Epic fail (L4 kaputt)

[mybud]

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.



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.

 

[comradehoser]

Everything looks okay component and orientation-wise for the electrolytics, but I didn't check resistor values--except I can't see the 5817 stripe on either shot--could that be it?

If not, I'd doublecheck that the Traco module is a correctly compatible one. Maybe check for continuity between points of the circuit and/or jumper 9v in front of the 5817.

Are you measuring the output for 15V+/VA+ and 15V-/VA- from the daughterboard outs?

Waiiiittt a minute... Your daughterboard is wired upside-down, so are the wires still going to the right place on the main board? I would think not. Maybe that's not the issue, but I'm sure it could contribute to non-functionality.

 

[Nic]

Everything looks okay component and orientation-wise for the electrolytics, but I didn't check resistor values--except I can't see the 5817 stripe on either shot--could that be it?

If not, I'd doublecheck that the Traco module is a correctly compatible one. Maybe check for continuity between points of the circuit and/or jumper 9v in front of the 5817.

Are you measuring the output for 15V+/VA+ and 15V-/VA- from the daughterboard outs?

Waiiiittt a minute... Your daughterboard is wired upside-down, so are the wires still going to the right place on the main board? I would think not. Maybe that's not the issue, but I'm sure it could contribute to non-functionality.

I think those are ok, the board is just out and flipped.

 

[comradehoser]

I think those are ok, the board is just out and flipped.

Right, but then the daughterboard wires are referencing the wrong/opposite connections on the main board. Like -15 is going into +15. No? I mean, my spatial reasoning can't be that off, right?

I'm specifically looking at the pic in post 16 showing the full assembly and daughterboard connected upside down.

[edit: ah, I think I get it.]

 

[mybud]

I think those are ok, the board is just out and flipped.

That’s right and I did double-check that things were correctly wired.

 

[Feral Feline]

... I can't see the 5817 stripe on either shot--could that be it?
...

Stripe is there, and orients to the outer edge, not the middle;
diode's stripe is facing outer edge;
looks correct to me.

 

[comradehoser]

Well if you can see it on the 5817 (bottom pic) alright, I still can't. [edit: not bottom pic, that's the 4742; the 5817 is to the left of the rightmost switch. I don't see a stripe at all]

IC 4 is upside down?

 

[Feral Feline]

Well if you can see it on the 5817 (bottom pic) alright, I still can't. [edit: not bottom pic, that's the 4742; the 5817 is to the left of the rightmost switch. I don't see a stripe at all]

IC 4 is upside down?

Apple-polly-woggies!

Talk about epic fails... me trying to help. I know what a 1N5817 looks like yet I still got muddled with the (Zener?) pink outlines, yer talkin' bout the bit in green.



My L4 build-doc's representation of the footswitch daughterboard is bare minimum, and the only thing on the build-doc board diagram that says "D1" is actually labelled "RPD1" which is a pulldown resistor between IC4 and IC1.


Anyway, trying to help but I'm just gettin' in the way...

[cat, bowing profusely, backs away]

 

[comradehoser]

Apple-polly-woggies!

My fair Canadian brother,

It's totally all good. Sorry for being unclear, I don't know how to do the drawing on pictures thing.

I don't think I'm helping much either, but I am all in for helping my bud figure this out, and since I can't really speak to complex circuit analysis and diagnostic (Chuck D Bones I ain't) I tend to focus on the dumb stuff that I can understand first or have effed up personally.

Have done backwards 5817 and have done reversed ICs (it's why I use sockets now). Pretty sure I also did the wrong traco module at least once.

Go Oilers!