When I purchase and install a new tweeter, ... it appears there is something wrong. I replace it and it just immediately burns it out. I measure the impedance after replacing ... and it measures nothing. I watched your video on removing the module, I'm thinking there may be something bad with the module that is just burning out the tweeters upon powering up ... any initial thoughts? (have you seen this behavior and have any overall suggestions?)
The HF channel in the power amplifier is the most reliable section of the electronics. Assuming you don't hear any noise when it fails then the HF Amplifier chip (TDA7923) is the most likely culprit. If you do hear screeching and then it burns out it could still be caused by the TDA chip but I have seen a few with instability in the HF compressor circuit in the preamp board. My main job is design but I am happy to repair it. I have done hundreds of them.
You are exactly correct. You don't hear any noise. Seriously thank you so much for this response. I tried to look on digikey and mouser for this. Do you know where this chip can be purchased?
From memory it is component reference: U402 . Change the small electrolytics in the circuit, in the style of C405 and check R402. Soldering the part is a pain so make sure you buy the version with pre-bent legs. If the top-hat screw insulator is bad then change it and look out (serously) for pin holes in the insulation washer between the heat sink on all devices. I have so many failed repairs from 'specialists' that haven't noticed the devices are shorting to the 500 series heat sink. There are detailed repair videos for this amp on the channel.
Yes, I watched the entire video you made (ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-KERGqYwFEaE.html) ... It was extremely helpful (and really well done). I am trying to repair the exact speaker 300 series EON315. Do you know if there is a schematic available for this?
I had a funny experience there some 95% clones aftermarket diaphragm the only difference was the paper cover and frame was just abit less thicker on the screws so I had so tight it up way more but overall never get an aftermarket magnet they don’t have the same power I was testing what a surprise . The aftermarket everything is super chromed resistance was abit higher 4.5 instead of 3.7-4ohms oh the threads of the horn diameter was abit less thicker than the original nothing drastic but it works . And this Corp is a speaker repair company and it’s seems they bought this parts from China heh as I did buy another one fully different company with magnet and thy both has the exact same aftermarket diaphragm. Maybe a sound test w both on an rta would make me see and hear that there’s a difference
Yes, I noticed that the power delivery was slightly less but can easily be compensated by treble boost on the speaker or the equalizer. The DC resistance inst really such an issue as you might think. When you do the math it is the complex impedance at HF (audio) operating frequencies that is dominant. I have no doubt that the OEM parts are superior. When I get a moment I will put one on the rig and scan it then we can see the difference.
