Coustic 400SE : powers on in protect

spooney · 3rd April 2011, 08:41 PM

I have this Coustic 400SE amp here that is powering up in protect. There are no obvioulsy blown/shorted outputs or power supply fets even. Checked every one of them with the meter and everything looks normal there. Upon applying remote turn on power to the amp it comes on with a red light indicating protection. If you leave it on for a few minutes it will randomly try to come out of protect for a second or two and then go right back into protect. Not really sure where to start with this one. It looks like the power supply driver IC is mounted on a little vertical board in the power supply area but it has been ground down so much you can't even see the clock mark.

Perry Babin · 3rd April 2011, 10:12 PM

Photo of the amp and driver board?

Perry Babin · 3rd April 2011, 10:17 PM

If you have the DVD, find the following file:
/repair_tutorial/miscellaneousstuff/coustic/coustic600se/cousticamplifierdriverboard.swf

spooney · 3rd April 2011, 10:17 PM

I will get those ASAP. The driver board is similar to the coustic amp in your tutorial but has a few differences.

spooney · 4th April 2011, 10:19 PM

Here are a couple pics:

spooney · 6th April 2011, 12:02 AM

After looking at the driver board in the tutorial I am thinking that these two driver boards are essentially the same however the one in this amp doesn't have as many smd caps in it. Next time I get a chance I am going to check those caps to see if they are shorted. In any of these that you have worked on Perry did they behave like this amp as in they would power on in protect and then try to power on every so often?

Perry Babin · 6th April 2011, 01:06 AM

Pull the rectifiers and see if the power supply will produce output. Measure the DC voltage on the gates of the power supply FETs.

spooney · 9th April 2011, 06:27 AM

Pulled the rectifiers and the amp powers on no problem. Power supply is functioning properly at this point. Put back in one set of rectifiers at a time(one in each supply) and narrowed the problem down to one channel. Not sure how but the first time through I missed a pair of shorted outputs(TIP35C). Clipped the TIP35c's out of the circuit and put the other set of rectifiers back in and now with all rectifiers in the amp it powers on and idles normally. So I have a channel I need to repair. Other than the outputs,drivers,and emitter resistors is there anything else in this particular amp that may need to be inspected/repaired/replaced?

Perry Babin · 9th April 2011, 06:46 AM

There is likely only one of the TIP35 and 36 shorted. Reinstall the two that are not shorted to see if it will produce clean audio. If it does, then you probably only need to replace the 4 output transistors.

spooney · 9th April 2011, 07:06 AM

I will give that a shot. Thanks Perry

3rd April 2011, 08:41 PM	#1
spooney diyAudio Member Join Date: Dec 2006	Coustic 400SE : powers on in protect I have this Coustic 400SE amp here that is powering up in protect. There are no obvioulsy blown/shorted outputs or power supply fets even. Checked every one of them with the meter and everything looks normal there. Upon applying remote turn on power to the amp it comes on with a red light indicating protection. If you leave it on for a few minutes it will randomly try to come out of protect for a second or two and then go right back into protect. Not really sure where to start with this one. It looks like the power supply driver IC is mounted on a little vertical board in the power supply area but it has been ground down so much you can't even see the clock mark.

3rd April 2011, 10:12 PM	#2
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Photo of the amp and driver board? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

3rd April 2011, 10:17 PM	#3
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	If you have the DVD, find the following file: /repair_tutorial/miscellaneousstuff/coustic/coustic600se/cousticamplifierdriverboard.swf __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

6th April 2011, 01:06 AM	#7
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Pull the rectifiers and see if the power supply will produce output. Measure the DC voltage on the gates of the power supply FETs. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

9th April 2011, 06:46 AM	#9
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	There is likely only one of the TIP35 and 36 shorted. Reinstall the two that are not shorted to see if it will produce clean audio. If it does, then you probably only need to replace the 4 output transistors. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

4th April 2011, 10:19 PM	#5
spooney diyAudio Member Join Date: Dec 2006	Here are a couple pics:

6th April 2011, 12:02 AM	#6
spooney diyAudio Member Join Date: Dec 2006	After looking at the driver board in the tutorial I am thinking that these two driver boards are essentially the same however the one in this amp doesn't have as many smd caps in it. Next time I get a chance I am going to check those caps to see if they are shorted. In any of these that you have worked on Perry did they behave like this amp as in they would power on in protect and then try to power on every so often?

9th April 2011, 06:27 AM	#8
spooney diyAudio Member Join Date: Dec 2006	Pulled the rectifiers and the amp powers on no problem. Power supply is functioning properly at this point. Put back in one set of rectifiers at a time(one in each supply) and narrowed the problem down to one channel. Not sure how but the first time through I missed a pair of shorted outputs(TIP35C). Clipped the TIP35c's out of the circuit and put the other set of rectifiers back in and now with all rectifiers in the amp it powers on and idles normally. So I have a channel I need to repair. Other than the outputs,drivers,and emitter resistors is there anything else in this particular amp that may need to be inspected/repaired/replaced?

9th April 2011, 07:06 AM	#10
spooney diyAudio Member Join Date: Dec 2006	I will give that a shot. Thanks Perry

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
old coustic 360 amp	fongman	Car Audio	41	22nd December 2009 01:38 AM
RTA, coustic?	jol50	Car Audio	3	6th May 2008 07:22 PM
Coustic 801	Tom7227	Car Audio	2	10th January 2007 06:54 AM
Coustic RTA 33	30bandgeek	Car Audio	2	9th July 2006 02:31 AM
Coustic amp460 phhht!	anatech	Car Audio	2	18th August 2005 12:49 AM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read