Broken shruthi [solved]
  • Hi,
    I just finished mine and plugged it in. The only thing that happened was that the 8th led blinked but after two minutes it stopped and now it’s continiously lighting.
    There is neither a sound nor any kind of midi reaction.
    If there is a damage what I think, I suspect it’s the control board, but maybe there’s just a minor mistake…
    Thank you..

  • Have you done the voltage tests on the filter board?

    What is the voltage on the “+5V” pin on the control board?

    Is the ATMega644p correctly inserted?

  • The chip is correctly installed.
    Though it is said in the instruction that I should check it, I can’t do it because I do not have a multimeter. Sorry.
    Would it be possible to send it to you that you could check it for a payment? Or is it finally better to buy a new control board (without display) ? During the work I accidentally slipped of with a knife and i think i cut a trace and it took me some time to get into soldering again…. This is frustrating..

  • my suggestion would be: get a 10-euro/dollar multimeter and do the power test…

    if you’re into diy, you’ll need a multimeter.

    [edit: might we be feeding a troll here? first the enclosure thing, now this…]

  • I do not offer a repair service for kits.

  • where are you from FreddyB?

  • figure it out yourself! you will learn a lot and with the help of the community, you’ll be much better at this stuff in notime.
    first thing: get a cheap multimeter.

  • English is not my mothertongue (I’m from Germany) that’s why don’t know what you mean by “feeding a troll” – But I can imagine. I’m 17 years old, I still go to school and do not know much about diy synths but I’d love to get into it. So you could consider me as a raw recruit. Maybe you remember when you began with it and maybe you did a mistake and maybe you would have wished that there had been someone who had offered his help to you.
    Thanks to those who do it.

  • (again) where are you from FreddyB?
    Otherwise, you can get a cheap multimeter for 10$ / 10€. We can’t help you without a picture of your board, or without you taking some measurements.

    Your english is absolutely fine for a 17 years old guy whose english is not his mothertongue.

  • Nobody will really be able to help you unless you are able to provide some basic measurements about your device.

  • well, get a cheap meter, do the voltage test and post the results (and maybe a couple of pictures of your boards), and i’m sure you’re going to get lots of help here.

    and don’t worry about english not being your native language – im sure native speakers of english must be a tiny minority here. i’m certainly not one of them. :)

  • How did you fix the trace that you cut?

  • wow, that was 3 of us saying the same thing virtually simultaneously!

  • You are not the only one with such problems :) Born in Poland grow up in Germany(Berlin)!

  • no problem, freddy.

    you will get the shruthi working! the help here is really good. it is not that long ago, that i totally failed building my first shruthi. i could search for the thread for prove, but i am ashamed ;) i had to build another filterboard back then because i gave up on the first one.
    my first reflex was also to have someone do it for me, but now i am glad i did it myself and learned a lot on the road.
    the 2nd and 3nd shruthi (and a bunch of other stuff) worked just fine without problems on first power up
    ...and i even have an idea on how the whole thing works.

  • We all learn from our mistakes, some times we have to them again, and again, to learn. Good, and sufficient, tools are essential when building electronics as with every other work. Mutable Instrument instructions are among the best there is. If one does not follow them one can not expect to get help. Please get back to us when you have measured the voltages as described in the instructions and I’m sure you will get help as this community is a very helpful one.

  • @loaderbast I had the same problem with the IR3109 Board It was the first board that was not working at the first time!I’ve checked everything several times and I do not have guessed that the IR3109 could be broke :) Need an new chip.

  • @dalkiel: i don`t think it was a broken chip, just a whole lot of bad solder joints or broken trace and maybe a bad capacitor. (but thats unlikely) i had the cutoff and resonance both working, but not at the same time.. (so the chips should be ok) i still have it laying around and sometime when i am really bored i am goint to fix it and build myself a nice sidekick.

  • @Loderbast you could be right with the solder points(looks bad) and my the sidekick PCB is lying around here too.
    you gave me hope that the chip is not broke :)

  • I became a total master in desoldering after repeatedly soldering the wrong components in the wrong place :)
    Anyway, you might be surprised how easy the problem might be solved, once you check with a multimeter. The guide is quite well done in those regards (well also for everything else!)

  • Thanks to all your encouraging words! Amazing how fast and good the most people here seem to help each other!!!

