Category: electronics

Tonight I finished assembling x0xb0x #888, but on first power up no audio is heard. The sequencer runs and I know the VCO works, but beyond that I’m not sure where the problem lies. Time to dig through the schematic while sitting in front of it with a scope.

Fun.

(I just hope I don’t have a blown BA6110 like some folks have had…)

A few days back I released my x0xb0x artwork into Creative Commons, but I didn’t mention what it was that got me thinking about the artwork and its license, prompting me to do this. It turns out that James Irwin was wanting to print more copies of this artwork up to sell via his shop AbleIdeas. Wanting the art available for others I licensed the art as I did, giving him permission to print and sell copies, and he agreed to send me one piece.

I received this piece of x0xb0x art today, and I must say that it looks pretty good. The texture of the plastic on the top layer is a bit more matte than my original pieces from Maverick Label, but the print quality and the cutting looks great. Lining one of his pieces up with mine showed them to be practically identical. The adhesive backing is the slightly thicker 3M 468 MP, which is 5 mil as opposed to the 2 mil 467 MP I’d selected from Maverick. This will adhere better to rough surfaces, but supposedly doesn’t help with the bond on smooth surfaces. I’ve been told that this adhesive will change to the 467 MP in future runs.

Oh, and (possibly) best of all? The Thailand Post (ไปรษณีย์ไทย) envelope the artwork came in was exceedingly cute (front · back). It could have used some backing board to ensure the artwork didn’t get bent (as the slight wrinkles visible here on the backing paper allude to), but the plastic looked just fine. I’ve mentioned this to James and he’s made note of it.

So, if you’re wanting some of my artwork printed up for your x0xb0x and don’t want to order in quantity from Maverick Label, definitely check out AbleIdeas x0xb0x store.

In x0xb0x #888 building news, tonight I sanded down the front panel to remove the epoxy lettering, cut a hole in the rear panel for the power switch, fashioned an impromptu indoor painting area, then began painting the rear panel. Hopefully I’m only a few days away from applying this artwork and finishing off another x0xb0x. I do still have to order some knobs and pushbuttons from Digi-Key, but those are essentially only finishing touches. Those can be changed after the case is closed.

After sleeping in a bit, most of today was spent on the mainboard for x0xb0x #888. Everything went quite well, the board cleaned up great, and it’s ready to hook up in the case. I even made a particular point of soldering all sealed components before washing, then doing electro-mechanical parts afterward with no-clean flux. I haven’t always been this particular in the past, and having to occasionally avoid a switch or button while scrubbing the flux off was a hassle.

Tomorrow I’m hoping to start on painting the back panel, possibly adding a power switch, and assembling everything for its first full-system test and (hopefully) tuning. I’ve already confirmed functionality of the power supply and USB (which the FT232BM from yesterday handles), so that’s a good start.

Here’s two more photos from today’s work:

· Soldered connections for the tactile switches, showing the slight bit of residue from no-clean flux.
· Detail of the cleaned solder joints on the DAC, located between the mode and bank switches.

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Either I’ve become a bit better at soldering, or things like the FT232BM in the x0xb0x are easier than I recall. I’ve finished the IO board so it’s time to wash and test it, then move on to the main PCB.

Here’s an amusing (to me) photo of solder dust from below the brass pad in the iron stand. Note the black cable tie at the top for scale.

Oh, also, this assembly is once again reminding me of my very dislike for cornrowed (upended) resistors. They take 3x as long to fit as normal, flat ones. Also, when there are 50 of one value of resistor right next to each other, maybe resistor networks would be a good idea?

UPDATE: Here’s the same chip, with most of the flux removed. There is still a very small residual amount of non-water-soluble flux left, which was removed after this picture was taken.

The sorting of parts and confirming kit contents against the BOM is tedious. On the upside, this x0xb0x kit (#888) is not missing any parts and now that everything is sorted I can begin putting it together. That’ll be tomorrow or thursday’s task, and hopefully I’ll finish up this weekend.

This kit is slightly different from the past ones I’ve received, because it came with domed red LEDs like the ones I had to purchase separately in the past. I’ll have to order a red RUN button and some knurled black aluminum knobs from Digi-Key to match the last piece of custom artwork which it will be fitted with, but that shouldn’t be a big deal. I should probably put a power switch on this one as well.

I think I’ve found what I want to do for my next electronics project. Fitting with my usual idea of taking another OSS project and adding fit and finish (and hopefully accessibility) polish to it, I want to take Atari SDrive by C.P.U. and make a new PCB and enclosure for it, and possibly sell some of the PCBs.

I intend to make the following changes from the current design:

· SIO connector to the Atari. Option for DB15.
· SMT parts.
· Double-sided PCB with soldermask.
· Different enclosure design, possibly with different label / pushbutton / switch configuration.