So I was on a pretty long hiatus because of a lack of motivation but mostly a lack of energy. But now I’m back and making actual progress getting at least a single voice ready.
I had a few half finished modules from before that were just waiting on some parts, including a Safety Valve that just needed the valve and a DPDT switch, as I previously had only bought SPDTs.
So yesterday evening I put those in and assembled the complete module. When off it just passed on the sound as it was supposed to. But when on it was just silent. Only when putting my mixer’s gain and everything else at max could I hear the tiniest bit of sound. Tone and gain didn’t seem to do anything.
Well, it was late and I called it a night, problem for future me. This afternoon I fired up the forum thread to see if anybody else had a similar problem, before actually doing any troubleshooting (yes I know, I’m lazy ok!). I read about that 27r getting hot and thought, “Hey, I remember reading about that back when. What did I do to solve that? Double up some resistors? Buy a higher rated one?”
Nothing. I had done nothing with that thing.
I had wanted to buy a 0,6W resistor but hadn’t gotten around to it.
And what do you know, just yesterday I placed a pretty big Tayda order, an order that i had been adding to for days just to make sure I didn’t forget anything…
But fortunately I had also placed a BanzaiMusic order (for some reason their opamps are cheaper than Tayda, enough so to warrant the extra postage) and they do allow you to add stuff for no added processing fee.
Fast forward an hour and luckily I click on the confirmation email because apparently I ordered a 0,27 ohm. Didn’t even know they went that low…
My latest tayda order included some more 10p eurorack power box headers, but im really confused because the little triangle is on the other side than the ones I already have:
My turn to post here. I like soldering decoupling capacitors at the underside of stripboard to save space, but this time I had an oopsie… Took me a while to figure out why the module wasn’t working (but that also had to do something with a backwards placed capacitor, and a half soldered component…)
Was just about to ask for help on this forum, but as I was typing out all the things I had done to troubleshoot, I noticed I’d done something stupid making Erica Synths diy delay… Turns out I ordered the wrong part. Ordered an LM4040 (2,5v)… It should have been lm4040(10v). Hours of troubleshooting… Couldn’t wrap my head around it. Especially since everything worked except for the dry/wet knob.
Looking on the bright side. I have learned or at least brushed up on the workings of opamps. I was getting really weird voltage readings and isolated the part of the schematic where something was going wrong. I just didn’t think about the voltage regulator being wrong! I’d never used an lm4040, mostly 7805 or something like that. Where the voltage is in the name! I just assumed an lm4040 gave 10v. Oops. Now to order the correct part…
Found out the hard way that flux CAN be conductive when boards are not cleaned thoroughly and one is so stupid to apply flux to the top of the board (during de-soldering of a trimmer) and not cleaning of the top before soldering the new trimmer in…
So: flux was under the trimmer, resulting in 2 noisy Ysuynth Minimog filters. Applying Pot Cleaner to the trimmers helped a bit (for a few minutes). Then the noise was back. Close inspection showed that the pot cleaner blew away most of the flux from under the trimmer away from the contacts.
Yesterday I ran down the stairs with a bloody finger. My partner told me to lie down on the floor, because it looked like I was going to faint…
Apparently those aluminium stencils are sharp. I wanted to peel off the protective plastic and ran the edge of my finger along the sharp edge of the aluminium stencil.
So I cut my finger. In my mind I needed to go get stitches. It really felt like a deep cut. But to the amusement of my family I’m a softy when it comes to blood. I exagerated. It was just a small cut.
Just hot plate soldered 4 pcb’s. Apparently with 5 ic’s in the wrong direction… So I ordered a hot air soldering iron to be able to desolder all of them… That’s 20 smt ic’s. If only I was paying attention… I thought this wouldnt happen to me anymore. I thought I had done this enough to learn from my mistakes. Nope.
Edit: More stupid. I actually didn’t make a mistake… But now I got to figure out why all of a sudden when powering on the new module, all the power got drained. Specifically when sending a gate to the module. Faulty cable? Faulty power supply? I need a break before I do more stupid. Like impuls buying a hot air soldering gun because I’m panicking.
Could have seen this coming, that octave switch doesn’t really do what it’s supposed to do. 25k V-I converter in parallel with a 50k divider ladder, not what I’d call stable. Now drawing in a buffer for the next generation of pcbs is easy, but how am I going to futz this on the current prototype…
[edit 1] I’m thinking tiny piece of stripboard with the buffer on it, some wires and a dab of hot glue.
Thought I’d save some bucks by binning a whole bunch of resistors instead of buying the 0,1% precision I need for all these heros and sidekicks I’m about to build. Paying with my time and not my euros so to speak. Only to realize that my cheap but capable Owon multimeter only has 2 decimals, not enough to accurately measure resistance to 0,1%.
So last night, actually past my bed time, I catch myself browsing for a multimeter with higher resolution. Having actually put one in the shopping basket before realizing, I’m about to buy a multimeter 4 times as expensive as the one I already have that’s perfectly adequate for my use in all other aspects. Just to save maybe 15 bucks of precision resistors…
So I stopped myself to rethink this in the light of day.
Now, ofcourse a better multimeter could get a lot of use over the years and I might want to bin more components later, but I alread have one thats fine, just not for this one task. I could also use this money to buy a reflow station, or a hotplate, or a module tester?
Oh if only I could spend my money twice…
2 decimals (6000 counts I assume) is just enough to measure 0.1% on a 10k resistor though? Ie you’ll be able to differentiate between 10.00k and 10.01k.
Very true, but I think I also need 1k.
I’ll have to recheck the git page. But there you have it, even if I do need 1k, I could just buy the precision 1k and be done… good thing I waited till morning.
Also, I don’t quite understand how those counts work…
Counts is the number of individual values the meter will measure/display. 6000 counts means, set to 60k range, it’ll display values between 00.01k and 60.00k. Set to 6k range, it’ll do 0.001k to 6.000k. So you should be fine, even for 1k 0.1%.
6000 counts, 4 digits. The number of digits after the decimal place is not fixed. From mantissas of 6000 (e.g. 600Ω, 6k, 60k, etc.) to 9999 it displays 3 significant figures (621Ω, 6.21k, 62.1k etc.) and from 1000 to 5999 it displays 4 significant figures (471.3Ω, 4.713k, 47.13k, etc.). So precision is in a range from 1 part in 600 (0.17%) to 1 part in 5999 (0.017%); it’s 0.1% when the mantissa is 1000.
