Voltages to high on SMR-4 power supply or: synth DIY guide for noobs

Hi! I finally started to build my Shruthi today, and I just finished assembling the power supply on the SMR-4 board.
I came to the stage where I have to test the board, but voltages turn out to be wrong:
ground is zero everywhere… so far so good
but positive is 6,8 instead of 5 and negative is -6,8 instead of 5
I double (triple) checked all the polarities and if the components where the right ones… so far I can’t find an error…
Now… either my tester is wrong (could be, it’s a bit of a piece of crap) or I have done something wrong during assembly which I don’t know of… the strange thing is that I get pretty strange values also when testing the output of the power supply. shows 12V while I set it to 9…
Any suggestions?
I’ll try to find another tester… just not so easy since it’s sunday… but maybe there is something else I could check.

ok… I’m a noob
the batteries were running out on my tester…
problem solved so far…

hey rumpelfilter, im just as stupid as you :wink:

new batteries in Mr.Voltcraft magically corrects all weird Voltage readings on the Shruthis - must be some kind of morphogenetic field

Honestly: what about compiling a “The ShruthiVersum™ Guide to SynthDIY for Noobs” FAQ with all those hints and tips and tricks?

fcd, yeah why not? it could also say: dude when everythings working, but no sound at all, why not start with inserting …some of the transistors? that was me yesterday, glad & stupid at the same time

My Physics teacher at School: “It works better with electricity.”

My personal all FilterBoard Favourite is: put that damn white stripe on the ELKOs exactly where it is on the pic. Dont think just compare. Twice!

Maybe wo could also start a “Too dumb to build a Shruthi” Yahoo Group or something…

great idea!
Here’s what my highlights of the day were:

  • soldered one transistor the wrong way around, and i was even convinced I hat put it the other way, then, since desoldering would probably burned the transistor out, I cut the legs above the pcb, thus rendering them too short to get back into the pcb and one leg totally broke off. So I had to attach 3 solid core wires to it to make some “new” legs. It works, but I was close to rendering the component unusable…
  • added an IC the wrong way… here also I was totally sure of doing it the right way…
  • When I was done soldering the machine strips that connect the control board to the filter I thought I had done it wrong thant the long leads were too long… so I removed it… just to notice that in fact it was right…lot of work for nothing.

despite it all the Shruthi works! can’t believe it!

congrats!
yep somehow i know this procedure… wrong… what… was actually right… doh (usually the last part you have)

Must have been a hell of a Party last night…

But yes, i managed to reverse a transistor, too. Ready for some desoldering tips?

  • Do not desolder at all. First think, then solder else socket™
  • Use a low power soldering Iron (15W or less) to prevent burning the board.
  • For 2 or 3 Pin Parts (Resistors, LEDs, Caps or Transistors etc…) you have a chance by heating one Leg and bending the part to the other side. Repeat with the opposite pin to prevent overheating.
  • For parts with more pins use a socket :wink: If you didnt: get a new part, cut the pins and desolder the wires one at a time. Use a socket next time.
  • If there is Solder left in the hole (it shurely will) you can use fancy things like vaccum sucking tralala etc. Or go the LowTech way, get a needle from a Syringe , heat the hole and push the neddle thru. The solder wont stick on the stainless steel needle.
  • By all Means be gentle to your board, as gentle as you are to your grilfriend. This is not an Aircraft Carrier!

Trust me, i know what i’m talking about: