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WIGGLING 'LITE' IN GUEST MODE

TSNM doubt: PCB/Schematics?
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page 1, 2  Next [all]
Author TSNM doubt: PCB/Schematics?
autodafe
I am building a Doboz TSNM and a small drop of solder fell on the pads for IC3

I removed it with a soldering wig, now I have a doubt. Are Pins 3-4 of the DAC (IC3) shorted together? I can't understand if on my PCB it's still a small residue of solder.
PCB rendering in the Build Instruction doesn't have it shorted, but looking at the schematics they look like they are indeed together?

Any hints before I make a mess???

My PCB:






PCB Rendering:






Schematics:

kashmir
They are connected together, the bridge on pcb should be there.
BugBrand
The pads ARE joined (just checked my PCB which is STILL awaiting assembly..)
autodafe
yeah I was thinking the same...the schematics speaks for itself, but I had this doubt after that drop spilled and I saw the PCB rendition, whic is probably not 100% accurate.
Thanks!
guestt
Does anyone know if the 33k 0.1% resistor 667-ERJ-PB3B3302V in the 4U build needs to be Anti-Surge?

It's the only thing I can see that is different from the other resistors but it's proving troublesome to source at the moment.

Cheers!
BugBrand
I think it is meant to be 36k - oh, wait, no, back to front - r27 & R28 should both be 33k - https://www.muffwiggler.com/forum/viewtopic.php?p=2781537#2781537

Anyways, sure they should just be whatever 0.1% 0603 size - dunno what Anti-surge really means, not sure it is important here & would think thin-film might be better.
guestt
Oh thank you smile

But now I am really confused, on the BOM I have downloaded from Doboz last week:

R27 is 1k

R28 is 4.7k

The resistor I was enquiring about was R14 - which makes sense in the link you posted as there was mistake with this one on the BOM that has now been corrected.

I was puzzling over the anti-surge quality, it's not something have seen before so wanted to check with someone.

I have plenty of 1% resistors in this size/value I just didn't want to place them, find out that it's a problem and have other things blow up because of a surge hehe grin

Finally, in other weirdness - I searched for tsnm and only this thread came up, but the thread you linked to clearly has tsnm in the title too, is search broken again?
BugBrand
TSNM search generates a fair bit??

Look at the schematic - you want precision resistors for the 33k

I think I've gathered all the parts but still haven't had time to start building, so I haven't got much of a handle on what is what other than based on the schematic. I followed the BOM only to some extent, changing versions where appropriate (hopefully sensible choices!)
guestt
I am obviously doing something wrong:



Yes, thank you, I got the precision bit, I am literally only enquiring abut the anti-surge property, nothing else smile

I have built a few of these now, all worked first time, even with part substitutions, but this is slightly different because it's the 4U version, very similar but with some little differences here and there!
BugBrand
As I say, I believe the anti-surge parameter is of no relevance and you should look for thin-film for precision resistors.

Oh, wait, I'm probably confusing everything! Didn't realise there was a separate/different schematic for the 4U - confusing/weird.
guestt
Yeah - at first glance anyone would be forgiven for thinking they were identical, in fact I nearly ordered the 3U Mouser cart for the extra bits and pieces without checking, but caught myself, thought no, that's just stupid and lazy, so did the usual line by line check and they are not the same wink
pathein
this thread has some info on the 4u diy ones,

https://www.muffwiggler.com/forum/viewtopic.php?t=190795

quite a number of the passive parts are still available via digikey instead of mouser which has some parts out of stock at the moment
guestt
pathein wrote:
this thread has some info on the 4u diy ones,

https://www.muffwiggler.com/forum/viewtopic.php?t=190795

quite a number of the passive parts are still available via digikey instead of mouser which has some parts out of stock at the moment


Thank you thumbs up
airfrankenstein
Just purchased one of these. seems to be a clean build, but it's not putting out any gates or triggers. I'm using it in sequencer mode, can get it to play notes, adjust note length, slew etc, but neither gate nor trigger open optomix, elements, or tides. I've gone through the manual but have yet to understand what's wrong. Is there something I'm missing?
synthetek
Seemed to be a common problem with one of the diodes being installed backwards causing the gates not work. Any pics of the board?
airfrankenstein
Thanks,

I hope that's where the problem lies.
Won't be able to check until Monday as I'm currently on the road.
just took a photo of the diodes before leaving.
keninverse
airfrankenstein wrote:

just took a photo of the diodes before leaving.]


Gotta be something else. Diodes are place properly. Is the pressure working?
Check and make sure IC6 is placed and properly soldered since gate and trig share this IC. then work back from there which would be pin 5 and 6 of the teensy. Try reloading the firmware as well.
airfrankenstein
Yes pressure was working properly .
Must be my settings though I’d checked to make sure triggers were active in sequence edit mode.
keninverse
Hey Sorry! I mistyped...IC6 shares trig and gate. Edited my reply
airfrankenstein
keninverse wrote:
airfrankenstein wrote:

just took a photo of the diodes before leaving.]


Gotta be something else. Diodes are place properly. Is the pressure working?
Check and make sure IC6 is placed and properly soldered since gate and trig share this IC. then work back from there which would be pin 5 and 6 of the teensy. Try reloading the firmware as well.


IC6...
airfrankenstein
Sorry to keep on with the questions but i just can't figure out what's up. SO I'm posting a video that tries to explain the problem I'm having - basically that gates and triggers are always low.

woodster
If it's not the Diodes or IC orientations I'd have a close look at the Caps etc. Whilst the soldering looks OK, the placement of some bits in that pic look a bit suspect. C11,C12 and C18 for example look like one side is possibly not properly connecting to both pads. hard to tell from the pic though.
airfrankenstein
woodster wrote:
If it's not the Diodes or IC orientations I'd have a close look at the Caps etc. Whilst the soldering looks OK, the placement of some bits in that pic look a bit suspect. C11,C12 and C18 for example look like one side is possibly not properly connecting to both pads. hard to tell from the pic though.


Eagle eyes! I'm going to check the connectivity. I hope it's that.

edit : connectivity seems ok. I checked grounding of the jacks as well. Everything else works. zombie
OIP
from what i remember reading some build threads a lot of problems are just bad / unreliable MPR121 boards, and fixed by simply switching the board out or reflowing it. doesn't quite sound like that is the issue here but it's worth a look i think.

mine will very occasionally drop a key 'press' and i've always put it down to the MPR121 but it's rare enough that i haven't bothered fixing it.
airfrankenstein
keninverse wrote:
airfrankenstein wrote:

just took a photo of the diodes before leaving.]


Gotta be something else. Diodes are place properly. Is the pressure working?
Check and make sure IC6 is placed and properly soldered since gate and trig share this IC. then work back from there which would be pin 5 and 6 of the teensy. Try reloading the firmware as well.


Hi there, my diodes are correctly oriented but my voltage on gate and trig output is steady at 10.23 v !
I checked connectivity on the board, IC6 seems fine - unless its placed backwards....If that op amp is dead the only things affted would be gate and trig out correct ?
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