It’d be easier to answer these questions if we knew the current requirements of the Midimuso. Someone should measure it.
I’d think 2A wall warts would supply enough for a case, but of course it depends on how many modules and what current they draw. Is there anything else in the case that might be drawing a lot?
That’s the thing. My top case is pretty simple I think:
I’m planning to measure the current draw of a few modules tonight. I’m not sure the best way to do that. Do I build a little stripboard with two eurorack box headers and separate the +12v rail so the multimeter can measure the amp draw between the two headers? I’m assuming the stripboard would be connected to the power supply and to the module.
What I did:
The resistors are 10R, so the current on each rail is 0.1x the voltage drop across the resistor.
(If there are 10R resistors on the rails in the module, you can just measure there and have no need for this apparatus.)
Nice. I have never measured this before so I want to clarify. On the back of the stripboard, I’m guessing you separated the strips under the resistors so the current has to flow through the resistors. Then, you use the multimeter to measure the voltage, not current, by touching the multimeter to the exposed pins. Do you use the red probe on the hot pins and the black probe to ground? I’m trying to understand which two sets of measurements to take to get the voltage drop.
Measure across the resistor: one lead on the side toward the power supply and one on the side toward the module. I put in three resistors to measure current on the +12V, -12V, and +5V rails. Ground doesn’t enter into it.
I put the pins in as an easier target than the resistor leads, though the latter would be easy enough if you were foresighted enough to mount the resistors using holes further apart. Probably the better way to do it.
I think I understand. Here’s what I made. I’m going to make dinner and then stream my progress as I start measuring modules.
Looks like you have resistors on ±12V and 0V. So you can measure current on the ground rail too. I chose not to do that but I think it’s okay. If it’s not someone probably will speak up.
That doesn’t strike me as a good idea – you want your 0 V to be 0 V.
Fixing now. Thanks for the heads up.
Anyway, if you wanted to measure GND current, you should have cut also the two other traces, because the three center traces are connected together in the PSU/bus board and in the modules.
I have build 4 VCO. Two of them seem to be working completely fine. I tuned them and they behave just the way one would expect. The third one sounds just like the other two everything functions quite perfectly but I just can not get above 3.4 V at the test point. The fourth one suffers from the same issue and is also really quiet. nether the octave switch nor the fine tune knob work. There is a signal at the square, ramp and triangle output but it is rather faint especially if compared to the other three VCOs. Any ideas what could have gone wrong. I am a total noob so sorry if there is an obvious mistake. Any help would be greatly appreciated as I really don’t know how to trouble shoot this circuit
Hi rhizomax , you have probably already done this but : look for solder bridges , resolder components , check component values , this is usually a good start . in that order is easiest to more time consuming to do , well for me .
What @devicex said is good advice. Also, give the wires on the switch a wiggle to ensure there isn’t a weak connection there.
If you have the correct 4.1V LM4040AIZ, try replacing R42 by a 1k resistor, it looks like the LM4040AIZ is overwhelmed by the excessive current provided by the 220R resistor.
I was just about to mention this. I think the BOM/etc should be updated to at least have a 1k resistor. I did find the 1k slightly warm, but much closer to the temperature of the other resistors.
@lookmumnocomputer there is growing evidence that R42 should be replaced by 1K (or more) as I sugested here:
thanks Antoine I will do this on the Bill of material I will add a link to this as there is no harm in increasing it. however its awfully strange as I have never experienced heat on R42. I’m wondering what component may vary or if we are using different watt rated resistors, I must be honest I have probably for all of the builds stuck to the same source of purchase for all components. I’m wondering why some are experiencing the heat from the current running through and others are not.
Now the question is, who’s going to tell Robin Vincent to get out his Solder Sucker? 
Honestly, during the build session when he said “R42, that’s 220” I exclaimed a “nooooooo!”
Same. I’ve been testing my system after replacing all of the 220Rs last night with 1k resistors. It’s been running for 70 minutes now with no wobble. I suspect that even if one of them still had a 220R and was connected to the same power bus as the others, they would all wobble. That said, I’m waiting another hour or two before I assume the wobble is fixed. 
