Doing some checks on the pins, i can’t seem to get a reading from the 7912 ground and other grounds on the board, could I just run a wire from the 9712 ground to some other ground? I might have wrecked the through hole.
with the 2000mA power supply, looks like @lookmumnocomputer uses a 2000mA one as well.
The 2000mA is good. You could wire the ground to that of the 7812.
Awesome! Cheers, I’ll give it a go thanks!
Yeah, if you’ve lost the ground, the 7912 doesnt have anything to regulate against. You can verify by checking for connectivity between GND (pin 1) and the output GND. A wire to the other regulator’s GND should work (note that the pinouts are different).
Done! Getting the right readings now.
You guys are amazing. After reflowing and spending 2 hours wondering why my dual VCA wasnt working I realised I hadn’t used my FC Microbus to test modules before…yup had mixed up the regulators. Good news, I didn’t mess up the VCA build 
I just noticed that I did buy (and solder) 16V 4700uf capacitors instead of 25V…
12V RMS should be ~34V peak to peak, so to ground this is ~17V right? This is too tight, right?
The rectifier diodes will shave off a bit, but a lightly loaded AC transformer will output more than 12 V AC, so yeah, this isn’t good.
(e.g. this one that I was looking at the other day for a project has a “No-load voltage factor” of 1.11, so would peak just under 19 V, ignoring the diode drop).
This is what can happen…
Oh, That looks bad!! Yeah, I need to wait until the correct caps arrive even if it’s hard!
fortunately just one dead cap. My supply was rated to high, and was actually even higher in reality.
This one really has me scratching my head…
I just finished building four micro buses, and all 4 of them are doing the same thing…
I plugged them in and none of the LEDs light. I took the multimeter, all the outputs are measuring the correct voltages, so that’s good.
Here’s what I dont get. I took a loose LED, and I can get it to light on all 3 spots, on all 4 boards , but I have to put the anode (long one) on the ROUND contact point, and the cathode (short one) on the SQUARE. contact point.
Am I missing something? Every kit I’ve ever done the square pad got the longer end. Or did I get a shipment of bazaro LEDs?
From https://frequencycentral.co.uk/wp-content/uploads/FC-Power-Visual-Build-Guide.pdf :
- Solder the 78L05 and 3 x 3mm LEDs. Short leg of LED goes into square pad.
And in KiCad, all the LED footprints have the square pad for the cathode.
Well that explains it. Is that common for LEDs?
I’m looking at my white face kit from frequency central; for the electronic capacitors the square pad is marked with a +, which is the long conductor on a cap
Yeah, and same in the FC Power, and same in the KiCad footprints, for polarized caps the square pad is +. Seems illogical but there it is.
Thank goodness I ran into this before I put together the deep thought kit I bought . That would have been a lot of LEDs to desolder
The flat side on the silkscreen also gives it away. That is always the cathode.
have a batch of 3mm leds that must have been made backwards the flat side is on the wrong side . it was driving me crazy trouble shooting until i tried a different led .
I’ve been going around looking at all my kits… Clearly I need to build more if I’m making a mistake like that.
And I’ve got to say, Sam’s kits have the best markings by a country mile. Everything has a little + or - , and the resistor values are printed next to, rather than under the component.
That stuff makes a huge difference for the casual hobbyist.
I’ve actually bought only one LMNC module so far, the Triple Splashback, and on that one the references and values are not next to the footprint, they’re under the component:
Maybe because the board’s more densely populated than some of the other modules? Whatever the reason, it made things harder.
