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I started assembling the components for the first of my stepper motor driver boards today. The one shown on the instructions on the reprap site is red, but mine are all green. The printing on mine is much less clear, too, so I have the website page saved as a file on my laptop, and I am scrutinising the pictures and text on screen rather closely.
Also, none of my boards have been printed or perhaps cut square, so the fixing holes in the corners don't line up.
I shall have to mark each fixing hole individually to mount the boards on Faith.
This is the first board on which I shall be soldering surface mount components. I began with the 0.22 uF ceramic capacitor (as it says in the text), also known as the 220 nF capacitor as it is marked on the board. Apparently. I can't make it out on my own board!
For those of you new to surface mount, this little capacitor (which I am assured is large - ha!) comes in a little strip of packaging. I tried to take a photograph, but the packaging is clear, and the components tiny, and the camera couldn't find it to focus!
You have to peel back the clear plastic film from the back of the packaging to get at the capacitor. And then it jumps right out...
it is a fawn-coloured thing, tiny as I said before (!) and I am wearing grey trousers. It jumped towards me. I had to search for it; I could barely spot it on my lap! The instructions say to colour it with a red or black pen, to distinguish it from the other similar but differently rated capacitors, but as I had only a green marker pen, mine is green. Colouring it wasn't easy, either!
Here it is. You can just about see it in the photo' (the camera clearly couldn't, or couldn't clearly!)
Oh this is going to be fun, isn't it?!On a lighter note, I've got my soldering tutorial up on the Builders' Wiki, with a lot of practical technical help from Renoir, and my purple RJ45 cable arrived..
An aside, really. I have discovered something about my Fuji FinePix camera; when the batteries are getting low (which happens ridiculously quickly), the autofocus doesn't always - it takes about 6 goes to get it to activate even when it is set to come on. That explains a lot of my blurry photographs. Also, I accidentally found a setting to increase the brightness, which makes it much easier to see on the LCD screen whether or not I have a decent photo'.
eBay delight! After yet more advice from the forum folk, I ordered some straight (not crossover) patch (ie not solid cable) RJ45 cables. I have guessed that I will need about 1m lengths for Faith.
Now I could have got these at 99p each, but that would have been boring grey, so I ordered 1 red, 1 yellow and 1 green for £1.25 each from Conquest-Computers, and 1 purple for £1.49 from Bluecharge Direct, all inclusive of P&P.
Because these eBay items are listed separately, the Conquest Computers' order went through as 3 separate transactions. Handily, they worked this out and shipped them all together in a Jiffy-style bag. I am still awaiting the purple one from the other company.
I have also ordered some penny washers from eBay, size M5 with outer diameter 25 mm. I am hoping these will be the right size for the swivel arms of the x/y/z stages.
eBay sub-total = £8.89- RJ45 cables from Conquest Computers, £1.25 each, x3 inc. P&P
- RJ45 cable from Bluecharge Direct, £1.49 inc. P&P
- M5 x 25 mm penny washers from Astley Components, £3.65 inc. P&P
So recounting costs,
running total (excluding last set of washers and screws from B&Q) = £384.66
I forgot to mention the problem I had setting up my new soldering iron stand. I had to use the fluted coil (holder) upside down, because my Maplin soldering iron has a couple of screws by the tip, making it too wide to fit in the normal way up. This necessitated using pliers to force the coil apart at the (now) bottom end in order to twist it out, and to shove it over the plastic support!
Today, I set to, soldering the noise suppressor board, and as before got part way through when I had to pause to ask a question of the forum folk; the screw terminals component had leads but also made contact with two other pads, and I wasn't sure if they were to be soldered as well. The advice came that I could ignore them, so I soldered just the leads.
When it came to soldering on the tiny tiny tabs into huge holes on the board, I was at a bit of a loss. I secured the motor against the back of the board using an elastic band (left by the postie). You can see the capacitors' outer legs left un-trimmed, for soldering to the motor casing later on.
The instructions warn you to use a lot of solder, but it was difficult to heat the large round contact and each tiny motor tab (taking care not to damage it) as they didn't fit snugly together. Eventually I had a mass of solder there, but not exactly shiny, no matter what I did.
Soldering the legs of the two outside capacitors onto the motor casing proved to be even harder. I tried cleaning the casing first, and tried to tin the casing before affixing the leads, but neither joint looks pretty, and in fact I had to re-do the second one three times. Then I affixed the cable tie to hold it together firmly, and this second joint clearly moved!
I ended up using the desoldering braid to remove the solder. That wasn't easy, either - I wasn't expecting the braid to get hot, and I found my hand getting uncomfortably hot holding it. Also, it didn't seem to wick, but I did get a blob off at a time. I wonder if that's because of using the higher temperature, unleaded solder?
