No sound! Depressing innit? IC3 to blame

No sound here on one of my builds. Oh noes, I said to myself. I even started looking apprehensively at the oscilloscope, Before getting to that stage I decided to probe all the voltages on the SMR-4 board again. What![](? No +/5 VDC at IC3) Strange, is there a short somewhere? The 7805 got kinda hot because of my 12VDC bench supply.

OK, so all voltages looked fine before soldering all the components to the board… Did I mess up even though I was extra paranoid enough to actually measure all the resistors? Loosen the board from the enclosure bottom plate. Double-you-tee-eff! The IC3 socket was only soldered in the 4 corner pads. Small wonder, midnight soldering sessions should always be checked again the day after. Fix that, re-assemble. Now it makes the coolest little bleeps and blorps!

Moral of the story - it’s never complicated! Be methodical and triple-check your own work.

Ahah! It happened to me a few times before… I usually keep the most difficult pads (GND) for the end when soldering ICs. And sometimes, I forget them :confused:

I tend to do the GND Pads with a bigger (means for me 15W instead of 8W) Soldering iron, especialy the GND Pads at the Trimpot of the Digital Board seem to suck loads of heat, so with my standard fimsy SMT Iron its nearly for shure a bad soldering joint.

Note that the problem has been greatly reduced in the most recent boards due to the use of a hatched groundplane.

I was wondering about the hatched pattern. Good to know what it’s for…

a|x

I always tend to work with outdated Stuff :wink:

Ground solder joints are more difficult to solder because the ground plane, which has a large surface, sucks up all the heat. With a hatched pattern, it sucks up less heat - not that much, but it’s welcome! The only drawback of the hatched pattern is the slightly increased ground plane impedance (it’s not possible for the return current to take the “shortest path” - it will slalom through the grid) - not a big deal here.

With an 15W iron its no problem at all. The problem is more on my side using this tiny little 8W Pencil Iron. I cant even solder 05mm^2 Mic cables with it :wink:

With a standard 20W Iron everything is fine, so its me using the wrong tools rather than Oliviers PCB design…

:slight_smile:
i believe my iron has about 40W and i always have it at 410°C.
so i didn’t even notice a difference, never had problems with any ground soldering (with a crappy iron i had at the very beginning a few years ago, it was quite difficult i remember)
i just noticed the new structure the boards seemed to have.