it. Got back to this page and saw that I hadn't; posted and BJ's was already there. I think I may need some Ritalin or something :D

I think that may have been what happened to me before if I missed the 5K post. I still say it's Quig's post woman's fault. I may check housing prices north of the border later.
 

BJ43

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I was thinking about that just last night BJ (the CB mike mod has me thinking :))...could you not just lay a solder bead over the PCB R (negating it) and go to an external R in series with the trimmer?
Guess that would work but my main reason for changing the pot was to get a better "Knob", so I really didn't try to change any resistors.
 

TommyO

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LatestLM2596Mod.jpglatestLm2596Mod01.jpg

This is another Radio-Shack 4AA box mod I put together today. I like the 4AA boxes, very easy, you do need to swap out the on/off switch tho for a higher amp one. I didn't bother drilling a hole and putting the potentiometer adjuster screw through, the box is easy to pop open and adjust if needed, and this one is for my use anyway.
 

WillyB

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This is another Radio-Shack 4AA box mod I put together today. I like the 4AA boxes, very easy, you do need to swap out the on/off switch tho for a higher amp one. I didn't bother drilling a hole and putting the potentiometer adjuster screw through, the box is easy to pop open and adjust if needed, and this one is for my use anyway.
Not really so much a "higher amp" problem. If you plan on using the switch it's more of a need for a better constructed one. It's the chintzyness that is the on/off's Achilles heel. These switches aren't really switching like the fire switch is. There is no burst of current, and no arcing involved, unless you were to hold the fire button down when you turned it on. With that assembly you will be operating at <2A for the most part. In the 'on' position I have been unable to measure any loss with my meters across the switch contacts.

I'm old school (and lazy). I never use them, I've always just loosened the atties.
 

WillyB

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Well if you've noticed the trimmer/assembly has a very wide range, 1.23V-30V. How many will we be using? About 2V? Cranked all the way up the highest unloaded volts possible are about ~5.5 with a pair of cells due to the dropout voltage. So if the trimmer was fully cranked high it would take a whole lot of turns to get it to actually start registering below 5V. The same is true from the low end.

Try again and crank from stop to stop see if you eventually hit the 'zone', do note it's a relatively small zone once you get there. The adjustments will then be rather abrupt.

This is a similar example of what happens, with a poorly designed set up (this is a one turn though).

raidy_impb2_range_.jpg
 

Quigsworth

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So can I hook a Meter to it and turn it ill it registers? and is Right going higher?

Yup, clockwise is + V and yup, the trimmers on these blow...not sure what I hate more, trying to find that stupid little screw driver you use to adjust the trimmer, the 23 turns to get it to the neighbourhood of what you want or once you do, a 1/4 turn makes it jump .5v's
..:laugh:
 
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