Epic fail (L4 kaputt)

mybud

mybud

Well-known member
So after the L5 clean and L5 legacy builds, I was looking forward to building the L4 bass version. It's quite a bear of a build with some specialised parts, as below.

IMG_1821.jpeg

All seemed to be going according to plan but no dice when I fired it up. I had checked the voltages beforehand and they looked kind of off but I thought that this would come right in the wash.

Silly hubristic me. It didn't.

I haven't the chops (or the heart TBH) to try to troubleshoot this but it seems clear from the really silly voltages (0.678 on IC1 for starters) that I've somehow managed to bork the voltage converter. The rest is (a resounding) silence.

I'm trying to be philosophical and not yield to disappointment and self-blame for a change. This hobby is a learning curve after all.

This goes into the box of shame and I'll try again with a fresh board later, I think.

So the real question is how does the hive mind deal with abject failure if and when such occurs? I'd really like to hear from others on how they deal with this.

Disclaimer: this is not the complete assembly. The one I tested was fully populated.
 
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Is Q7 facing the right way?

I dread the silent pedal like we all do, but failures and repair work are the only time I really learn anything in this hobby. I try to look at it as an opportunity where I might be forced to look at the schematic in a meaningful way and learn something.

Honestly I don't even usually make it that far though. It's usually just that I put the wrong part in the wrong hole.
 
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I see a lot of missing ICs, resistors, wiring, switches and jacks. Could have something to do with the lack of signal hahahaha

If it's any consolation, my L4 works, but definitely developed issues--in the compressor section, I think. I'm also not looking forward to wading into those waters.

Sometimes, the big issues are easier to diagnose, though.

Print out the schematic, and just do the usual troubleshooting protocol. Check cables, amp, and bass first, then visual inspection with the ref des and attention to polar component orientation and solder bridging, then voltages, continuity, and audio probe.

You got this, my bud!

[edit: also since the voltage converter is on the footswitch daughterboard, maybe if you isolate the issues to that, Aion would be willing to send you just the daughterboard.]
 
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comradehoser said:
I see a lot of missing ICs, resistors, wiring, switches and jacks. Could have something to do with the lack of signal hahahaha

If it's any consolation, my L4 works, but definitely developed issues--in the compressor section, I think. I'm also not looking forward to wading into those waters.

Sometimes, the big issues are easier to diagnose, though.

Print out the schematic, and just do the usual troubleshooting protocol. Check cables, amp, and bass first, then visual inspection with the ref des and attention to polar component orientation and solder bridging, then voltages, continuity, and audio probe.

You got this, my bud!
Click to expand...
Yes of course you’re right but that’s not the stage that I tested. Did have the complete set of parts in place 😉

Thanks for the encouragement, my friend.
 
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#1 way to success:

mybud said:
... I'll try again...
Click to expand...


You will succeed.






Me, on the other iron, I just make like a Templar Knight and ...

monty-python-and-the-holy-grail-run-away.gif



... from whatever fiasco I've made, and ...

Yqrx.gif


... to creating an entirely new debacle.
 
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You can test if it's the power supply by measuring the voltage on +15 and -15 coming off the breakout boards.

It might be the first time someone points out a positive about Aion's breakout boards, but testing this one is one of them!
 
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also share photos of your boards - might be one of our eagle eyes might spot something.

Mine works and is the closest to an helix amp sim in solid state I've heard - big fat complex tone. Then I rebought a HX stomp and retired it
 
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Thanks to all who chimed in on my problem.

Here's an update as promised FWIW:

IMG_1825.jpeg

I've measured the voltages from the DC converter meanwhile. Tested with 500mA output from my pedalboard PSU.

This seems to be where they problem lies, since instead of the expected 15 and -15 volts, I'm getting fractional readings (0.678V and so on).

Seems that somehow I've blown the converter in testing it. 'Nobody's fault but mine,' as the song goes.

L4 PSU.png
Step 1: I'm going to see if Kevin (@aion) has any spare daughterboards to hand (simplest solution). He's by no means obliged to help but worth a try, I think.

Step 2: If not, I'm going to try to build a +-15V power supply to test the main board, which may or may not be functional. That will make the most of what's already done and in place. I did think of adapting one of my modular PSUs as a temporary kludge but these run on +-12V so probably not clever to try such a workaround.

Managing the offboard channel switching without said daughterboard is no doubt a complex challenge but maybe doable if I keep my head.

Step 3: Start the whole process with a fresh board. Least desirable option but at least I have a functional drilled enclosure to house the boards.

Fact is, accidents happen and you can't win 'em all. Thanks for bearing with my thinking aloud.
 
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Well, you could just go troubleshooting ham on the breakout board since it's so limited. I would do ALL the probes (except audio)

Can we get closeups on both sides?

My guess would be something polar that's flipped or off-spec --maybe even the Traco module--maybe a trace or short issue, particularly in the section feeding from 9V into the Traco. So, C45/46?

I also cracked an inductor installing it.

[edit: I have faith we can find and fix the error without redoing anything]
 
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