I tinned the capacitor lead, and squashing the end of the lead down onto the motor with the soldering iron held parallel and on the topp of the lead (and obscuring the lead from view) and moving the iron along and off the tip of the lead as soon as the solder melted. This fourth time made contact.
Not exactly tidy, though!Still, I set the multimeter to the lowest resistance setting and used it to check from the left screw terminal to the left tab on the motor, and from the right terminal to the right tab on the motor, and both gave 0.05 ohm, so I believe I have continuity despite the problems encountered.
I guess next it will be my first try at reflow soldering....
Here is what I gleaned from extensive reading before I started to solder. I put together everything pertinent that I learnt, in my own words, and went over it afresh before starting on the opto endstop boards. You could call it a tutorial. Unfortunately, it isn't possible to grow a third hand for taking photographs whilst actually soldering, and my photo's aren't perfect anyhow, but they give an idea....
How to....
Check that you have all the right components for the board. It is a good idea to lay them out around the board, each on the respective head/foot/left/right side, to assess sizes and locations of the individual components.
Start with the smallest component on the board.
Firstly, check the component leads for signs of dirt or corrosion (see later), and clean by wiping as necessary. If the component has been shipped stuck onto tape, cut the leads alongside the sticky tape to prevent future issues with glue interfering with the solder joint.
Bend the component leads down to align with the fitting holes in the board. Check which way round the component must be inserted; with some components this doesn't matter, but with others it is critical. Insert the leads, from the top towards the bottom surface of the board, both at the same time, but do not press the component down onto the board, because that may kink and weaken or snap the leads.
For any component that may heat up in use, eg a resistor, leave a small gap so that the component is raised above the board slightly to allow air to circulate and heat to dissipate. For temperature-sensitive components, eg transistors and diodes, where excessive heat from the soldering operation can be harmful, again leave a small gap, so that a small crocodile clip or similar metal item can be attached - during soldering - to act as a heat sink and dissipate excess heat.
Bend the leads outwards away from each other slightly on the underside of the board to hold the component in place. (This picture shows a ferrite bead sat vertically on the board, but most components will be aligned between their fixing holes, known as pads.)
Cut off the leads a few mm (approx 3 mm) away from the board. Do not cut them off flush with the board. Cutting the leads before soldering prevents disturbing or damaging the finished joint.
Repeat with one or two other small components, working from the centre of a big board outwards.
Now heat up the soldering iron. Clean the tip using a dampened card egg-box (my resourceful Dad's method) or a wetted sponge (commercial method). The tip should be shiny.
Apply the tiniest amount of solder, containing flux, to the iron tip, by just touching the solder against the tip, but all around it, to prevent it oxidising. Now wipe the tip on the damp card/sponge.
If the component leads are lightly corroded, and not shiny themselves, use the soldering iron to heat the leads. Without moving the soldering iron, now touch the solder to the lead on the side away from the soldering iron.
Move the solder wire away, remove the soldering iron and check that there is now a layer of solder around the lead. This process is "tinning". "Tinned" parts will solder together well. Discard the excess solder blob on the iron tip by wiping it on the dampened card/sponge. If too much solder is applied to the part being tinned, use desoldering wick/braid to remove the excess by applying the wick to the coating, and the tip of the soldering iron to the wick, gently pulling the wick along under the iron tip as the wick becomes full of solder. Remove both wick and solder together.
On the underside of the board, use the hot iron tip to heat the lead AND the copper connection together, for just a second or two. Now, without moving the iron tip away, add a tiny amount of solder to the side of the lead by touching the solder against the hot lead and copper connection, followed by quickly adding solder, using a dabbing motion, to the side of the lead away from the iron, again down against the copper connection.
Repeat this movement until sufficient solder has been applied to create a good joint. Take the solder wire away, then immediately remove the soldering iron, to avoid boiling off the flux and creating spikes, without knocking the joint. Do not move the board until the solder joint has set.
Now inspect the joint.
The outline of the leads should be jutting out of the solder joint slightly. As the joint cools, it should have concave sides, should be flush against the copper connection, and pulled up around the component lead. The solder should not "bridge" to neighbouring connections. If using leaded solder, the joint should look very shiny; lead-free solder will look a little duller or grainier, but still shiny.
Check the joint from the top side of the board, too; the appearance here should be the same.
If the solder does not look shiny, or has not flowed around the lead well, re-melt it with the soldering iron slightly hotter, and ALWAYS add a small amount of flux, which may be contained in extra fresh solder, as necessary, so that the joint becomes shiny and complete.
Below is a picture of a row of good joints in the foreground, - this was my fourth board ever, so it isn't perfect, but the front left solder-joint is perfect, in size, shape and shininess. The brown marks you can see on some of the others are burnt flux, which can be cleaned off with a commercial cleaner or by scraping gently (eg fingernail), but in this case don't compromise the electrical contact.
