Issue with Low Tide Mod build

[pcborpcp]

Hi there,

I got the Low Tide Modulator pcb along with some other projects. While I could finish the other effects just fine, I came across a problem with the Low Tide. I hope you can help me.

So the issue at hand is that the polarity protection diode (D3) gets fried whenever I power up the circuit.
After the first time, I removed all IC’s and transistors, because the board got really hot. But even without transistors and IC’s connected, the D3 gets fried immediately. I even tried to use a N4001 diode instead of the BAT48. The diode remains to get fried and it gets really hot.

I switched out the DC socket, double and triple checked the polarity of the wiring and the DC plug (center negative) and it’s all correct. I even let a friend look over the build, just to make sure I didn’t miss anything.

Do you have any idea, what the problem might be?
I would really appreciate your support on this.

Thanks

 

[bowanderror]

The latent heat of fusion for 60/40 solder is about 395 times the amount required to heat it by one degree. Transferring that much heat efficiently requires either a large tip or a high temperature delta.

Hell, it's impossible to set my own iron any lower than 662⁰f...cause I'm using an induction iron, and the temperatures are determined by selecting a tip rather than a setting on the screen. 350⁰C is as low as they go.

My mind must have been in the clouds when I was writing that, because I 100% mixed up my °C and °F...

My iron is in Celsius and is set to 350°C (662°F), and that's for 63/37 eutectic solder (with a lower MP of 183°C/361°F). Now that I re-read pcborpcp's comment, 572°F (300°C) is DEFINITELY too low, which makes sense given the lack of thermal damage to the board.

pcborpcp: I'd give 350°C/662°F a go, but feel free to bump it up/down to find a temperature that works for your given tip/solder/workpiece combo. The higher temp should make soldering & desoldering a breeze compared to what you had it set for before!

 

[pcborpcp]

If you read all that...uhhh....well, Imma level with you: part of how I learn is by restating what I've learned. That's why a lot of my posts tend to be fuckkkin essays. So thank you for bearing with me.

And second, if that's all gibberish, that's OK. Like I said, nobody should listen to me. Or at least, people should be entirely skeptical of what I have to say and I appreciate when folks pointing out when I get shit wrong. Even if my lizard brain gets all rage and murder for a couple mins.

See? We're all sane here.

No worries, your posts are insightful and I know I have a lot to learn. Can you recommend any book or online resource?

See? We're all sane here.

That's good to know. I feel like troubleshooting this project was messing with my head.

 

[pcborpcp]

My mind must have been in the clouds when I was writing that, because I 100% mixed up my °C and °F...

My iron is in Celsius and is set to 350°C (662°F), and that's for 63/37 eutectic solder (with a lower MP of 183°C/361°F). Now that I re-read pcborpcp's comment, 572°F (300°C) is DEFINITELY too low, which makes sense given the lack of thermal damage to the board.

pcborpcp: I'd give 350°C/662°F a go, but feel free to bump it up/down to find a temperature that works for your given tip/solder/workpiece combo. The higher temp should make soldering & desoldering a breeze compared to what you had it set for before!

Oh yeah, that works like a charm - especially for desoldering, thank you!

 

[pcborpcp]

So I've been looking at this thing for the last days and I think I've hit a brick wall with it. I've removed all the transistor sockets and then plugged in power to see what it's getting and my DMM reads -2.6V on the positive DC pad. Measuring the power supply shows 9V. So yeah, unless someone has another idea, I think I'm going to shelve this project for the time being. I just don't have the skills to solve this problem. But thanks to all members who tried to help me, I appreciate it and feel like I gathered some knowledge through you.

 

[Stickman393]

^-2.6v to ground, with the positive lead on 9v and the negative lead to ground?

Only way I could see that being the case is if you've got your ground going to the barrel of the power jack and the center going to +9v. But even with that, there would still likely be a short somewhere that's overloading the PSU.

It may be worthwhile to shelve it for a bit and come back when you have a little more knowledge. I've done that a couple times.

http://www.geofex.com/ -> good reading in there. Especially their beginners electronics article. I read that one a while back and it unlocked a lot for me.

 

[pcborpcp]

^-2.6v to ground, with the positive lead on 9v and the negative lead to ground?

Yeah, and polarity on the power supply is center negative.

It may be worthwhile to shelve it for a bit and come back when you have a little more knowledge. I've done that a couple times.

I agree. I need at least some time before I can look at it again with fresh eyes.

http://www.geofex.com/ -> good reading in there. Especially their beginners electronics article. I read that one a while back and it unlocked a lot for me.

Thanks! I'll dive into it.