# My build progress

**URL:** <https://lookmumnocomputer.discourse.group/t/my-build-progress/345>\
**Category:** DIY STUFF\
**Created:** [March 1, 2020, 8:57pm UTC](https://lookmumnocomputer.discourse.group/t/my-build-progress/345 "2020-03-01T20:57:53Z")\
**Posts on this page:** 1\
**Showing post:** 5360

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**Author:** ![fatboab](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/fatboab/32/12330_2.png) [@fatboab](https://lookmumnocomputer.discourse.group/u/fatboab)\
**Post date:** [October 16, 2022, 3:27pm UTC](https://lookmumnocomputer.discourse.group/t/my-build-progress/345/5360 "2022-10-16T15:27:23Z")

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> [@analogoutput](#):
>
> Instructions say
> 
> > So we will replace our drain resistor with a BC548 transistor – which is just a standard general purpose NPN variant.
> 
> and a 2n3904 also is a standard general purpose NPN variant. I very much doubt the substitution is your problem.

Yeah, it wasn’t. I should really post this in the [litany of dumbassery thread](https://lookmumnocomputer.discourse.group/t/a-litany-of-dumbassery/526)… 🙄

I’m not really sure how anything made a noise and didn’t pop on previous steps, as I had the breadboard round the wrong way, in an effort to align it with the diagrams. All would have been fine if I’d also turned the power header round too, so I was sending -ve into +ve… 🤦

I have forgotten pretty much everything I learned last winter.

**Edit:** It also looks like I’ve blown at least the TL074, so have replaced both chips just to be sure.

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