I was missing the negative voltage, hopefully this may help if your also having issues

Having built the Smr4 board to the voltage test stage, the negative voltage showed as -2 and gradually rose to 0 v, and the tl1054 was running so hot I couldn’t touch it.

turns out I had capacitor C1 round the wrong way.

The one that is added at Step 3: power supply, Part 2: The (optional) 10uF tantalum cap (C1).

I didn’t realise that this was a polarised capacitor, as it just looks pretty much like a bigger Ceramic capacitors. Granted it is marked as polarised on the board so I should have been paying more attention, though think it may be useful if it is noted in the instructions that this is a polarised cap.

but once it was round the right way everything works well and the tl1054 didn’t die in the process.

Actually, I warn about this in the assembly instructions:


C1 is polarized. The positive lead is marked with a + and a band (see this picture)


Maybe its not red and big enough…

If I put this line in red, someone will make a mistake at another step and complain that “it was not written in red so I did not look at it carefully”. So maybe I should put all the assembly instructions in red and large font? But then it wouldn’t solve the problem because the line about C1 being polarized won’t stand out.

Read the assembly instructions, please!

indeed it is, my mistake, sorry don’t know how i over looked that