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2 hours ago, ralphb said:

tps.jpg.9ed22bbc83809f4cddfe629b53b4ab32.jpg

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I have 4 or 5 more of these ICs, let's hope I'm more successful with the next board! 🙈

Good luck!  With aging eyes, components getting ridiculously small, and no nearby Radio Shack available for parts, I'm no longer messing with hardware.  I'm a mid 70's - early 80's (through-hole) guy.   Sadly in it's later years Radio Shack could not even be counted on for parts anymore.  A couple of years ago @COREi64 was designing and planning to make a 3D printed P-Box Kit type case, I guess that never worked out.  I had plans for a "final project" that I've wanted to make since my youth, but never did, I guess I never will now.

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I found this information...

One of the components on my board is a 2x2mm accelerometer with 10 pins. The pins were so small that I was not able to individually dip the pads. After some trial and error of having to little or too much solder I figured out an (almost) fail-proof method. You take a tiny bit of solderpaste and apply it in between and on the sides of the pad. The capillary action when soldering will make sure that all the solder is pulled onto the pads and you're sure that you didn't add too much solder. To help this action, I like to apply a little extra droplet of flux. This really makes the component float and pull towards the right pads.
When the solder and flux is in place, simply put the tiny part in place and you're ready to do the actual soldering!

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On 10/25/2020 at 8:06 PM, GDMike said:

I found this information...

The solder paste should already contain flux, but I guess an extra droplet doesn't hurt.  But what I image will happen is that the flux evaporates first, before the solder becomes liquid.

 

You should be able to see the capillary force align the part, but my lighting with the heat gun right on top isn't that great (EDIT).

Edited by ralphb
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There is a man who does YouTube videos on macbook repair. He shows how to solder smd stuff using Flux to help in the process. Helped me to repair one of mine. The Flux doesn't burn off if you place enough in the area.

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I’ve practiced tacking down two corners with an iron before using solder paste. Cuz mine sometimes sail away with the hot air flow, as the paste starts to liquify. Sailing, on the solder sea...
 

I haven’t tried tack Flux, but I hear it helps with the chip skating. 
 

 

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15 hours ago, RickyDean said:

There is a man who does YouTube videos on macbook repair. He shows how to solder smd stuff using Flux to help in the process. Helped me to repair one of mine. The Flux doesn't burn off if you place enough in the area.

SMD parts not a problem; almost all SDD ICs are SMD (see the main controller to the left and down).  What is a problem are BGAs and company.  I do have a small reflow oven from China, but its temperature is too high for the step-down regulator.

 

Flux is a must for non-BGA SMD ICs, since you need it to cover the pins evenly with solder.  I doubt that it will help for hot hair, especially since it took me more than 10 minutes to heat everything up, which would make the flux evaporate.

 

There are low temperature solder pastes containing Bismuth, but they produce brittle connections.

 

Anyway, I think I just need more practice.  The boards aren't lost with a bad solder job, just the regulator.  And Digikey has thousands of them ... 🙂

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14 hours ago, FarmerPotato said:

I’ve practiced tacking down two corners with an iron before using solder paste. Cuz mine sometimes sail away with the hot air flow, as the paste starts to liquify. Sailing, on the solder sea...

So far I didn't have problems, probably because I reduced the air flow.  But I'll look that up!

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Ha, it seems like it did work -- IC soldered, no shorts.  Got rid of the paste, though, and instead pre-soldered all pads.  Much easier, and also much quicker. 👍

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While I could solder all available parts -- ICs and inductors -- without a short, the circuit just didn't work.  Maybe not all IC pins were connected, or I thermally killed the inductor -- I have no idea.  So I decided to use a different, more easily soldered IC.

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After that, I spent two weeks to select all necessary parts for the new layout (some datasheets just suck).

 

I also need to make one additional change to the general I/O port, as it is connected directly to the controller.  Thus, draining to much current via the port could damage the heart of the SDD 99.  I therefore plan to add two buffer ICs that would shield the controller from potential damage.  I'd use replaceable through-hole ICs, but I might not have the space required left on my board.

 

I'll keep you updated, but since I have to have another board made, I won't make in time for Christmas. 😩

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On 10/13/2020 at 12:50 PM, ralphb said:

No, it still takes some time.  Next week I will build the sidecar, then test it, and work on the firmware a little.  Then I can send out a few boards for beta testing.  If everything is OK, I can order some assembled boards, which are then for you.

 

If the built sidecar works, I can also start designing the PEB board, which keeps the main logic intact, but needs a new power supply and a reordering of connectors.  Maybe some connectors have to be removed.  Once the design is ready, the process will repeat.

 

Thus, the sidecar will be ready before the PEB card.

Looking forward to both! Thank you.

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Bad news and good news.

 

The bad news is that the new power regulator (that is easy to solder) is way to big.  Just the inductor is 1 square cm in size, which doesn't sound like much, but is bigger than the entire old layout.  So, this doesn't fit easily.

 

The good news is that I finally managed to solder the old power regulator with the last board I had, using the low-temperature paste.  This paste must not come in contact with lead, so I cannot desolder and retry my first 7, leaded attempts.  In fact, it's difficult to tell which board uses lead and which does not, which means for now that I only have one good board.  But anyway, I have this board to work on, and I'm redesigning the layout to add two more ICs that protect the I/O port.  The plan is that the new board will be used for beta testing.

 

I'll be back when I got the new boards ready.

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