Author Topic: 2 Down, 31 to go! Now taking Bets :D  (Read 10426 times)

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Offline @rt

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2 Down, 31 to go! Now taking Bets :D
« on: September 16, 2016, 03:27:46 am »

48 pin LQFP, of which 43 are connected, and 41 still need lead out.
I give odds of 75% on this board in my favour :D

 

Offline Ampera

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Re: 2 Down, 31 to go! Now taking Bets :D
« Reply #1 on: September 16, 2016, 03:36:42 am »

48 pin LQFP, of which 43 are connected, and 41 still need lead out.
I give odds of 75% on this board in my favour :D



You've got this. Time will give the perfect product. Unless you fry it with your iron.
C/C++/Java Programmer, Legacy hardware enthusiast, madman.
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Offline Red Squirrel

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Re: 2 Down, 31 to go! Now taking Bets :D
« Reply #2 on: September 16, 2016, 03:48:34 am »
Haha nice.  I've tried hand soldering SMD and gave up, my tip on my Hakko is bigger than like 3 pins combined, and I can't seem to find smaller tips in Canada.
 

Offline @rt

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Re: 2 Down, 31 to go! Now taking Bets :D
« Reply #3 on: September 16, 2016, 03:52:02 am »
I had to get a tip for this.. not what I’d use for any other project.
This is not at all sensible.. the completed Arduino compatible shield is only $10AU.
Just a challenge, if I’m successful I’ll set it in some clear potting.

 

Offline XOIIO

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Re: 2 Down, 31 to go! Now taking Bets :D
« Reply #4 on: September 16, 2016, 04:22:58 am »
I had to get a tip for this.. not what I’d use for any other project.
This is not at all sensible.. the completed Arduino compatible shield is only $10AU.
Just a challenge, if I’m successful I’ll set it in some clear potting.

Is that from adafruit or ebay? If you haven't, check ebay, you can get a pro mini for as little as $1.50 if you time it right.

Offline @rt

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Re: 2 Down, 31 to go! Now taking Bets :D
« Reply #5 on: September 16, 2016, 04:29:36 am »
Oh, I already paid $35 from out local retailer Jaycar in Australia, just to have a working one in a hurry.
I wanted to start on software already since I’ve never used any mp3 decoder.

 

Offline Karel

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Re: 2 Down, 31 to go! Now taking Bets :D
« Reply #6 on: September 16, 2016, 12:00:16 pm »
A year ago I did something similar with a TQFP100. Didn't connect all pins though...
 

Offline @rt

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Re: 2 Down, 31 to go! Now taking Bets :D
« Reply #7 on: September 16, 2016, 12:46:19 pm »
Lol nice :) Because you didn’t need many pins or didn’t finish it?
They look like just ground pins on a copper ground plane, but I don’t know everything I’m seeing right.
It also looks like a bunch of construction workers are holding up the chip if you look at it that way :D

The manufacturer has relieved me of connecting another two pins, and potentially more, but I’ll see how I go.
 

Offline JPortici

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Re: 2 Down, 31 to go! Now taking Bets :D
« Reply #8 on: September 16, 2016, 12:56:45 pm »
Haha nice.  I've tried hand soldering SMD and gave up, my tip on my Hakko is bigger than like 3 pins combined, and I can't seem to find smaller tips in Canada.
not a problem. drag soldering + flux and copper strip. no chip have ever died on me, yet
 

Offline @rt

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Re: 2 Down, 31 to go! Now taking Bets :D
« Reply #9 on: September 16, 2016, 01:31:19 pm »
I totally missed that. This is not surface mount soldering!
Just one of Dave’s videos could change your life. This tip is wider than 3 pins too!
 

Offline Red Squirrel

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Re: 2 Down, 31 to go! Now taking Bets :D
« Reply #10 on: September 17, 2016, 07:25:38 am »
My issue when I tried was that I was doing it in free air, I imagine it's easier on a board as solder tends to want to not flow on solder mask and you have a proper area for chip to stay put once you can tack an end.  Been meaning to learn Ki Cad so I can draw some breakout boards and have them made.  I have lot of components I want to play with but ridiculously under estimated how hard it would be to dead bug them when I originally bought. 
 

Offline rstofer

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Re: 2 Down, 31 to go! Now taking Bets :D
« Reply #11 on: September 17, 2016, 03:06:27 pm »
Haha nice.  I've tried hand soldering SMD and gave up, my tip on my Hakko is bigger than like 3 pins combined, and I can't seem to find smaller tips in Canada.

