KICKER DX250.1 Direct Short on Pos & Neg Power Wires? Why?

[zinda]

Used amp noticed the fuses were both blown (2x15A) so I used caution while I tested it. Put in 2 new fuses and hooked up the Battery + & - to the amp only, popped the main 60A fuse back into the distribution block and instantly blew the fuses. Removed it and took a closer look at it under my high powered inspection glass set up. Found no signs of any direct short any where. Removed board from heatsink, looked at all Fets and saw nothing except a very slight looking light blueish smoke residue near a screw that holds the rail onto the Fet and Temp sensor onto the heatsink. But this was such a slight looking residue that it really could be from anything since there is nothing there that has caused it. I moved onto looking for solder lap, long leads on solder joints, pieces of metal that may have fell in places that may cause a short across anything and finally looked at the actual copper lines on the board to see if there was any indication of hot spots or burning. Nothing again, the only thing I can say is there etching is really poor on this board, there were some strange spots where the coating looked like it wasn't covering the top layer correctly but still not the problem. I then checked the main diode hoping it was bad, not bad, left it out and tested it on a power supply that puts out less current than the fuses to see if I could get some readings on it. Problem is, the direct short will cause the power supply to pop it's breaker before I can get anything done. then it takes 30 seconds before it tries again. I was hoping on using a surface temp probe to see if I could see any temp rises in the components or spots on the board(s). I can't imagine what will cause this direct short without it being obvious. I really don't want to take every part out to test each one. Hoping that someone has fixed this type of problem and can point me to a more definite starting point since this amp isn't worth my time and effort if I can't do a quick fix. My next idea is to simply bypass the fuses and hook it back up to a 900CCA Optima and finding the problem instantly, although I know there is no guarantee that the problem will be exactly shown this way but it will give me a good starting point. Unless this board has more than 2 layers of copper lines on it and may be shorting out across the layers since I've noticed the poor etching, this could be happening if it has more layers, I doubt it has been engineered to that extent, after all it is just a Kicker Car Amp and they are not worried about the size of this device so much that it would even be worthwhile to produce it, but you never know. Any one ever see this happen before with no obvious problems?
One more thing, I have a pile of these Transistors from ERS marked ERS 153 D7 ERS stands for Exact Replacement Semiconductors, they are all individually packaged and have the same look as any P or N Mosfet Power Transistor does. A20 style if I'm remembering the form style correctly. Looked every place for a cross match but have no matches to get a data sheet for them. Could they be like IRF Z type?

[Khron]

Re: KICKER DX250.1 Direct Short on Pos & Neg Power Wires? Why?

Big hint: use paragraphs...

[midibob]

Re: KICKER DX250.1 Direct Short on Pos & Neg Power Wires? Why?

Zinda, if you're serious about trying to fix this then the last thing I would do is try to shove more power in to it!
All you will likely achieve is burning up the copper tracks and or board and making it fit for the bin.

Most likely suspects in these cases is FET failure, and probably more than one. The only sure fire and safe method, as you've already surmised, is to start isolating stuff until you remove all the shorted components and obviously check with a meter not with a PSU!

I can't help with the those semi's. One thing though, I wouldn't even think about using them unless you know what they are.

Good luck
Midibob

[Khron]

Re: KICKER DX250.1 Direct Short on Pos & Neg Power Wires? Why?

Zinda, do you at least have a DMM / multimeter?

[zinda]

Re: KICKER DX250.1 Direct Short on Pos & Neg Power Wires? Why?

I have a Fluke 87 and another 6 or so other meters also have a Sony Tektronix 326 scope. I just have never seen an amp that had this problem before with any obvious burnt fets. Every other amp that has problems has always had major unmistakable exploded fets and usually some burnt copper that leads up the them.

(paragraph)

As far as the box of packaged components I have, I have no plans on using them for anything until I can figure out what they are?! Was my question that hard to follow? Since I have scoured the web with no results I figured my best bet was to ask here. I've had these things for about a year now and just ran across them again while looking for other things.

They were purchased along with a pile of old car audio electronics parts like old under dash locking plates for removing the unit, some old Pioneer component parts for balancing amps and an old power converter. My guess it the 153 D7's are at least 25 years old since the other parts like the Pioneer stuff, was the same used on a system I had in my car back in 1983!

