madbeanpedals::forum

General => Open Discussion => Topic started by: Kunfuz on April 28, 2016, 09:30:25 AM

Title: Second fail ever
Post by: Kunfuz on April 28, 2016, 09:30:25 AM
(http://i1177.photobucket.com/albums/x347/kunfuz/6AD6AFC7-5EAE-450C-B43A-1C7504FFDFC4_zpsa0ok5zwh.jpg)

So this was supposed to be build #57.
My first proper minibuild, a rat/Runt from madbean.
All wired up and ready, I connected the power.
Sound in bypass, completely silent while on.

Took out my multimeter and measured voltages.
9V enters the diode, 0V goes past it.

Hmm, must be a dud, so Instead of switching it out I just solder in a jumper.
Still no sound and the LED isn't glowing.
I then inspect my wiring of the new to me, mini-DC-jack.
Reversed +/-, so that's why I got 0V out of the PROTECTION diode  ;D ;D

Of course I killed the metal can IC, all of the electros and more.
Started to replace electros, then got stuck with the third (C11).
Got mad at my own stupidity, and just cut the whole effing board out.

Now I'm waiting for a second Runt-pcb, and another shipment of components.
Always trust the diode folks
Title: Re: Second fail ever
Post by: EBRAddict on April 28, 2016, 11:00:48 AM
I'm surprised and not surprised it killed the IC.

FWIW I bought 10 DIP8 308 chips from a Chinese eBay seller, and while fake they all turned out pretty good on gain, bandwidth, noise and even the compensation cap worked properly.
Title: Re: Second fail ever
Post by: stringsthings on April 29, 2016, 09:50:48 AM
2 fails out of 57 builds is a pretty good record.  I've just went through a phase of debugging about 5 circuits.
After a while, debugging isn't so bad.  It's really the mental aspect that is challenging.  When you consider it just
a part of the building process, it gets rid of some of the frustration factor. 
Title: Re: Second fail ever
Post by: Frank_NH on April 29, 2016, 11:54:59 PM
When I have vero builds that don't work out, I harvest (i.e. desolder) as many components as I can (except resistors) and use them in future builds.  Lately, I've started using my breadboard more, which makes the harvesting phase particularly easy  ;D