Open Panzer

Open Panzer Help & Info => Open Panzer Help => Topic started by: LukeZ on August 09, 2017, 02:24:46 PM

Title: Assembling Boards by Hand
Post by: LukeZ on August 09, 2017, 02:24:46 PM
I know several people are planning or have mentioned building boards by hand, and I've gotten several messages on this topic. I think we need a public place to discuss this.

Most people are not going to want to attempt hand builds, but for those that do here is a place to discuss your experiences and ask questions. It doesn't matter if you are building the TCB, Scout or Sound Card, post here and I will try to help as best I can.

Good luck!

Title: Re: Assembling Boards by Hand
Post by: Thor91172 on August 10, 2017, 01:19:23 PM
Hopefully this will help others.  Please double check for errors.

John
Title: Re: Assembling Boards by Hand
Post by: LukeZ on August 10, 2017, 04:24:36 PM
John that looks good. R1 is named "P1" but otherwise it looks about right.

When I assemble these, I usually set out before hand all the components, and the small things like resistors and capacitors I've written on the tape their values. For that reason when I assemble it is usually faster for me just to know what value goes where, than what part number, at least for the resistors and small caps. Larger items of course you can tell where they go just by looking.

Here is an alternate version with values listed for most parts, and part numbers for others. Maybe this will be useful as well.
Title: Re: Assembling Boards by Hand
Post by: dannydeleon on August 11, 2017, 04:19:27 PM
Hi Luke,

I have ordered the PCBs for both the Scout and the Sound card from OSH Park. I see that the Scout have U1, U2, Q1 and Q2 with solder pads under them while the Sound Card only has C6. Will a hot air rework station suffice to solder these or do I have to use a reflow oven for both or can I just use the hot air station for the sound card?

Thanks,
Danny
Title: Re: Assembling Boards by Hand
Post by: LukeZ on August 11, 2017, 05:20:36 PM
Hi Danny, I've never owned or used a hot air station so I can't say how it compares to a hot plate/oven. My impression has been that hot air is used for re-working individual components rather than for bulk assembly but again, I have no experience with them so what do I know.

I'm inclined to say a hot plate is going to be easier and more consistent, but regardless you're going to have to use something other than a soldering iron. And if you're going to reflow any of it, just reflow all of it, it will be much easier.

Also - C6 on the sound board is just a regular capacitor. The two components that can't be soldered by hand on that one are actually U1 (the amp) and the SD card adapter.
Title: Re: Assembling Boards by Hand
Post by: johnnyvd on August 12, 2017, 03:03:09 AM
I would recommend using a reflow oven. The temperature profile of the solder is quite precise. And the SMD components need some time to "settle".

Currently i'm building a reflow controller for a infrared oven. Here's the blog of the guy that developed it: http://andybrown.me.uk/2015/07/12/awreflow2/

10 PCB's are on the way from https://www.seeedstudio.com/fusion_pcb.html most of the parts can be easily aquired at ebay or aliexpress.

I will post updates in this thread, but because of shipping times these will take some time  ;)

I have added the BOM for the Reflow controller as the one on Andy's website is not very "complete"..
Title: Re: Assembling Boards by Hand
Post by: LukeZ on August 12, 2017, 12:26:15 PM
Reflow ovens are great and the DIY controllers are very cool and fun. However, you don't need all that stuff if you don't have the time or money. I've assembled all my boards on hot plate that cost less than $20 at the grocery store or Amazon (https://www.amazon.com/gp/product/B00C8C5I7I/ref=oh_aui_search_detailpage?ie=UTF8&psc=1).

For a temperature controller I use my thumb and forefinger on the knob. I try not to let the temp get above 200* Celsius because it's easy to remember and the paste I use melts at 183* (Mechanic MCN-300 (https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313.TR0.TRC0.H0.XMechanic+MCN-300+.TRS0&_nkw=Mechanic+MCN-300+&_sacat=0) for a few bucks on eBay).

I've used a cheap IR thermometer to monitor temps. It works ok. Later I "upgraded" to a thermocouple on my multimeter. On the cheap plates I've used, somewhere around the "Low" setting is all you need, they get pretty hot. If you're not paying attention you can burn your board.

Heat it up, wait till everything flows, then unplug and let it cool. We're not building anything especially delicate or complicated, so the crude approach works just fine.

