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Old 03-26-2019, 02:13 AM   #1
Khron
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Join Date: Sep 2006
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Default Presonus Audiobox 1818VSL firmware dump

This is probably very much a "shot in the dark", but i have to try. Presonus support have been... well, let's just say, "less than helpful"

The bulk of the story:
Khron's Cave: #37 Presonus Audiobox 1818VSL teardown and troubleshooting (part 1)

I did some more poking around tonight, and there's absolutely squat re: clocks on the ADC/DAC chips (ie. MCLK, LRCK and BCLK / SCLK). Reasonably sure that's why the Vcom and the Filt+ voltages are almost-zero-but-not-quite on those CS4272's, but the /RST are high, so they're not being held in reset as such.

I reached out to a user on another forum, after discovering by total chance that he had an 1818VSL in use, but alas, doesn't have an SPI flash reader/programmer, nor can he gain access to one.

So i'd be reeeeeeeeeeeally grateful if, by some miracle, someone 'round here happened to have an 1818VSL and had the means and the kindness to desolder the firmware chip, read it out, and send me the contents (one way or another)

---
I also identified one of the two little chips right next to the CPU - the MSOP-10 packaged one is a CS2300-CP PLL / clock multiplier. https://statics.cirrus.com/pubs/proD...2300-CP_F3.pdf

I'm quite sure the SOT23-5 chip right next to the 13MHz quartz is a humble logic gate, which creates an oscillator using the quartz, feeding into the CS2300. That one's software-controlled though, and there's sod-all coming out of it, hence no clocks for the ADC/DAC chips. Haven't managed to figure out what the smaller 8-pin one is, though (marked "CNAA" or "CHAA", and "NZ17" on the second row), possibly some sort of buffer.
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Old 05-07-2019, 01:02 PM   #2
Khron
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Default Re: Presonus Audiobox 1818VSL firmware dump

Well, i ended up finding a working unit for a reasonable price locally (180eu) and, sure enough, "cloning" the firmware to my first unit brought it back to life instantly!

Or, well, as soon as a couple of my brainfarts cleared the air...

http://khronscave.blogspot.com/2019/...revisited.html
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Old 05-11-2019, 12:11 AM   #3
diif
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Default Re: Presonus Audiobox 1818VSL firmware dump

Nice work, I always enjoy reading about your new repairs.
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Old 05-11-2019, 01:45 AM   #4
Khron
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Default Re: Presonus Audiobox 1818VSL firmware dump

No thanks to Presonus' support department, though

As the old saying goes - if you want something done right, you gotta do it yourself
(Well, assuming you don't just wanna throw money at problems...)

I traded the revived unit with a friend, for a 1st gen Focusrite Scarlett 18i20. He's been testing the 1818VSL for the past couple of days, and all is well

Now... Anyone in the market for an(other) 1818VSL?
I can sweeten the deal by throwing in an M-Audio Profire 2626 to up the solution to 16in / 16out (analog)
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