First Shruthi-1 kit wont boot up

Discontinued DIY products Shruthi
#1

Hello!

I just completed my first Shruthi-1 kit but when I plugged in my wallwart (12v, 1200mA) nothing happened. No LEDs lit up and I do not have the LCD attached yet. I am fairly new to DIY electronics and I’m not sure how to go about troubleshooting. I will be picking up a multimeter tomorrow so any advice as to how to proceed would be much appreciated!

I’ve attached several pictures of my control and filter boards in case there are any obvious flaws in my component placement or soldering.

Thanks!

#2

I can’t really tell from the pictures, but did you bridge the two pads labelled “SW” ?
They are placed directly in front of the wall wart jack, and unless bridged nothing will happen :smiley:
(Im also assuming that you stacked the two boards while powering them up, and that you didn’t let any of the components on the bottom board touch the top board/vice versa)
=)

#3

Yes, I bridged the SW pads and it didn’t look like any components were touching.

Thanks!

#4

So what is the voltage at the SW bridge, after the diode and at the voltage regulator pins?

#5

Have you soldered the LEDs with the right polarity? You can try hooking it up to an amp and a MIDI keyboard to rule this out. At the exception of the regulators, is there any chip getting particularly hot? If the regulators temperature do not seem to change, have you checked the polarity of your wallwart?

For further testing, you will need the meter.

#6

This is how you can see the polarity of the LEDs, even after the legs has been cut.

#7

The LEDs are all correctly placed in terms of their polarity (thanks for the tip, I didn’t know that!). I don’t get any signal after connecting an amp and midi controller, though it did cancel out the hum of the amp when I plugged it in. I’m not really noticing any heat anywhere on the board and my wallwart shows the polarity as: – (o +

Heading to bed. I’ll be grabbing that multimeter tomorrow morning. Thanks for the help guys! G’night!

#8

Not related to your problem, but you should fully solder the tabs on the control board pots. So that the pots don’t move around (especially when pulling the knobs off).

#9

Do you get the correct voltages on the control board connector pins? there are pads for 5V and ground (0v), take a measurement there with a multimeter.

The only problem I’ve ever had soldering a Shruthi-1 was on the connector pins, it’s quite easy to produce a bad joint there.

#10

Placing the positive lead on the +5 out of the filter board and the negative lead on the GND reads as .6v

Is this the correct use of the multimeter? If so, then it would seem I am not supplying enough power to my control board?

#11

It might be that, or it might be that you swapped the two regulators.

#12

I did indeed swap the regulators! I guess it’s time to learn how to desolder, haha.

I will let you know how it goes. Thank you!

#13

Well… I managed to break the feet off both regulators while trying to desolder them.

Any way to recover or do I need to get new ones?

#14

It could be possible to solder them back even in this condition, but I notice that the regulator on the right has other traces of damage - at this point it’s better to start over with a new pair of regulators.

#15

I got my replacement parts today and everything is working perfectly!

Thank you all so much for the help!