Beyerdynamic T51p repair
Disclaimer: the following article explains an unauthorized modification of a product. The manipulation explained in the article voids the warranty. Do not attempt to do the same operation, unless you know what you're doing.
I own a Beyerdynamic T51p headphones. I bought them in 2017, and a few months after its warranty expired, it started to experience a common problem for this model: the right driver would work only when the wire was put in a specific position. A few months later, it simply stopped working. In fact, the headphones use a very thin cable, and it seems that the cable broke.
I haven't used the headphones for a while, but recently, I finally contacted Beyerdynamic in order to know how much would it cost to repair the headphones. From a company specialized in rather expensive products, the experience when it comes to servicing their products is rather disappointing. It looks like they hate being contacted about the problems with their products, so they made the user experience as miserable as possible. For instance, you have to fill a form (which, among others, includes mandatory fields that I can't fill, as well as stuff in German), and then you have to do it again in an Excel file they ask you to download, fill, and upload. Either they have never heard of the fact that a script can generate the Excel file automatically, or they really want to make their customers' lives miserable.
Then it got worse. I was contacted by some company with an unclear affiliation to Beyerdynamic, and was told to send my request to an email address ending by “orange.fr,” Orange being a French ISP (so essentially this someone is unable for some reason to pay Google $12 per year to get a domain name!) The only reason why the person would contact me just to ask to contact someone else (instead of forwarding the original request, like any person would do) is to make me feel miserable one more time. I'm thankful for that.
I contacted the other person, who answered that I can always send him my headphones, but he would give a price estimate only after he sees the headphones (not sure what he expected to see, as my description of the problem was clear enough). He specified, however, that a minimum of €30 would be asked, which essentially means, as I understand it, that if I send him the headphones, and then I don't accept his estimate (which could possibly exceed the cost of the new headphones), he would then send it back without repairing it, but would still request €30 to be paid.
I therefore decided to service the headphones myself. Not only was it without additional cost (as I already have the spare cables), but it also allowed me to do three things: use a better, more solid cable, have a longer one, and get rid of the Y split that I find particularly annoying.
The major issue is to remove the drivers. One forum discussion is specifically about that, and I got the very same problem the original poster had: the drivers wouldn't pop out no matter how long I tried. The hint was to use a screwdriver and to intentionally damage the side of the driver. This way, I could insert the screwdriver further in, and finally won. A funny thing is that I also (unintentionally) made a hole in the fabric, just like the author from the forum discussion:
I should have drilled a hole, like the forum thread suggested: actually, you can notice that this is just a piece of plastic, and there is nothing on the other side:
The warning about air venting doesn't seem to be valid here, as there are already holes in the casing anyway:
The inside of the headphones looks like this. I'm surprised to see how small are the drivers compared to the casing itself. I'm not sure whether this is because the drivers need some air space behind them, or this is all about the design of the product.
Originally, I was believing that the problem is not the cable, but the soldering. Testing it with a multimeter, it appeared that the soldering was all good, and it was the cable which caused problems. This made no difference for me, since I wanted to replace the cable anyway.
Soldering was actually quite challenging. Since the driver is a large magnet, it attracts the soldering iron. And if the iron touches its surface, well... the magnet burns.
As I said, I hated the original Y split design, so I decided to put a short two-wire cable which would go from the left casing to the right one. This is essentially what I have with my excellent Sony MDR-7506 monitor headphones. Sony's ones have the wire go inside the structure. Beyerdynamic ones have a narrow structure which wouldn't allow that, so instead I decided to put it this way:
Looks ugly, but works well.
Here's the assembled version:
The fixing of the cable going from the left to the right side: