MTX MTA 225 Repair - Page 4

Perry Babin · 4th March 2010, 02:13 AM

If you could measure the voltages accurately enough and double-check them, that will help show the connections between many of the components where you can't follow the traces. After you see which ones have the same voltage, remove power and confirm the connections between those points with your ohm meter.

It will be easier if you print a photo of the board as large as possible. Print it so that it's very light on the paper and write the voltage for each point directly on the photo.

l7runner · 8th March 2010, 10:39 PM

Perry,

I replaced the driver transistor in the Z1 and voila! we have power. I was quite happy needless to say. I was able to read AC voltage out of the speaker terminals when a signal source was connected. I will be able to properly test it out later in the week. Thanks soooo much. I wish I would have spotted that shorted transistor earlier, would have made things much easier.

Now with the MTX, I have the required rectifier parts and will install them tonight. However when I looked over your diagram you posted for me I was a bit confused. It seems as if you have some anodes leading to the cathode and vice-versa. Perhaps I just looked at it wrong but I feel the need to double check. Any reassurance would be appreciated. Obviously you are the expert not me

Thanks

Perry Babin · 8th March 2010, 10:44 PM

The two green lines?

Those points are tied together on the board.

l7runner · 9th March 2010, 12:13 AM

Quote:

Originally Posted by Perry Babin

The two green lines?

Those points are tied together on the board.

Very true...I was just trying to go by the markings on the board and rectifier and match them up.

I will install the components later tonight and see how it turns out.

Thanks

l7runner · 10th March 2010, 06:03 PM

Ok I replaced the rectifiers with the ones mentioned above...I had quite a time running jumper wires to the legs of the rectifier. I re-pasted up all the components touching the heatsink, and bolted the amp back together.

The red power light comes on, which I assume means it is working rather than in protect. (I cannot remember what the power light looked like when working). I hooked it up to a signal source (playing music) and got fluctuating AC voltage on the speaker leads. So the amp seems to be working. I will be able to test it more thoroughly later in the week.

Thanks again Perry.

4th March 2010, 02:13 AM	#31
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	If you could measure the voltages accurately enough and double-check them, that will help show the connections between many of the components where you can't follow the traces. After you see which ones have the same voltage, remove power and confirm the connections between those points with your ohm meter. It will be easier if you print a photo of the board as large as possible. Print it so that it's very light on the paper and write the voltage for each point directly on the photo. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

8th March 2010, 10:44 PM	#33
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	The two green lines? Those points are tied together on the board. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

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
MTX TA7801 repair	intensem1rider	Car Audio	149	9th August 2011 06:11 PM
old mtx mta 250 high current problem	caseking	Car Audio	2	28th November 2010 06:46 PM
MTX 6500D Repair	Rasputin713	Car Audio	1	2nd September 2009 04:26 AM
Help me repair my MTX 500D please!	hakentt	Car Audio	28	5th February 2008 07:36 PM
mtx thunder895 repair	bcodella	Car Audio	0	5th July 2007 09:39 PM

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


	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

8th March 2010, 10:39 PM	#32
l7runner diyAudio Member Join Date: Feb 2010	Perry, I replaced the driver transistor in the Z1 and voila! we have power. I was quite happy needless to say. I was able to read AC voltage out of the speaker terminals when a signal source was connected. I will be able to properly test it out later in the week. Thanks soooo much. I wish I would have spotted that shorted transistor earlier, would have made things much easier. Now with the MTX, I have the required rectifier parts and will install them tonight. However when I looked over your diagram you posted for me I was a bit confused. It seems as if you have some anodes leading to the cathode and vice-versa. Perhaps I just looked at it wrong but I feel the need to double check. Any reassurance would be appreciated. Obviously you are the expert not me Thanks

10th March 2010, 06:03 PM	#35
l7runner diyAudio Member Join Date: Feb 2010	Ok I replaced the rectifiers with the ones mentioned above...I had quite a time running jumper wires to the legs of the rectifier. I re-pasted up all the components touching the heatsink, and bolted the amp back together. The red power light comes on, which I assume means it is working rather than in protect. (I cannot remember what the power light looked like when working). I hooked it up to a signal source (playing music) and got fluctuating AC voltage on the speaker leads. So the amp seems to be working. I will be able to test it more thoroughly later in the week. Thanks again Perry.

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