Uzebox SMD soldering

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JimmyDansbo
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Uzebox SMD soldering

Post by JimmyDansbo »

Hi.

danboid was kind enough to send me a Uzebox PCB and an SD card slot, but he asked me to do a video on soldering the SMD parts of the board.

I have not done SMD soldering for about 20 years and this time I am doing it with just a standard soldering iron and some flux, no stensils, soldering paste or the likes...

You probably want to watch the video at increased speed as most of the time is me ranting about the difficulties of doing SMD soldering with standard tools.
Enjoy and do let me know what I should have done differently as well as what I could have done to improve the video.
https://www.youtube.com/watch?v=S7GWMNdyopo

Note: I have not completed assembly of the board yet so I don't actually know if my SMD soldering is working...
Edit: The board has now been assembled and the SMD soldering works without any issues.
Last edited by JimmyDansbo on Fri Mar 17, 2023 11:21 am, edited 1 time in total.
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Artcfox
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Re: Uzebox SMD soldering

Post by Artcfox »

I am not a professional by any means, but I have done a bunch of soldering by hand, with and without stencils, with a hot air gun, a reflow oven, or just a board pre-heater and low temp solder.

I watched your video, and I think you can skip the gel type flux and just go for the liquid type. You have the right idea tacking down a corner, but I think you are using too much solder, and possibly the wrong style tip. A tip shaped like a flathead screwdriver might work better. Instead of the drag technique, I typically just come in perpendicular on each pin. If the tip of the iron already has solder on it, and you have flux on the board you should be able to just touch each pin with the tip and let it wick up a bit of solder from the blob on the iron. No need to add more to it for each pin; I think that is how you ended up with too much solder forming bridges.

Alternatively you could get really fine solder and lay it across all the pins where they meet the board, and then hit each pin/solder section perpendicular to the chip.

I think you have the right idea, just use less solder.

Good luck completing the build!
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danboid
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Re: Uzebox SMD soldering

Post by danboid »

Good to see the PCB and SD socket arrived!

Thanks for making that video Jimmy! I can see it didn't go perfectly but the end result looks good to me and I think that watching this video would've been enough to give me the courage to have a go myself, if I hadn't got my mate to do those two bits instead.

I have added a link to your video to the "Help, Tips & Tutorials" section of the main wiki page. At first I thought I might wait until you've finished building your Uzebox so you can verify if it works but seeing as we don't have any other Uzebox soldering videos to pick from it deserves to be on the wiki until someone creates something better.

Did the PCB arrive today then? Lets see how much faster you build your Uzebox compared to my record breaking delay and setback fest of a build.
CunningFellow
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Re: Uzebox SMD soldering

Post by CunningFellow »

drag soldering with a flat or hoof tip unless you have a lot of experience.

also use leaded solder - you need to have the technique down pretty well to succeed drag soldering with lead free.

have the tip at a shallower angle to the pins you are dragging past - so the surface tension is pulling the excess solder into the meniscus that is forming in the shallow angle in front of where you are dragging along.

As artcfox said - gel flux at the start was probably not needed. In fact unless I have a problem I don't even add flux at all, I just rely on the flux in the cores. I do always use an RMA fluxed solder (multicore 362) for this kind of thing. No-clean and crystal fluxes don't work for as long.

Also the AD723 is pretty large - so again as artcfox said - solder a pin at a time is possible. Then if you get some blobs/bridges you can drag DOWN a single pin pair to remove the blob rather than drag across the pins.
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JimmyDansbo
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Re: Uzebox SMD soldering

Post by JimmyDansbo »

Thanks for your suggestions.

Next time I think I will try to use a tip that is flat instead and I will definitely keep in mind that I don't need as much solder.
When that is said, I have gone over the pads several times to ensure that there were no solder bridges.

Now I have finished the rest of the build and am trying to flash the bootloader and fuses to the 644.
The only programmer I have is the Minpro TL866 II+ and it seems it is not supported by avrdude. Does anyone have any experience flashing the mcu with the minipro ?
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Artcfox
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Re: Uzebox SMD soldering

Post by Artcfox »

I do not. Do you have an Arduino or a Raspberry Pi? I believe you can use those with the appropriate firmware/software to act as a programmer with avrdude.
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danboid
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Re: Uzebox SMD soldering

Post by danboid »

Haha! So its only took you a day, or less than a day to build your Uzebox right, excluding flashing the bootloader? That's one helluva time diff between my multi year mess.

I didn't know you could use avrdude via GPIO so I've updated the avrdude wiki page with a link to this guide:

https://ozzmaker.com/program-avr-using- ... y-pi-gpio/

I've not tested those instructions yet myself so let us know if that guide works for you or if you find a better guide elsewhere.

I'd be amazed if Jimmy doesn't have at least one RPi or SBC with a GPIO header.
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JimmyDansbo
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Re: Uzebox SMD soldering

Post by JimmyDansbo »

I think I will break out my Raspberry Pi 400 and have ago.
This will be the first time the 400 is actually used for anything useful :-O

But it will have to wait until tonight. The day is filled with chores that needs doing...

Btw. I actually think that I have been able to flash the mcu with my minipro tl866+, but when I power the board on, nothing happens except the green LED lights up. When I press the reset button, the LED turns off, but comes back on when I release the button. The power button does not do anything at all.
(I am afraid I need to track down bad or missing solder joints to get this to work, but first I would like to be more sure that the mcu is programmed correctly)
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danboid
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Re: Uzebox SMD soldering

Post by danboid »

Don't worry about the power button. It doesn't do anything by default. I don't think its used for anything yet like, y'know, power.
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Artcfox
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Re: Uzebox SMD soldering

Post by Artcfox »

Awesome!

Just a word of caution, the fuse bits tell the AVR which clock source to use, so unless you have a breadboard and circuitry to support that clock source, it might be better to wait until you have it installed with it's clock source before you flash the fuses.
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