Here is a close-up picture of the joint on the left in the background; this isn't good, having too much solder. You can see that the solder is convex instead of concave. However, it has made electrical contact and is a viable join. 
Here is a picture showing a bad joint; there are 2 large connecting holes in the middle of the board, and you can see that the top one in the picture has shiny solder in it, whereas the bottom one has dull solder. This would be a bad joint if it all looked like this. In this case, the solder on the other side of the board is shiny and I believe there is a sound connection there. Otherwise this would be a candidate for re-doing the solder joint.
Continue with the other joints, checking each as it is completed, before moving on to the next. Re-clean the soldering iron tip as necessary, probably after every few joins.
When the first batch is soldered successfully, continue with another batch of components, moving up in size and outwards on the board.
Finally, add a tiny amount of fresh solder to the tip, to protect it from oxidation in storage, before switching off. Store the soldering iron covered to keep it clean..
Before I went any further, I wanted to test the opto circuits I'd built, so I needed to know which pins were which on the RJ45 connector. I used this, which was the clearest description I found, with a nice easy diagram - so looking at the RJ45 jack socket on the board, with the board the right way up, the pin on the left is 1.
According to the circuit info. in the assembly instructions, pins 4 and 5 are connected together, and this is where the +ve end of my 5V power supply had to be connected, and pins 7 and 8 are connected together, GRND, and this is where the -ve end had to be connected.
Below is a photograph of my testing set-up, using 3 D cells (giving approx. 4.5V) and some alarm wire all blu-tacked together. It took some fiddling to get continuity; too much blu-tak insulated the alarm wire strands!
I stood the battery-tower up and wedged it inside a perfectly-sized cardboard box to hold it all together better. Here is a photo' of the circuit board with its optical sensor blocked with some folded corrugated card (the wire in the foreground is not actually making contact yet) , and below that a photo' with the LED lit. 
Believe me, holding the wires to get this working whilst taking a clear photo' was no mean feat!
Hoorah! All 3 circuits work as hoped, with the LED lighting when the sensor is blocked, and going off when unblocked. I am delighted! My first ever soldering was a success!
Some photographs:
here are all the packages required for the opto endstop board laid out,
and here are the individual components placed around the bare board,
and here are the undersides of the three finished items
I know the photo' is poor, what with being blurred and having terrible reflection off the auto-flash, but you can just about see the scorch mark at the resistor on the first one I did (on the left), before I swapped to a finer tip on the soldering iron.Now I need to determine which connectors are what on the "ethernet" socket and get myself a 5V power source to check all the opto endstop boards.Here is a better photo' (new batteries in the camera, daylight (of sorts)) showing the first board:
The slight scorch-mark is (on the middle resistor) just above and to the right of the central fixing hole..
I have started assembling and soldering the first opto endstop. These boards are made solely with through-hole components. My first soldering atempt on this PCB left a scorch mark on the board - note Nophead's comment about how the solder pads on the board could do with being bigger.
So I switched off the soldering iron, let it cool and swapped for a finer tip. I'm glad I had bought a set of tip replacements for my iron.
When I got to the LED, I had to ask on the forum what the instructions meant for how to get the orientation correct. The phrase was "Insert the short leg (negative) into the hole closest to the flat side of the silkscreen" - I don't know what that means, nor what a silkscreen is, in this context!
The replies came back that "silkscreen" means the diagram printed on the board (if only they'd written "diagram" instead) so the "flat side" refers to one side of the LED's almost circular diagram, ie the picture isn't completely round - there is a subtle flattening on one side. I'm hoping not all boards are so subtle....
Further information came back that I should not assume that the short lead on the LED is the negative one - it isn't universally true! But that this can be checked by using the lowest resistance range on a multimeter, and touching its black lead against the short LED lead (and the red against the other), causing the LED to light up if the short lead is indeed the negative one.
However, I found this didn't work..... but I found that it did work if I used the triangle (now I know it means a diode) symbol on the multimeter. I only considered trying this setting because I had earlier seen the triangle symbol, labelled LED1, on the circuit diagram for this board.
Looking at information on multimeters, I found that a digital multimeter may not have the right resistance range to check diodes, hence the separate diode-testing setting.
I shall have to try to remember this test before connecting up my other brand LEDs.
My first soldering looked (generally) O.K. on the rear of the board, ie the solder itself looked fairly shiny (I'm using lead-free solder, which doesn't make as shiny a join as the traditional leaded type), concave, although not exactly neat, but it looked dull on the top, and I had used too much solder in places. As far as I can tell, there is, unfortunately, no way of checking the finished board independently of any other boards.
Oh this is going to be fun, isn't it?!