    @MicMicMan: I live on the dutch border in western Germany. And I just ordered a basic multimeter. Thanks!
    @fleetway76: I used a loupe and took a closer look at it. Obviously the trace itself was not totally cut, but only the plasic(?) above; but it doesn’t look well.
    I took photographs but I overrated the resolution of our camera. There are 5 pictures:

    Before you look at them, let me describe the mistakes I did. Partly they are really stupid:
    After having build a contact microphone and some basic soldering practise I began, but my first soldering steps on the control board were – let me say – nervous ..(?). That’s why I supect it of being the problem.

    1) Control board:

    1. On the rearside I soldered the 8 220ohm resistors but two solder joints melted together. I used a desoldering pump but there was still a thin connection that’s why I utilized a thin electrical scalpell. Unfortunately I slid off and cut traces as a described above

    2. I accidentally inverted the two trimpots and the problem is that I couldn’t get the solder out of the holes that’w why I had to solder them as it can be seen on the pictures…

    3. All in all there are several – I would call them – overheated areas on the board and sometimes I can see copper (comp. pictures if possible)

    2) What I did wrong on the control board I wanted to to better on the filterboards. I honestly think that the soldering is much better on it. But I did two mistakes:

    1. I should not have allowed myself to be seduced by the (great!!!) instruction: On its pictures the 100uF caps were purple. So I soldered the purple ones into the power supply section but then I noticed that the purple ones are just 4,7 uF. I removed them, but as described above I wasn’t totally able to remove some ‘rest’ solder from the holes. So I had to shorten the new 100 uF caps and they’re soldered as it can be seen on the pictures. Nevertheless I’m pretty sure that this works. 2. And of course the accidentally inverted trimpot (see picture)

    All in all I’m relatively sure that it works.

    But I will use the multimeter according to the instruction to check some mistakes..

    Thanks to those who deal with my problem !!!
    If nobody has an idea I will buy a new control board.


  • A multimeter is a must have tool for this. Like everyone else, I screwed up in a big way a few times on both of the Shruthis I’ve built. You would think after doing one I would be wiser, but no such luck. Using the multimeter, you can check for continuity between circuits and you can check the value of resistors. I think these are fairly difficult kits for a beginner, but certainly not impossible if you have a reasonable soldering iron, some soldering skill, and the ability to PROPERLY AND THOROUGHLY FOLLOW DIRECTIONS. That last part has been my biggest problem. If you really have ruined one of the traces, and I did that too, you might be able to just use a jumper wire to go from one component to the next in the chain. You’ll need to have a close look at the circuit board diagrams on this site to figure out where to put the jumper. Get some desoldering braid too, it’s very handy.

  • regarding the solder in the holes: fcd72 heats the pads up and somehow puts a syringe through them, removing the old solder. but if you’re no (soldering) junkee and don’t have the pockets filled with needles you can also try another method (that works for me):
    reheat the pad and add a bunch of fresh solder, this will make it easier to remove because it still has the juice (insert Capacitor Fairy™ jokes here). when it’s really hot (but not too hot to avoid taking off the pad) just drop it on the desk. i’m doing this all the time and works quite well.

  • What is your soldering iron, freddyB?
    Could you take a picture of it?

  • Hi, the soldering iron is great although it was that cheap. It is definitly no problem …

  • Well, it’s not “that” great and it’s loaded with lead-free solder, which is not always ideal, especially since you’re a beginner.
    Anyway, i can spot a couple of solder joints that look pretty bad.

    So, you should first start removing all the ICs, and reheat a couple of solder joints in order to have them look perfect.
    Please look at the video tutorial Olivier has linked on the assembly instruction pages in order to know what a good solder joint looks like.
    Don’t overheat your pads, that’s useless and counter productive. If you can’t get a good looking joint on some pads, just let it cool down and work on other pads meanwhile.
    You might want to use the solder pump to start the most messy-looking joints from fresh. And you might need to add some bits of solder, so the current solder melts well. And clean as often as possible your iron tip with the sponge provided in your bundle. Don’t forget to put a tiny bit of solder on it before you clean it : that allows the tin too spread well on your iron tip, this way it’s going to work much better.

  • As for the ICs I always recommend socketing with good quality turned pin sockets if there is space enough. That way you don’t have the heat and re-heat the ICs in the case of bad joint or misplacement.

  • Which soldering iron would you guys recommend to me? Please keep in mind that I’m student… I will tell the results of my testing to you within the next days.
    Thank you!

  • As you are in Germany one of the cheaper Ersa ones seems like a good idea, you can get one second hand and I still buy spare parts for my 20 year old one. Otherwise the Hakko FX-888 seems to everyone’s darling but those are hard to find in Europe.

