I have recently purchased a Matrix 805 from a friend. Have been using it since the past 3 months and it performed very well. Since last morning, I am only getting the tweeter to work on one speaker. The mid-woofer is not working. Tried swapping to the other amp and problem is definitely with the speaker. The tweeter is working well. Opened the back panel and everything seems connected perfectly well at the binding posts as well as the driver side in the front. Please guide me if this is a Crossover problem and how I can diagnose it. Thank you
If there is nothing at all coming from it the first check is just to measure across the actual bass/mid driver terminal using ohms range on your meter. It should read low, I would guess something like 4 ohms give or take.
Do not press or move the speaker cone at this point as that may mask an intermittent issue.
Do not press or move the speaker cone at this point as that may mask an intermittent issue.
That sounds promising. As a further test if you connect the woofer directly to an amplifier then you should get sound.
What you need to do next is just check basic continuity from the woofer terminals to the cross over and then check that there is continuity through any coils in the crossover and that any low value resistors on the crossover are OK and not open. Crossovers are simple circuitry normally. It sounds like something is open circuit somewhere. Some crossovers actually have fuses and fusible resistor on them so look out for anything like that.
What you need to do next is just check basic continuity from the woofer terminals to the cross over and then check that there is continuity through any coils in the crossover and that any low value resistors on the crossover are OK and not open. Crossovers are simple circuitry normally. It sounds like something is open circuit somewhere. Some crossovers actually have fuses and fusible resistor on them so look out for anything like that.
There are 2 small crossover boards in the cabinet. One wires the tweeter and the other wires the woofer. Both the boards are individually glued to the inside of the cabinet with some hot glue. I guess I need to remove them to debug the continuity. How should I go about removing the board from the glue?
The LF (woofer) crossover just has two parts.
It should be easy to trace for continuity with an Ohmmeter.
Most likely you can measure without removing the board.
https://www.diyaudio.com/community/...-high-frequency-imbalance.287652/post-4632466
Hugo
It should be easy to trace for continuity with an Ohmmeter.
Most likely you can measure without removing the board.
https://www.diyaudio.com/community/...-high-frequency-imbalance.287652/post-4632466
Hugo
Based on the information shared here, you probably have a dry solder joint at the inductor. Do a continuity test between the woofer +ve and the speaker +ve: you should get continuity through the inductor, as it has very low DC resistance. Looks like you will have to remove the crossover board. You can do this by wedging a flat screwdriver or chisel under the PCB and prying it off, using gentle force, so as to not damage the board. After repair you can just reattach it with hot-melt glue.
Yes you are correct. I just opened the woofer to observe the Crossover. The inductor seems to have fallen off the board and hanging with the help of its wire. Seems like a dry solder there.
At first when i checked continuity from the positive woofer terminal of the speaker cabinet to the woofer positive lead connecting the woofer, there was no continuity. Then I slightly shook the inductor and the continuity is there. Fixed the woofer back and played. Again no sound from the woofer. Tapping the side of the cabinet, and the woofer plays. So I need to remove the Crossover board and check for dry solder and have it done. Attaching a picture of the loosened coil
At first when i checked continuity from the positive woofer terminal of the speaker cabinet to the woofer positive lead connecting the woofer, there was no continuity. Then I slightly shook the inductor and the continuity is there. Fixed the woofer back and played. Again no sound from the woofer. Tapping the side of the cabinet, and the woofer plays. So I need to remove the Crossover board and check for dry solder and have it done. Attaching a picture of the loosened coil
Was a great difficulty in removing the plastic spacers. Somehow manage to pull the board out. One end of the inductor coil had a dry solder joint due to the weight of the coil hanging by itself. The hot glue had given way so the coil was not affixed to the board as before. Carefully soldered the point and used hot glue to fix the coil assembly back onto the board and checked the continuity. All well. Connected the speaker. Everything played perfectly well now.
Thank you so much all of you for being so supportive . It's such a great thing to have all you pros around who help us unconditionally. Really appreciate
Thank you so much all of you for being so supportive . It's such a great thing to have all you pros around who help us unconditionally. Really appreciate