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Messages - electricity440

#1
Amplifier Discussion / Re: Light Bulb Limiter
May 25, 2013, 04:42:17 PM
Quote from: Casey4s on March 24, 2011, 09:37:53 PM
This is just my second post here, but I couldn't help notice this thread.   I have used a ligt bulb limiter several times, it's a quick easy way to safely control startups and testing.

Here's my take on the limiter...



what software do u use to make that- i really need a good schematic designing program
#2
I have this nice amp that I got a few years ago. I was going to put it on a bicycle trailer with a 12v10ah battery and an inverter. The inverter is square though, so when I connected it the transformer made a very annoying buzzing sound. I was messing around and I put a 3.3uf 400v aerovox capacitor in series with the amp and that seemed to make the noise to go away- atleast for the first time. When I connected power again, the cap must have had a big charge and I heard a big BOOM, and the amp started drawing enough current for my wires hooking up to the battery to get very very hot. I then connected it to a light bulb limiter, and sure enough, the light turned on. The amp also had a burning component smell coming from it. Well the first thing I tested was the speaker. The speaker seemed to be fine. I then tested the transformer by disconnecting it from the power supply board. When I did that, the amp stopped drawing tremendous amounts of current and I realized there must be something wrong here. I also found this component on that board called TDA7293 (looks like the audio amp IC) which seemed to be the source of where the bad smell was coming from and was getting hot. When I removed that component, the current draw went back to normal and everything seemed OK. I ordered a new one from digi-key. Does what I am doing seem to be okay and is this how I should repair it? is there any other tests I should do? I really liked this amp and I want to be able to fix it!!!