If you can do it better then by all means! But for others not inclined, the quick and dirty method works too.
Title: Re: Assembling Boards by Hand
Post by: jhamm on August 12, 2017, 01:52:50 PM
Luke,
i am impressed
On such a simple solution I would not have come!
Title: Re: Assembling Boards by Hand
Post by: johnnyvd on August 12, 2017, 03:47:19 PM
Check this overview of reflow possibilities: https://www.sparkfun.com/tutorials/59 get your fryingpan ready for some reflowing!
Title: Re: Assembling Boards by Hand
Post by: fuchstraumer on August 16, 2017, 11:58:26 AM
I've been looking at assembling some of these boards by hand: it is fortuitous that I have two tanks to refurb, since OSH park requires 3 boards... and clearly that 3rd board is a sign I should order another tank (been thinking about getting a Leopard and working on some kind of stabilizer)

Anyways, Digikey is pretty critically out of one component in particular: BAT54S-FDICT-ND, the diode for the recoil trigger. I've not been able to find any alternates: any similar models have the wrong diode configuration. Any go-to alternates? Next best option I found was https://www.digikey.com/product-detail/en/diodes-incorporated/BAT54STA/BAT54SCT-ND/243050 (https://www.digikey.com/product-detail/en/diodes-incorporated/BAT54STA/BAT54SCT-ND/243050), or the BAT54SCT-ND. Its got twice the leakage current, but should that really be a tremendous design concern in this case?

Otherwise I've been able to source alternates for the sound card, and I'm going to get a digikey cart/csv sheet for the scout later today. I've not done SMD stuff in a long time, but I'll probably be able to use the reflow oven at work (hopefully, working on space-grade stuff here means there's some red tape and regs about personal projects)
Title: Re: Assembling Boards by Hand
Post by: LukeZ on August 16, 2017, 12:09:59 PM
For reference this is D13 on the schematic, here is the original part specified in the BOM: BAT54S-7-F (https://www.digikey.com/product-detail/en/BAT54S-7-F/BAT54S-FDICT-ND/755493).

The alternative you linked to would work, but DigiKey is also showing it as 0 stock.

Instead I would use this direct replacement, over 165k in stock: BAT54S (https://www.digikey.com/product-detail/en/fairchild-on-semiconductor/BAT54S/BAT54SFSCT-ND/458930).

Title: Re: Assembling Boards by Hand
Post by: LukeZ on August 16, 2017, 12:37:59 PM
I updated the TCB bill of materials on the Downloads page with the in-stock diode.
Title: Re: Assembling Boards by Hand
Post by: Lotuswins on August 22, 2017, 11:09:52 PM
Luke,

What is the white disk material (and square clear) between the hot plate and the boards?? Is it to disperse the heat, making it more even over the boards?  And where do you measure the temperature? on the board, the white, or?? 

thanks, Jerry
Title: Re: Assembling Boards by Hand
Post by: LukeZ on August 23, 2017, 12:22:43 AM
Jerry, that's just a piece of aluminum foil. Absolutely not required and it does nothing to help distribute the heat.

The solder paste is a mixture of flux and solder balls. As it melts the flux often finds its way through holes in the board (called vias) and can stain your hot plate, and leave unsightly marks on the bottom of your PCBs as it burns (it will leave unsightly marks anyway, but not so bad with the foil). I put aluminum foil down to keep things clean in case I want to use that hot plate for food some day. :)

If you are using an IR thermometer you can point the beam at the board surface since that is the relevant temperature to measure. Since I have taken to using a thermocouple I just put it on the hot plate surface since obviously it can't go on the boards.

You will quickly realize there is nothing precise about this process. Temperature control on these hot plates is very crude. As long as you don't overheat things, you will be fine. You can easily see with your eyes when the solder begins to flow, at that point you know you don't need it any hotter. 

The best way to prevent burning is to bring the temperature up gradually. The hot plate will heat up much faster than the boards sitting on its surface, and the hot plate also cools down very slowly (the heating surface is typically made of cast iron which holds heat for a very long time). What this means is that while you can always make the plate hotter, once it reaches a given temperature you can not reduce the temperature anytime soon. If it gets too hot you are in a bad situation, and if you don't watch the temp closely it can easily get away from you and there is no way to bring it back down. The boards will be too hot to touch so you won't be able to remove them by hand, and anyway jostling them could cause your components to come loose.

So turn on the hot plate for a short bit, then off. Monitor the temp. Let it go up slowly. Turn the adjustment knob to a low enough setting that it is cycling itself below your target temperature, and only increase the setting gradually.