Back to the Kicker, it only has a few sets of fets on this board so I guess I could test them each but I have a feeling I'm just wasting more time and possibly making problems with remounting them on the already very poorly etched board. I'm sure that the copper will tear no matter how careful I am when I send them back through the holes, even if I drill them out first, I believe that the copper will tear loose no matter what.

[zinda]

Re: KICKER DX250.1 Direct Short on Pos & Neg Power Wires? Why?

I also forgot to thank Khron666 for the big hint! But I have already tried using paragraphs to fix boards before with no luck! LOL

[smason]

Re: KICKER DX250.1 Direct Short on Pos & Neg Power Wires? Why?

I also forgot to thank Khron666 for the big hint! But I have already tried using paragraphs to fix boards before with no luck! LOL

LOL.

I don't know much about car audio, if it was a radio transceiver I'd say look for a reverse polarity protection diode, they short and pop a fuse to protect against dummies hooking it up backwards. Somehow I doubt there's one that big in there if it's taking out a 60A fuse.

That said, shorts aren't usually that hard to find, especially ones that can take that much current even for a short time.

Some photos might help people smarter than me to help you.

[kc8adu]

Re: KICKER DX250.1 Direct Short on Pos & Neg Power Wires? Why?

almost certain to be shorted mosfets in the power supply.

[zinda]

Re: KICKER DX250.1 Direct Short on Pos & Neg Power Wires? Why?

Well thank you guys for leading in a direction that sounds realistic instead of just criticizing my sentence structure, I had no idea that the main idea of this forum was first and foremost having the emphasis based on my writing skills, I will have to warn you that I was a D to c+ student in English classes but was somehow able to get straight A's in Math and Science. Managing to graduate early with honors no less, but also no ambition to turn it into anything.

But anyway, I agree that the short should have been quite obvious, and I did check and removed the large Diode from the circuit thinking it was the most logical problem if there was no evidence of contact. As a stated it was not any part of the problem. I did however notice that when I attempted to replace it, I quickly saw how fragile this boards copper was, and do to this one easily removable part was instantly rethinking the mass removal of components for testing and opted to seek a wiser source of possible solutions that may limit the removing and lead to a more educated answer. So I came here, the only place on the entire net with people who actually do know what they are talking about.

Many times I've read posts that have solved my problems directly and had no need to bother anyone with silly questions that have been answered 100 times in other posts (if the time is taken to simply read them). So I already owe you all a big thank you for that alone.

It is starting to look more and more like I'm going to have to bite the bullet and hope for the best if I want to find the culprit. I have been thinking about upping the current slightly in increments while I am taking temp surface readings to see if I can unmask the first part of what may be causing this. This way I may be able to skip some of the unnecessary tests and retain the integrity of the copper. Of course there is no guarantee that the copper will not just burn away some place that has no bearing on the problem, simply thin enough to not handle the current. That is only 1 jumper wire that I will have to run, and maybe another, I have plenty of thin wire I can jumper across the board, I will post some pics so you can see the simplicity of the board and see the poorly etched areas.

It just seems easier to jumper wires on his board than to remove components, since the copper is so fragile it actually may be best. I know it's not the most common way to trouble-shoot a board or the most orthodox approach but, nothing ventured nothing gained. I just got a thought in my head and rather than removing the pieces I can just cut the copper test them 1 by 1 and solder jumper the cuts back together!! (I was just going to hit send when this came to me)!! The amp cost me less than $25 my time is worth that per hour, too many hours spent dicking around with it just to find that it's a piece of junk in the end is what I'm trying to avoid. I haven't heard much about them so I don't really know, I just thought that the direct short was going to be a breeze to fix. That was my first mistake.

[midibob]

Re: KICKER DX250.1 Direct Short on Pos & Neg Power Wires? Why?

In my experience it does usually come down to shorted FETs, sometimes visually blown apart sometimes not. There's not normally much else on the power rails that would cause such a drastic s/cct, main smoothing caps have been known to go short but that wouldn't be my first port of call. Be interested to see the photos though.


As for whether it's worth spending the time, I always go by if it's a piece of kit for me or a repair for someone else. For me my time is free so it's only parts that cost, if it's someone else's then as you say time is money and then you have to make a decision whether it's worth it or not.

Good luck
Midibob