WIP: Archibald (needs some debugging work)

[EBK]

I'm most of the way through building an Archibald, and I really like how meaty this build looks. 

Although a vent over the tube probably isn't really necessary, I couldn't help myself:

That cutout took many hours of drilling, cutting, grinding, filing, filling, trimming, and sanding.  I don't think I would try that again.     The dark gray is JB Weld to fill in gouges and the like from my Dremel.  It will be hidden under paint eventually.

I am, unfortunately, having trouble getting it working.  I have an apparent short between the 6.3V test point and ground.  I'm thinking/hoping it is due to a bad regulator, but I haven't pulled that part off the board yet.  The tube is a TAD ECC83WA.  I hope it works.

[dawson]

Looking like that, I would argue that the vent over the tube absolutely is necessary!

I hope you get it going soon.

[harryklippton]

Id say the cutout was worth it. That looks tight

[Bio77]

It's unanimous, that cutout rules!    What color is this going to be?

[EBK]

What color is this going to be?

I'm not 100% sure.
The plan for now is black with white lettering.  I'm not sure whether anything more colorful will work itself into the design.  It might end up with rainbows. I will let it evolve in whatever way it wants to go.

[EBK]

An observation from my initial debugging:

On a LM317 regulator, the heatsink tab is electrically connected to the output pin. 

I bolted my regulator and heatsink to the PCB, which only has a thin solder mask insulating the hole from the ground pour.

Well, my metal hardware ended up scratching the solder mask and shorting the LM317's output to the ground pour.

This is consistent with my earlier observation of an apparent short between the regulator test point and ground.

So, if you are planning to build an Archibald, do not use metal hardware to secure the regulator to the board!

You can see some of the exposed ground pour around the hole here:

[EBK]

Good news!

I installed a new regulator and kept it and its heatsink up off the board (the bolt no longer goes through the board), so it won't short out.


And....  Success!
Here it is, cheerfully glowing away, ready to make beautiful sounds!


That regulator gets seriously hot, by the way!  You can feel its heat through the face of the enclosure!  Hopefully, nothing will melt inside.

[benny_profane]

That cutout is amazing! Glad you got the shorting issue sorted. Can't wait to see the finished deal!

[alanp]

Phwoar.

As for the regulator, for that much heat I'd be tempted to run wires and bolt it to the enclosure itself with TO220 insulating stuff in between.

Good stuff!

[EBK]

Minor update: The enclosure is now painted black, which counts as progress.

I'm wrestling with a large image in Inkscape for the decal that will go over this, but I think I will win over the software this weekend, perhaps.

I don't know if I quite made this clear before, but the circuit is completely working now and sounds quite nice.

FYI,
I have noticed a couple build doc errors:
The shopping list should have two 1N914 diodes, and the EQ pot hole is out of alignment on the drill template.

[Bio77]

Looks awesome!   I can't get over how strait the lines are on the cut out.  It looks like you did it with a mill.

[EBK]

Thanks!  It looks a lot better with the paint covering my patches.  It has just enough tool marks left from my handwork to give it some character. I'm quite pleased with it myself.

[cooder]

Excellent, looks really great how it comes together!

[EBK]

I chose to add an image of the sun to this box, inspired by the enclosure size and how warm the regulator gets.


I'm still doing touch up work before I clear coat it.  This one would have been a great candidate for a UV print instead of a decal, but, like that cutout, I continue to do things the hard way.   

Excellent, looks really great how it comes together!

Thanks!  This is one of those designs where I just sort of started working before having a plan.  It can be more relaxing not trying to match an expectation.  Everything is a surprise, even to me.

[cooder]

Hot graphics, you gotta play 'Eruption' on it first thing when it comes together.