It doesn't matter how quickly or slowly the temp rises, but doing it slowly helps you keep things under control and makes it less likely you will overshoot and burn something.

As I say, when the solder starts to reflow you will clearly see it. That usually happens around 200* celsius. At that point you don't need it any hotter. Just maintain that temp until every contact has reflowed (turned shiny) and you're done.

After you do this once you will understand how easy it is. Trying to explain it in words makes it sound more difficult than it really is.

Title: Re: Assembling Boards by Hand
Post by: Ja80 on November 19, 2017, 12:51:16 PM
Good afternoon. First congratulate Luke for this great job. I ordered some scout pcb (rev.10) to seed, soldered the components with a hot plate as recommended. Burned the 328p atmega through the isp using an arduino nano and the arduino ide as (arduino as isp) then with the same arduino as cable ftdi and uploaded the program with open panzer. I think it went up well since it did not No error message. But a doubt arises when I connect the scout to the tcb by the serial port following the letters of the tcb and the scout (tx-rx- gnd) these are not in the same order on the two plates. as the plates mark, the red LED lights up intermittently and does not respond to any order of the control. but if I connect the cables in the same order as shown in the tcb, the blue led lights steadily, but does not respond to the movement of the stick, but if I move a wheel of the station to which I am assigned in a position the lights and in another cannon shot. When I put the firing position (if I have the airsoft gun disconnected) one of the engines moves a little towards a direction. If I have the gun connected it shoots and at the same time tries to move the engine but much less than if it is not connected and when this happens the blue led of the scout turns off and the red one turns on 4 times. I have to say that I do not have sbus or ibus station. if not a ppm adapter that transforms the signal from my standard receiver to ppm. the movement of the tower works and the lights on and off. if you can tell me if it's a problem with the station or the scout. a greeting sorry for the billet
Title: Re: Assembling Boards by Hand
Post by: Ja80 on November 19, 2017, 01:05:44 PM
Images
Title: Re: Assembling Boards by Hand
Post by: LukeZ on November 19, 2017, 03:14:36 PM
Ja, you need to swap the red/yellow wires on the Scout side in your picture. Here is how it should be:

TCB->Scout
GND->GND
TX->Rx-I
Rx->Tx-O

Also see the Wiki page (http://openpanzer.org/wiki/doku.php?id=wiki:scout:start#functional_overview) for a description of what the blinking LEDs mean.

If the Red LED is blinking slowly, it means the Scout has not received a signal yet. If the Blue LED lights steady, then you are receiving a signal, so that is good.

If the Red LED blinks 4 times, it means the Scout has stopped the motors because of low voltage (<6 volts). Do you have a battery connected to your Scout? The Scout will turn on just with USB power but it will not be able to run the motors from USB.

If you want to check the Scout all by itself to make sure it is working correctly, just attach a standard RC radio to the RC inputs (disconnect Scout from TCB). If the motors will work from RC control then you know at least the motor driver chips are good.
Title: Re: Assembling Boards by Hand
Post by: LukeZ on November 19, 2017, 03:29:52 PM
This is how you should power the Scout/TCB. This picture shows earlier prototypes of the boards so the connectors are slightly different, but the connections are the same.

Connect your battery directly to the Scout using the screw terminals. Then power the TCB with a jumper cable from the Scout to the TCB.
Title: Re: Assembling Boards by Hand
Post by: Ja80 on November 22, 2017, 02:46:16 AM
Good morning.
- Yes, I have connected the battery to the scout and this food tcb.
- E connected the scout to a standard receiver rc and only works the engine on one side.
the RC2 input works and the M1 motor works. (in one direction it works well and in the other it only turns slowly). E watched with the multimeter, without acting on the remote and the driver on the M1 side gives me a reading of 3v and the one on the M2 8v side. So I understand that the latter must be wrong. true?
Title: Re: Assembling Boards by Hand
Post by: LukeZ on November 22, 2017, 05:09:21 PM
Ja, the RC2 input should control M2, so how do you know RC2 works if M2 does not?

Without acting on the remote, the output of both M1 and M2 should be 0 volts (motor stopped).

My best guess is that you have a short somewhere on the board, perhaps multiple shorts. Hopefully there is no short across the pads on the underside of the motor chips, because those are impossible to fix without removing those chips.

