Trade for a 'Broken' Kingslayer?

[PhiloB]

Guy listed a broken MB Kingslayer on CL.  Said he let a friend borrow it and it came back not working and the friend won't return his calls.  I'm relatively new to pedal building (9 builds under my belt).  Am I wrong in thinking this should be a doable fix?  I am supposing he either plugged in a  power supply with the wrong polarity or maybe plugged in an 18v power supply.  In either case, wouldn't it just be a matter of replacing a few components.  Or am I asking for it.

[Cortexturizer]

probably the zener has died. a friend did the exact sam thing to me, and replacing the zener fixed it.

[PhiloB]

He's interested in an Iron Bell clone I did.  I know there's no way to know for sure the issue but I wanted to make sure I wasn't missing something.  I guess worse case scenerio is having to replace a 14 pin IC with no socket, in which case I'd probably just harvest for hardware;). Wouldn't think it would be an issue with the IC though.
Bottom line is, I just don't quite have the self confidence in this hobby that I'd like just yet!

[raulduke]

I think trading a working pedal for a faulty pedal could very well be a bad deal on your end.

It could be the Zener that has blown, or the Voltage inverter, or it could also be a multitude of other things.

If its damaged, I would try a low ball offer ($25.00 for example) and see what gives.

A working pedals value is VERY different from a faulty pedals value.

[PhiloB]

Great point RaulDuke.  I've tried to sell this pedal since August with no luck. I like the pedal but I found that I don't have use for it. I've tried to sell it for as little as $30. That said you still make a great point.

[rullywowr]

Seeing as your pedal is worth about $30 to you...I think it would be a fair trade only if the Kingslayer is a fabbed board (not etched) and you like the enclosure art.  If the board is etched it is more prone to failure especially during rework/repair.

As mentioned, a good guess is that the Zener probably failed or an IC or two is shot.  No big deal in either case even if you dont have a desoldering iron.  If the IC is soldered directly to the board you can clip the pins off of it and then use your iron and a pair of small needlenose pliers to pull each leg out individually.

I have a very small pair of right angle needlenose pliers which I love for working with PCBs.  It's pretty much the only kind of pliers I use when working on PCBs and it rocks.  You may be able to find pliers like this in either a hardware store or a craft store (with the beading supplies).

[PhiloB]

Thanks rullywowr.  Thanks for the tip re: etched vs fabbed.  I'm taking my screwdriver to the meetup.  The enclosure is powder coated blue with no artwork.  I can repurpose it if it's a wash.  I'm going for.  That j's for the feedback guys!

[PhiloB]

I done did the deal.  All ICs were socketed.  Fabbed Sunking board.  Matte black powder coated enclosure.  Pretty solder joints.  Feel encouraged.  Now, how to trouble shoot this thing.  Dude said the led doesn't light up.  Probably won't get to it till this weekend.

[PhiloB]

[PhiloB]

Burn mark on the double sided tape under D3.

[Govmnt_Lacky]

I see the MAX1044 in there too 

Might want to replace that with the TC1044S or the ICL7660S.

If they plugged in a PS that was providing anything over 10.0000000000001VDC then that is probably a goner! 

[midwayfair]

If they plugged in a PS that was providing anything over 10.0000000000001VDC then that is probably a goner! 

This made me lol.

I really hate that chip.

[rullywowr]

So it's a Sunking...not a Kingslayer.     Nonetheless, looks pretty clean and I'd say you did well. 

D3 is the Zener and if there is a burn mark under it, it's a safe bet that it may be shea-doobied.  After that checks out I would begin checking for +18v (or around that) on the cathode of D5.  This will let you know if the CP is working.  Might as well just replace it with a TC1044SCPA. 

Also you may want to put a DMM on the foam itself and measure its resistance. Sometimes, foam can conduct electricity and cause shorts etc.

Fairly clean looking guts inside...cool deal.

[PhiloB]

So the Zener won't necessarily protect the IC?

[gjcamann]

If the zenier is dead, then it's not protecting the IC anymore - it did the best it could. It really only protects against  transients.