I killed my SMR-4

I had a working smr-4 filter board until I tried to swap the already in place standard 1u caps with fancy ones. It was a real pain to desolder and putting the replacements in and after this struggle I now have no sound left at all.

I tried swapping all the ic’s from my second (working) smr-4 and that didn’t help, so its not the ic’s I figure. Are there any components close to the 1u caps that I might have damaged/burned. I had to the soldering iron on that location quite a lot before i had the caps in place.

With one of the caps I had an issue that one pin didn’t want to connect properly because of residue. Is it possible that the sound completely disappears if one cap isn’t connected properly? Or is it more likely that I broke something else, for example the transistors?

Try to identify at which point the signal chain is broken.

A badly solder cap will break the signal chain. The filter caps are 1nF, not 1uF

Yes they are 1nf sorry for the confusion. I thought because they’re so huge they can’t be 1/100 of the capacity of the tiny ones :wink:

I’m going to give it a try with a multimeter, because I don’t have a scope…

You need to probe the circuit with a bit of wire connected to an audio jack. Multimeters only measure averages or RMS levels of signals.

I made myself a nice pumpkin soup and when I came back all my troubles were gone! I don’t know that the hell happened but it’s magic.

Thanks for your help. It’ll come in useful when I start figuring out why my Roland board isn’t giving me any output…