Most likely there is a short between some pins either on the ATmega (processor) or the motor chips. Check them very carefully (if you have a magnifying glass that will help, I use something like this (https://www.amazon.com/gp/product/B0015IP380/ref=oh_aui_search_detailpage?ie=UTF8&psc=1)). If you see any pins that are touching you can fix it with a soldering iron. Applying flux first will help the solder to separate.

Troubleshooting these problems can be frustrating I know. Hopefully you bought enough parts to make more than one board! It probably doesn't make you feel any better, but I have ruined many boards myself during assembly...
Title: Re: Assembling Boards by Hand
Post by: Ja80 on December 07, 2017, 12:50:14 PM
desisti of that table, try to mount another, this almost got it but I did not realize and I had two pins of a vnh2sp shorted and broke (smoke).    :'( :'(                  I have to change it if the rest still works
Title: Re: Assembling Boards by Hand
Post by: LukeZ on December 07, 2017, 01:29:22 PM
Sorry to hear you've had so much trouble. Sometimes a short can be fixed without damage but when you see smoke that is not good. Replacing the VNH2SP30 is also very difficult because you can't desolder it by hand, it must be re-flowed which risks removing all the other components as well.

I probably should have made a disclaimer somewhere, but guys, if you are assembling boards by hand please be prepared to lose a lot of money if you are not experienced or just have your share of bad luck. It is not always an easy job, though you can get better with experience.
Title: Re: Assembling Boards by Hand
Post by: Ja80 on December 07, 2017, 03:19:13 PM
Do not worry, it just lacked that with the work you carry you had some responsibility. When I got into this mess I already knew what could happen. I will keep trying, I still have plates and some component, desoldering I will try to have air if I get it.
Title: Re: Assembling Boards by Hand
Post by: Ja80 on December 10, 2017, 04:21:46 PM
Good afternoon, in the end I did not manage to fix that table when releasing vnh2s with hot air was not enough heat and some pad was ripped so I discarded the table >:(. But the fourth was the good one. finally I have a functional scout.
Title: Re: Assembling Boards by Hand
Post by: LukeZ on December 10, 2017, 06:01:24 PM
Yes, I have not had much luck with hot air rework because I always damage something else worse. But I do no have a hot air station, only a heat gun. :)

I am sorry you had so much trouble but like I said before, I have definitely been in your shoes. Now that you have acquired all this experience you could probably build many more with no problems.

I hope you like your Scout!
Title: Re: Assembling Boards by Hand
Post by: Ncartmell on January 22, 2018, 01:19:20 PM
Hello,

This weekend I was in a local store and they were selling small 1kW temperature controlled ovens. They were compact and had a glass door I wondered if they would be suitable for pcb build or should I stick with a hotplate.

Thanks

Neil
Title: Re: Assembling Boards by Hand
Post by: LukeZ on January 22, 2018, 02:08:34 PM
An oven will work just fine and theoretically even better since you will get more even heat. Just be sure you really can control the temperature.

For the stuff we're doing it doesn't really matter and for someone reading this who doesn't want to spend the money on an oven, rest assured a hot plate will work fine. But if you want to get an oven go for it.
Title: Re: Assembling Boards by Hand
Post by: pandknz on August 31, 2018, 05:10:11 PM
Luke, your dedication to this project deserves an applause and in recognition of your efforts I'm going to have a go at building these boards by hand!  :o

My electronics experience consist of building Arduino boards and the like, I've never done surface mount soldering with paste and I am looking forward to this project.

I have placed an order for 3 of each board, at the special of $1 per set of 3 I thought I would get them all and have a go at this.
All going well I will end up with three sets of each board and with only 1 tank I will be happy with a 1 in 3 success rate (trying not to let the smoke out)
My biggest mission is going to be sourcing the components locally (Australia), I will try this before heading to Digi-Key as the shipping is ridiculous.
So I have a budget of $78AUD per TCB (I'm calling it a budget due to this is what HK sells them for so no point making them for more but I think I can halve this cost by doing it myself, not to mention that fact I like to build things not buy them)
I will post my progress but so far I have placed the order on the boards from Seed, and today I will start the component hunt!

One question i have is: using the hot plate do you sit the board right on it or use an old pan? I've seen both.

