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Old 03-29-2012, 12:08 PM   #1
ktulu909
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Exclamation Directed Audio 2400D powers on into protect.

Hey folks,I have a Directed Audio D2400 that has been in my car a little over a year.Its a high current car audio amp amp driving 2 Fosgate P3 10" at a 1ohm load,which it is stable at.

So basically the short version is that I got into my car last week and there was no bass.Worked the day before,never had it go into protect and then one day theres just nothing.

Voltage to the amp is adequate (been working professionally in car audio and security for 20 years,so I can promise its nothing with the install)Subs are metering properly and play just fine with my old amp.

I cracked it open and here are the pics.Looks like one cap is damaged,but ill let you experts chime in and let me know what you think.
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Old 03-29-2012, 12:21 PM   #2
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Default Re: Directed Audio 2400D powers on into protect.

What are the cap arting as printed on the body of those 5 caps and the 4 large caps on the pictures. This amp uses DC-DC step up switching power supply to power the power amp section
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Old 03-29-2012, 12:27 PM   #3
ktulu909
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Default Re: Directed Audio 2400D powers on into protect.

The 5 caps are 25V 2200uf

The 4 large ones are 80V 3300uf
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Old 03-29-2012, 12:45 PM   #4
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Default Re: Directed Audio 2400D powers on into protect.

OK, those 5 caps are for the DC input from your car batteries, the 4 large one are for the DC-DC step up switching power supply, I belive this use dual voltages (Plus supply and Minus supply) for the for the power amp sections, that why I can see two TOROID transformer. It may have gone into protection mode if it senses short circuits in the power amp section. This chassis will not be easy to work on with a lot of transistors attached to the heatsink. I would expect to see about 45VDC on those 4 big caps if you can access it from the top of the board. This amp looks like Class D amplifiers.
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Old 03-30-2012, 08:40 AM   #5
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Default Re: Directed Audio 2400D powers on into protect.

The top (as pictured) 25V/2200uF cap looks physically damaged, I'd at least replace that. Otherwise this could be a real PITA to troubleshoot with it shutting down, but if I were stuck on Gilligan's Island or something and it was the last power amp on earth, I'd desolder and pull the last stage output transistor pairs then see if it stayed turned on, measuring for signal at their lead locations... suspecting a short in one of those.
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Old 03-30-2012, 09:52 AM   #6
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Default Re: Directed Audio 2400D powers on into protect.

Pulled it out of the heatsink and it has 67.2 volts on the large 4 caps.And of course now it isnt going into protect.So it appears this is going to be one of THOSE problems.I cant even replace the damaged cap because of the mountain of solder on the underside of the board.All I have is a 40/20 watt solder station.And yes,it is a ClassD amp.

Last edited by ktulu909; 03-30-2012 at 09:54 AM..
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Old 03-30-2012, 09:56 AM   #7
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Default Re: Directed Audio 2400D powers on into protect.

Quote:
Originally Posted by 999999999 View Post
The top (as pictured) 25V/2200uF cap looks physically damaged, I'd at least replace that. Otherwise this could be a real PITA to troubleshoot with it shutting down, but if I were stuck on Gilligan's Island or something and it was the last power amp on earth, I'd desolder and pull the last stage output transistor pairs then see if it stayed turned on, measuring for signal at their lead locations... suspecting a short in one of those.
Yea,I agree about the top cap,but it looks like it was probably installed that way.I agree that I should probably change it,but like i said,I have no idea how to unsolder it lol.
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Old 03-30-2012, 10:59 AM   #8
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Default Re: Directed Audio 2400D powers on into protect.

feed it a very low level audio signal (so as to not create much heat with it out) and see if it works. Might just be a bad solder joint you've temporarily reconnected by handling the board.
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Old 04-04-2012, 06:26 PM   #9
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Default Re: Directed Audio 2400D powers on into protect.

This is a plus and minus switching supply. These run about 60 to 80 volts (pulsed) then get rectified into the + 30 and - 30 voltages needed to run the audio section. This is where 80% of the problems are with this type of amp.

When most amps fail or shut down it will mostly be one of the mosfets in the switching power supply. In your case caps too.

the mosfets are easy to check on both sides with a meter as they are all in series on each side.

If you find one side shorted then you will need to pull each one until you find the shorted mosfet.

You can also check the two rectifier diodes (in the middle bottom of the picture). They will normally be ok.

Then go after the audio section last.

As said above you do not want to run this thing with the heat sinks off it will fry quickly even at low volume.

You can bench run this amp with a 20 amp power supply. (use an inline fuse) Stuff happens!
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