  • while a fancy soldering station is nice. i think it is not necessary for through-hole. i use a cheap noname 30W iron like yours. with the right solder tip, solder with lead and sometimes some type of extra lead (“lötfett” in german) i never had problems.
    i have no idea how my solder tips are called, but they are round and thin (but not to thin to allow enough heat to be transfered) i had a lot of trouble with the solder tips i got with a cheap C*nrad iron. then i asked the guy at my local electronic store which tips he uses and using them made everything 50% more easy.
    i recently found out, that i also find really thin solder is nice for me. (0,56mm)

  • lock on ebay for a Aoyue 936, got my for 18€

    700 x 525 - 42K
  • I’ve heard good things about the Aoyue 936, they use Hakko pens right?

  • I’m very satisfied and only 18 Bucks! Sry I have no idea what tips were used.

  • i didn`t know, there was a good soldering station that cheap.
    there is a used Aoyue 936 on german ebay which is ending today. i am thinking of buying it. please post here, if you also want to bid (i`ll let it go then) so that we don`t bid against each other.

  • I’m unsure what to say now … I really would like to bid on it. So unless you don’t need it maybe you would have the gentleness…. That would be awesome. If you need it I won’t bid.

  • no problem. you take it. i won`t bid on it

  • Hi,
    I have ‘positiv’ news. I checked the power supply and everthing is fine (always -4,99V or 4,99V). And the +5V solder joint on the control board shows 4,99V as well. Do you have an idea? Thank you so much!

  • that’s already a good news.
    what’s the behaviour of your control board now? led 8 continuously lit? Nothing happens when you press switches?

  • still the same phenomenon… do the chips have to be inserted if i check these things. when i tested in on monday with all the chips nothing was different from now without them. i didn’t do/solder anything in the meantime.

  • if you get the same voltage measurements with and without chips inserted, that’s potentially a good news. At least, that means that none of your chips is damaged to the point that one of them is just a shortcut. That doesn’t mean that your chips are still in good condition, though.

    First thing you need to do now, is to rework your bad looking solder joints, without chips inserted. Take your time, don’t hesitate to add solder and to use your pump, and don’t overheat. If a solder joint just doesn’t want to be cooperative, just fix some others and get back to it later. From the pictures you uploaded, we can definitely see that a lot of your solder joints are looking really bad, especially on the control board.

  • Hi,
    I found the time to rework the bad solder points but nothing has changed. Any ideas? Otherwise I will buy a new control board…

  • I bought a new control board and this solder station. I’s definiately 10x better with it that before and every solder joint looks as it has to be. But there is stil the same mistake. Only the 8th LED is shining…. Is it maybe a defect atmega chip? Otherwise it must be the filter board.

    Why do I have this mistake? Please help me …
    Thank you

  • If you suspect it is the ATMega644p, you can send it back to me and I’ll check it and if necessary send you a replacement.

    Which voltage do you have on the +5V pin of the control board? What do you see on the LCD?

  • Thanks for the answer!

    Yes I have 5v on the +5V pin. Furthermore I didn’t install the display yet, because as it is said in the description modifications are not easily possible anymore.

    I’ll be in Paris from monday to wednesday. Would it be possible then to come over to your place unless we don’t find a solution here?

  • I am sorry, I do not offer a repair service, nor do I have the capacity to get people to come to my workplace.

  • No I don’t want you to repair it. You said that I should send the chip to you. But if I’ll be there I could put the chip into an envelope and throw the chip into your letterbox for not spending unnecessary money on the postage. Thank you…

  • And … Would it be possible that there is a mistake on the filterboard? This all is somehow very strange … hopefully it will work soon.

  • The only thing the digital control board needs to run is a firm ground and +5V connection with the filterboard. And a solid +5V rail of course.

  • I’m optimistisc then. I’ll throw the envelope with chip plus 5€ for the postage to germany into your letterbox. Is that ok?

  • Just send the chip.

  • Hi,

    this my last try, after that we can hopefully delete this thread. Olivier graciously checked the chips on the digital board but they are ok. Since I have the identical mistake on my two digital boards I suspect that I do somethng generally wrong. My first question is, if somebody could attach a high resolution photograph of the digital board so that I can compare everything over and over again.

    If this won’t help: Is there someone who would have a look at the board. Of course I will pay for your efforts (even if you cannot find the mistake).
    It would be too sad to give up the project.

    Thank you so much !!!

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