Cheers
 8)
Title: Re: Assembling Boards by Hand
Post by: pandknz on September 01, 2018, 03:08:52 AM
Hi again

I'm hoping that someone can point me in the direction of a component supplier that will have the following:

ERJ-PA3F1001V
ERJ-PA3F1002V
ERJ-PA3F1003V
C0603C103K3RACTU
C0603C104K3RACTU
JMK212BJ476MG-T - I have found a possible substitute but not sure if it is exactly the same - GRM21BR60J476ME15L
IRLML2502TRPBF

I have found that DgiKey, Mouser and RS Components are out of stock and back orders are in with 2019-2020 expected delivery  :-[

any help would be great

Title: Re: Assembling Boards by Hand
Post by: LukeZ on September 01, 2018, 01:44:24 PM
Hi Pand,

I would highly, highly recommend you just buy the TCB from Hobby King rather than try to assemble your own. I don't think I have ever assembled one myself for less cost than what they are selling them for. HK can buy the components in bulk but you will be buying them in small quantities at a far higher unit cost. The processor on the TCB is especially difficult to reflow correctly and I have ruined as many of them as I have made successfully even though I have a lot of experience with reflow soldering. I think my average cost for home-built, functional TCBs is probably somewhere north of $100 per board. That is 2-3 times what HK charges for a board made by a machine.

I can see why people would want to assemble their own Scout or sound card since those products are not yet available. They are also much easier to assemble having far fewer components. But there is no reason to assemble the TCB unless you really just like a challenge and don't mind blowing money for the fun of it.

Nevertheless, with regards to the bill of materials you listed:


As to your question about reflowing - I don't think it matters if you use a pan or not on the hot plate, i never do but I'm sure it would work. I usually just put a piece of aluminum foil on the hot plate surface but not for any thermal reasons, just to keep the hot plate clean. The flux in your solder paste will melt during reflow and trickle through the vias to the surface below, without the aluminum foil this will cause little stains on the surface of the plate which doesn't really matter but I might want to use my plate for cooking food sometime too.

The main thing to be careful with during reflow is to monitor the temperature and make sure you don't go over 200*C.
Title: Re: Assembling Boards by Hand
Post by: pandknz on September 01, 2018, 07:17:53 PM
Hi Luke

Thanks for the reply, I have purchased the TCB from Hobby King as I did the parts list and it came in at $85AUD and I got the boards made just because they were a $1 for 3 so why not, I can always just use them as borders when I apply the paste on the others (plus I got red boards so maybe I will make one later for fun, but yeah I do this as a hobby because I like to do this so cost is not a real factor within reason.

HK sell the TCB for $78AUD so its not that far off but a machine built one gives me a good base for testing the sound and scout boards which I will build.
The parts list is for the scout so thanks for confirming my list, cant believe the lead times on some of these products.


As soon as I get the boards I will post my progress, the Stug III is stripped down getting a Finnish Army paint scheme while I wait for the boards and full metal tracks wheels etc along with a few more detail parts

Cheers
Paul
 8)
Title: Re: Assembling Boards by Hand
Post by: johnnyvd on September 03, 2018, 02:01:43 AM
Hi Paul,

Great to see someone in action reflowing this boards. I'm very curious about your progression!
Please post some pictures and your findings while you progress!!

I'm still in the process of tuning my reflow oven and finding a way to organize the SMD components so i can build multiple boards at a time!

Good luck!

Cheers, John
Title: Re: Assembling Boards by Hand
Post by: pandknz on September 03, 2018, 05:06:39 AM
Hi John

cheers, I love new projects and this reflowing has my interest, especially the fact that I am forced to do it to get the most out of Open Panzer hardware.

I have the boards being made at Seeed and the stencils being made at OSH, all components are ordered through Digi-Key and I have ordered both a hotplate and a hot air gun/pencil to get this going. Not sure I will use an oven unless I get really good at this and a few people want to buy some boards, essentially I only need one of each.

I have also ordered 3 of those practice kits from ebay so I can get my technique right prior to unleashing on my first Scout and sound board.
But yes I will post pictures as I go, I'm away for about 10 days and when I return some of my parts might be waiting for me...hopefully  ;D

Paul
Title: Re: Assembling Boards by Hand
Post by: pandknz on September 20, 2018, 06:39:04 PM
New toys arrived today  ;D

Might start a new Topic just on my Board building experience

Sorry Luke, no Purple boards available through Seeed so I went Red to be different :)

(http://i206.photobucket.com/albums/bb21/pandknz/IMG_0681_zpsdsv110zx.jpg)
Title: Re: Assembling Boards by Hand
Post by: LukeZ on September 20, 2018, 07:59:16 PM
Looks good! Anyone interested, here is Paul's assembly thread (http://openpanzer.org/forum/index.php?topic=163).