Put some paste flux along the pins.  Just run a string all the way around the chip using a syringe (like the paste comes in).

Using a fairly large tip, put a small blob of solder on the tip and run the tip across the pins.  When you run out of solder, apply another blob.

Seriously, you don't solder these things pin by pin.  You 'drag solder' the entire package.  The package in the picture has fairly wide pin spacing.  It will be unlikely you would get a solder bridge.  If you do, a little solder wick will pull the solder off.

You would usually tack to opposing corners before starting the drag operation.

 

Offline matseng

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Re: 2 Down, 31 to go! Now taking Bets :D
« Reply #12 on: September 17, 2016, 03:07:00 pm »
Like 10 years ago I did this mega168/smd to dip hack by soldering 32 wirewrap wires to the pins down to the socket. Unfortunately it seems like I forgot to take a picture of it before bukkakeing it with hotsnot... ;-)

 

Offline amyk

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Re: 2 Down, 31 to go! Now taking Bets :D
« Reply #13 on: September 17, 2016, 03:09:54 pm »
 

Offline homebrew

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Re: 2 Down, 31 to go! Now taking Bets :D
« Reply #14 on: September 17, 2016, 09:08:23 pm »
You have totally missed out the good old Elm Chan ...



http://elm-chan.org/docs/wire/wiring_e.html

I guess I'll never be at that level of perfection ...
 

Offline rob77

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Re: 2 Down, 31 to go! Now taking Bets :D
« Reply #15 on: September 18, 2016, 12:18:41 am »
 
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Offline @rt

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Re: 2 Down, 31 to go! Now taking Bets :D
« Reply #16 on: September 18, 2016, 04:44:56 am »
Oh no! One of the leads on that BGA is broken!
Those are things of beauty, unlike mine :D

I haven’t wrecked it yet though, despite how it looks (unless ESD or dwell time has killed it).
The pins can be staggered, either lift a pin, or not, so it’s really a 3D object that you can’t see here.

3/4 done, the last row is the analogue output and supply where I’ll try to be more careful.

 

Offline @rt

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Re: 2 Down, 31 to go! Now taking Bets :D
« Reply #17 on: September 18, 2016, 07:53:30 am »

Hopefully get to test tonight :)

Question: Is the potting used for China chip on board any different than the self mixing stuff sold at RS in small quantities?
Or any different than the potting used to fill enclosures?

 

Offline SeanB

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Re: 2 Down, 31 to go! Now taking Bets :D
« Reply #18 on: September 18, 2016, 08:40:23 am »
No different, most PCB potting compounds will work, but I would there on your board rather use a flexible potting compound, so that thermal stress does not crack the leads off the solder.

If it works then first clean the flux off, test again and then use a blob of a flexible compound, like Pratley flexiseal, to encapsulate it, or a flexible conformal coat.
 

Online blueskull

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Re: 2 Down, 31 to go! Now taking Bets :D
« Reply #19 on: September 18, 2016, 08:49:55 am »
Question: Is the potting used for China chip on board any different than the self mixing stuff sold at RS in small quantities?
Or any different than the potting used to fill enclosures?

COB epoxies are different than board potting epoxies!
COB epoxies are designed to minimize CTE mismatch, and are designed with controlled modulus -- hard enough to protect bonding wires, and soft enough not to rip off bonding wires due to CTE mismatch stress.
Potting epoxies are designed to have better thermal properties (insulative or conductive) and harder to peel off (to protect design IP) and absolute low cost.
Potting silicone materials are designed to have high insulation voltage, low uncured viscosity and low ion contamination (especially sodium ion and similar small radius ions), for high voltage applications.

For your case, since you have packaged chips and long copper wires are quite flexible, you should not use COB compounds. You should consider MG Chemicals 832B.
 

Offline @rt

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Re: 2 Down, 31 to go! Now taking Bets :D
« Reply #20 on: September 18, 2016, 09:19:17 am »
Ok :) Thanks for the replies. I’ll have to do something quick. It’s corroding as we speak :D
Is the resin in solder to be removed only because it won’t stick?
This is assuming it’s not burned to carbon, and could conduct.
I could wash it in alcohol which won’t remove everything, but there are plenty of places I can’t touch.
 

