How long does it take? (to learn to stack 7135 chlps)

LED Flashlights – General Info
1

I was just wondering how long it took most modern to get the hang.of stacking 7135 chips I have been trying on and off now for 3 months and have went through 3 each 10 packs of 350 mAH chips, I have tried the bent down tabs ,straight tabs, soldering the big tab on the backside, using hemostats ,third mechanical hands with a magnifying glass. Lighted magnification glasses new soldering iron and still 0 out of 30 .Up to this point I have been doing basic mods by getting 17MM drivers already stacked to order and Noctigon mounted emitters and braiding the springs but that is far as I have been able to progress I know I am to stubborn to quit so I’ll keep at it once I get more 7135 chips in .I am wondering if iam wayyy behind the curve or if iam not the only one.

2

I found that a simple blob of superglue gel (slow setting not instant bond stuff) to lock the 7135 on top of the other helps IMMENSELY in holding it in place to solder the bent down tabs, took me a while of futzing with clips and holders and whatnot…once I learned that trick it made soldering em a whole lot easier…especially when you don’t have to worry about them skittering around while trying to solder.

You weren’t the only one :wink:

3

You might not want to hear this but, the first one I tried I stacked 4 chips successfully. Haven’t had a failure yet. The worst that has happened was the solder jumped to the tab next to the one I was soldering but I just cleared it away and joined it to the one below. I superglue the chip on top and that’s it. Don’t bend tabs or anything else. I use 0.6mm solder and the finest tip that my Snap On soldering iron came with.

4

You are not alone. I have broken quite many drivers before I got used to this stuff.

I did not use superglue. The way I do this is first soldering the back tab of the chip to set it in place, then only deal with the three legs.

5

I’m just about to try this, I thought you only had to do the back pin and then the 2 end pins and don’t bother with the middle one

Is that right? Or do all 3 have to be soldiered

6

You are correct, it is not necessary to solder the middle pin.

7

May I ask: If you are soldering the back tab of the chip, why would you then solder all three front legs? Isn’t the back tab the same as the front middle leg, meaning that if you solder the back tab you don’t need to solder the front middle leg?
Edit: Saw this just got asked and answered.

8

Yes, with the back tab soldered you don’t need to solder the middle leg actually. Most of the time I just soldered the outer two legs, but sometimes I just felt trying to solder the middle leg, there is nothing important there.

9

Center leg and back tab are electrically connected…ground, only the outer 2 legs need to be soldered to the pins below them, and the back tabs

10

My first driver got 3/4 chips soldered correctly. I don't like it, and that's why I've been buying those BLF FET drivers lately.

11

However some said with both of the back tab and middle leg soldered the heat dissipation of the 7135 chip might be better. Don’t know how true is it though since nobody really test this, but I guess it is not that significant after all.

12

i’ve been thinking about trying to add some 7135-chips to a couple of drivers, but i need to get a thinner tip for my soldering iron.
hopefully i’ll manage to end up in the successful group :bigsmile:

13

Hi,

Can you link to the gel you use? The ones I tried melt when I heat them up…

Thanks,
Jim

14

why there is no one selling Nanjg 105c with 16 ships

15

I think that RMM (mtnelectronics.com) might do that for you?

16

Will make a custom driver anyway you want it.he is fast and very reasonable.

17

Will make a custom driver anyway you want it.he is fast and very reasonable.

18

I thought about it , but I wasn’t sure it would work , now knowing that I’ll try that and try to solder back tab and then work forward 3 I am using a 1/32 pencil type tip are their. Any thinner tips available?

19

WarHawk-AVG,

Can you provide the above info (which gel)?

Thanks,
Jim

20

It’s pretty much all the same I think, this is what I got the other day in Wallyworld
http://www.walmart.com/ip/19289668?wmlspartner=wlpa&selectedSellerId=0&adid=22222222227000000000&wl0=&wl1=g&wl2=c&wl3=41833582510&wl4=&wl5=pla&wl6=19880599990&veh=sem

And literally…just a tiny little almost cant see it glob

I usually bend the outer legs down, then make sure they are perfect shape (be warned you can break the housing on the chip) then position them on the host 7135 w/o glue, make sure the legs line up, pick up the 7135 on top with needle nose tweezers, put a teeny dollop of super glue gel, place the top 7135 back on while still holding with the tweezers, gently press with my free hand and count to 15~

I also use a TON of flux…flux the pins, then clean the tip in a small bucket of brass wool, put a small blob of solder on the tip, hit the bottom pin and drag out past the top leg, the solder usually bonds quickly. Then repeat on the next leg, I then do the back tabs. Then I clean the bejesus out of the flux with 91% isopropyl alcohol.

rinse and repeat

I think with alot of solder flux the solder flows rapidly and the length of time you have to keep the heat there is greatly reduced, you will start learning the sweet spot of the blob you need on the tip in order to add solder or remove solder if you put too much on