State Variable VCF 12dB and a big bang

jovius · Joined: Apr 22, 2009 Posts: 8 Location: uk

I've just finished a State Variable VCF 12dB , plugged it in and one of the electro caps ( C13) went pop (BANG) i (kick my self) managed to swap the +15 and ground , (kick my self again ) just wondering what components people think i mite of knackered ?

thanks
jo

inlifeindeath · Joined: Apr 02, 2010 Posts: 316 Location: Albuquerque, NM

possibly none. try replacing the supply filtering components, hook up power correctly Very Happy

and see what happens. When I mess up I usually assume the worst and then as long as I catch it quick, it's usually not too bad.

jovius · Joined: Apr 22, 2009 Posts: 8 Location: uk

i've replaced the electro caps , and r29 had blown replaced that and c2 c3 ,
when i power it up r29 gets hot , i've taken all the chips out and it still gets hot to hot to touch,, i've checked the board for dry joints and bridges but cant find any and checked to see it the were any shorts on the chip sockets which the isn't, checked the wiring all fine dont know where to go from here ?

Paradigm X · Posted: Tue Dec 06, 2011 3:42 am Post subject:

Im no expert, but i was told recently with a similar problem;

Remove all chips and measure resistance from V+ to ground, and V- to ground, and V+ to V-. If very low, 0-5 ohms, you have a short somewhere you need to find. If you havent got that problem, then it lies elsewhere, and is likely to be incorrect component placement.

Hope thats helpful.

Mongo1 · Joined: Aug 11, 2011 Posts: 411 Location: Raleigh NC

Belated advice - ALWAYS power up the board without the chips inserted first. Check the power pins to make sure power and ground are proper on each chip every time. You can save an awful lot of money and time that way.

I can also tell you that even if the chips appear to be working now, they may have suffered damage. You may want to replace the cheap stuff just to save yourself headaches down the road.

Gary