Online blueskull

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Re: 2 Down, 31 to go! Now taking Bets :D
« Reply #21 on: September 18, 2016, 09:48:05 am »
Is the resin in solder to be removed only because it won’t stick?

If the compound I recommended won't stick to cured flux, MG Chemicals wouldn't stay in business for so long ;).

This is assuming it’s not burned to carbon, and could conduct.

Unless you baked it for too long. Usually trace amount of carbon in no clean flux will be separated and suspended in cured flux. Cleaning is not a must.
The use of water soluble flux calls for cleaning as the chemicals inside (especially ammonium chloride) may corrode metal.

I could wash it in alcohol which won’t remove everything, but there are plenty of places I can’t touch.

Use ultrasonic cleaner, or ultrasonic toothbrush. I use a Philips Sonic Care.
Also, 1:1 IPA+acetone works better than IPA along. Though acetone has irritating smell, it does less harm to your body.
Some US states even banned the use of 75%+ IPA and demands the use of other solvents.
IPA sucks water from your skin, and creates wrinkly and flaky hands. Always add other solvents like acetone, diethyl ether or ethyl acetate.
Do not add water as solubility of flux decreases a lot as water concentration goes up.
 

Offline @rt

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Re: 2 Down, 31 to go! Now taking Bets :D
« Reply #22 on: September 18, 2016, 06:28:53 pm »
It’s just increased a lot lot in personal value now it works :D
Not first go, but after fixing a mistake in installation (not this module itself) swapped SPI clock and data out,
and also the crystal oscillates intermittently when set up with the 33pF cap values in the data sheet example.
It works reliably now I have only disconnected one of them from ground which surprises me.
I was going to go all the way to swapping both for 22pF, but the first disconnection I made had it working reliably :)

Now it also means I should spend the money on good goop since I’d really get into Eagle CAD more than do this again,
So I’ll look into the MG Chemicals, so long as it’s not an unreasonable minimum to buy.
« Last Edit: September 18, 2016, 06:31:38 pm by @rt »
 

Offline @rt

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Re: 2 Down, 31 to go! Now taking Bets :D
« Reply #23 on: October 08, 2016, 01:42:56 pm »
I never did follow this up... bam!! :D It’s audio coupled through earphones sorry!
 

Offline bitslice

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Re: 2 Down, 31 to go! Now taking Bets :D
« Reply #24 on: October 08, 2016, 03:00:26 pm »
why would anyone do that?  :wtf:

just buy the relevant PCB adapter, they are available for every package type

 
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Offline zapta

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Re: 2 Down, 31 to go! Now taking Bets :D
« Reply #25 on: October 08, 2016, 04:10:04 pm »
why would anyone do that?  :wtf:

just buy the relevant PCB adapter, they are available for every package type

And they are very cheap on ebay.   E.g. 5 units for $2 shipped  http://r.ebay.com/wxqq6I
Drain the swamp.
 

Offline @rt

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Offline Karel

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Re: 2 Down, 31 to go! Now taking Bets :D
« Reply #27 on: October 09, 2016, 06:26:17 am »
just buy the relevant PCB adapter, they are available for every package type



I never used them for the reason that I can't put the powerline decoupling capacitors close enough the chip.
 

Offline iampoor

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Re: 2 Down, 31 to go! Now taking Bets :D
« Reply #28 on: October 09, 2016, 08:11:41 am »
why would anyone do that?  :wtf:

just buy the relevant PCB adapter, they are available for every package type



Some electronics hobbyist's have masochist tendencies.  >:D
 

Offline fubar.gr

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Re: 2 Down, 31 to go! Now taking Bets :D
« Reply #29 on: October 09, 2016, 10:12:41 am »

Hopefully get to test tonight :)

Question: Is the potting used for China chip on board any different than the self mixing stuff sold at RS in small quantities?
Or any different than the potting used to fill enclosures?



Kudos for making it work, but I personally wouldn't follow this approach.

In my opinion for a circuit of that complexity it would be much simpler to design the PCB on a CAD package like eagle or kickad and order the board through a service like OSHpark.

Offline @rt

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Re: 2 Down, 31 to go! Now taking Bets :D
« Reply #30 on: October 09, 2016, 10:41:32 am »
Thanks :) I desoldered the chip from a perfectly good China module :D

I think it’s a bit better than the adapter board could turn out, but I should have followed the suggested layout of a ground plane.
The adapter boards here are a bit better because they are made for the exact 48 pin LQFP only, and are also smaller.

 


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