Jonnie m
Member
Thanks MrClunk - how do I send a PM? cheers
Sennheiser MKH416T repair
- Thread starter The Documentary Sound Guy
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The Documentary Sound Guy
Active member
I made an attempt at opening up the capsule over the holidays. I was unsuccessful; the capsule is very tightly sealed, and all I succeeded in doing was deforming the capsule in the vise trying to keep it steady as I cranked on it. Here's what it looks like now:
So, next step: Try to find a replacement capsule on eBay. It should be a much easier repair if I can find a working capsule! I've made an offer on one, will post updates here whether I have success or not.
So, next step: Try to find a replacement capsule on eBay. It should be a much easier repair if I can find a working capsule! I've made an offer on one, will post updates here whether I have success or not.
thespecificocean
Member
Hi everyone! I am attempting to disassemble a MKH 435T and I'm really struggling. I've got the set screw removed as well as the snap ring inside of the XLR jack. However, the outer tube refuses to come off the body. What am I missing here?
The Documentary Sound Guy
Active member
I haven't worked with a 435T, so you might be better off starting your own thread for that one. If it's like the 416T, what you described should be enough, and I would be inclined to guess they parts have corroded together, but you'd be better off confirming by finding a schematic or repair manual.
The Documentary Sound Guy
Active member
Also, I wonder if you are pulling on the wrong part? Again, talking about the 416T, not the 435T, but my mic doesn't come apart *through* the XLR jack; there's no reason to remove the snap ring. Rather, there's a seam in the barrel, and that is where it separates. Again, you should look at a schematic to be sure.
Voyager10
Well-known member
If it's like the other MKH's the pin is all you need to remove, and the chassis will "just" slide out backwards from the tube, like this:
Obviously that's not working for you, so a couple of possibilities:
Obviously that's not working for you, so a couple of possibilities:
- There's a felt ring at the capsule end, to keep the chassis centred in the tube, which could have got itself stuck to the tube.
- The tube might be dented or slightly bent, and it's pinching the chassis which stops it moving.
thespecificocean
Member
Sorry for the late reply but it doesn't seem like I was getting notifications for this thread. Anyway, I did finally get it apart. I confirmed the procedure with Sennheiser, and they told me that very often it's the felt/plastic ring which solidifies or gets gummy to jam it up. That was indeed the case. What ended up working was clamping the XLR end to get more of a grip, and then simply pulling as hard as I could with a little bit of a turn. It eventually broke free, and I got it off. Whew!
As for the XLR connection, I believe that may have been part of the original issue since when I took out the snap ring, the portion of the connector with the pins essentially fell out with the wires attached. To that point, I now don't have a good reference for how it should be connected, and I don't fully understand the schematic as the pin numbers and the graphic don't match. Would you be able to take a photo of your 416T and/or advise how the connection should be made?
Many thanks!
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Voyager10
Well-known member
Happy to oblige, it'll be a day or two as I'm away at the moment.
It's best to be sure about the wiring, as getting pins 2 and 3 swapped will likely fry the transistors in the mic, on the T power ones.
It's best to be sure about the wiring, as getting pins 2 and 3 swapped will likely fry the transistors in the mic, on the T power ones.
Voyager10
Well-known member
Here's a pic:
XLR pin 1 connects to the case but is floating from pins 2 and 3. Red / XLR pin 2 is T-Power +ve, and Blue / XLR pin 3 is T-Power -ve.
The schematics (https://groupdiy.com/threads/sennheiser.45159/) are originally in German, so rt = Rot = Red, bl = Blau = Blue, sch = Schwarz = Black.
XLR pin 1 connects to the case but is floating from pins 2 and 3. Red / XLR pin 2 is T-Power +ve, and Blue / XLR pin 3 is T-Power -ve.
The schematics (https://groupdiy.com/threads/sennheiser.45159/) are originally in German, so rt = Rot = Red, bl = Blau = Blue, sch = Schwarz = Black.
thespecificocean
Member
Amazing! Thank you!
thespecificocean
Member
Well I got it all back together and did some simple checks but no dice. I'm unfortunately at my limit of technical knowledge so I'll have to look around for somewhere/someone to repair it if possible. I did order another mic that is reported to be working "sometimes" so looking into that one might give me some insights. Thanks for all the tips folks!
Voyager10
Well-known member
@thespecificocean (love the name) - do you have a digital multimeter and the ability to measure voltages on the board while it is powered? If so it is certainly worth checking a few DC voltages, which would give clues as to whether it is the capsule or something in the circuit. There are some posts earlier in this thread which give voltages, say if you need more information.
The service manuals are here: https://groupdiy.com/threads/sennheiser.45159/ which show the circuit layout.
The service manuals are here: https://groupdiy.com/threads/sennheiser.45159/ which show the circuit layout.
thespecificocean
Member
Haha thanks! Just now getting back to this as I wanted to wait... for another 435T to compare to (Plus I always like having pairs of mics for stereo use.) Anyway, someone else had a semi-functional mic on eBay so I picked it up for relatively cheap. Has a high noise floor and getting some thumps and crackles. I tried getting the capsule off or loosened to try making a better ground connection but haven't been able to budge it. Regardless, testing the voltage between the two test points shows 5mv and it responds to adjustments on L2.
Now onto the original non-working mic. Testing the same way leads to ~3mv but does not respond at all to L2 adjustments.
Does this mean my capsule is toast? Anything else to check at the moment?
Edit - I noticed that it looked like a connection from L2 was missing so I reconnected it. Now the test results in 0mv.
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Voyager10
Well-known member
You've posted two photos showing ~500mV and ~320mV - what were those? Those voltages are typical of a disconnected or broken capsule.
If you're seeing 0mV between A and B but it doesn't change when you adjust L2, that's suggesting a circuit problem (like the oscillator's not running or something is shorted). The first thing to check here is the voltage across C9 (i.e between the two rails which run down the sides of most of the PCB). Should be about 7V - if it's a lot higher, probably something is disconnected/open circuit. If it's lower, maybe there's a short.
If you're seeing 0mV between A and B but it doesn't change when you adjust L2, that's suggesting a circuit problem (like the oscillator's not running or something is shorted). The first thing to check here is the voltage across C9 (i.e between the two rails which run down the sides of most of the PCB). Should be about 7V - if it's a lot higher, probably something is disconnected/open circuit. If it's lower, maybe there's a short.
There are minor differences between the older 416T and 416P48 capsule and associated parts , the modern capsule is interchangeable with modification of the equalisation components on the older T powered version , there is a section in the MKH service documents about this ,
My guess is both mics perform substantially the same .
Below is the schematic for the convertor board Mr Clunk kindly sent me ,
I have the parts ,but didnt put it together yet ,
I might just assemble it into an XLR barrel jack rather than trying to fit the pcb into the mic body ,
My 416T is the XLR version .
My guess is both mics perform substantially the same .
Below is the schematic for the convertor board Mr Clunk kindly sent me ,
I have the parts ,but didnt put it together yet ,
I might just assemble it into an XLR barrel jack rather than trying to fit the pcb into the mic body ,
My 416T is the XLR version .
