DIY Sennheiser MKH416 P48 REPAIR

[LoganSound]

My trusty (about 15 year old) 416 went scratchy today, intermittently crackling with multiple cables. I had opened it once before so I was curious to take a look and found that one of the two resistors on the input stage had badly corroded (see pic). Sharing this for others, perhaps for my own memory, and to take the comments of those wiser than me: fire away.

Notes on opening:

-Remove the C-clip from inside the XLR jack with a pair of needle nose tweezers or tiny screwdrivers, while this actually wasn't necessary in this case it's worth noting.

-Turn the flathead set screw on the exterior and remove it

-Remove the top outer case, the XLR jack assembly does not separate from this microphone without desoldering the two leads between the main board and XLR jack so do not attempt to pull the jacket of the XLR off until these leads are desoldered (or just cut if you are adding new resistors)

-And pull out the Phillips head set screw on the underside next to previous set screw hole, now it is safe to pull the XLR jack and sheath away from the body

 

I was able to shift this daughterboard slightly without removing entirely to slide new resistors into place:

The old resistor was Brown Black Black Gold: 10 ohms +/-5%

After an unsuccessful Google to try to find a matching replacement I opted to try a 10ohm I had around, 5 bands: Brown Black Black Gold Brown: 10ohms +/-1%

While conceptually I was fairly confident this would work some threads made me doubt whether it would sound as good, initial results are positive but I may opt to match the remaining resistor at a later date.

Resoldered, cleaned some remaining corrosion with DeOxit and an old toothbrush and re-assembled good as new?

[Philip Perkins]

So....how does it sound?

[LoganSound]

13 hours ago, Philip Perkins said:

So....how does it sound?

I just shot a B-A-B test! I didn't nail the proximity but sounds fine to me!

[Patrick Farrell]

A couple of thoughts:

From my recollection, removing the XLR section shouldn't be necessary to get to the board. I guess that could be revision specific though.

Replacing a 10 ohm resistor with a tighter tolerance 10 ohm resistor will not have an audible difference in any schematic.

[Matthew Steel]

I'm not used to seeing resistors with green colored bodies.  Are you sure the original wasn't a 10uH inductor?

 

If you are concerned enough to open it back up you could measure the remaining original with an ohmmeter.  I would expect a 10uH inductor to have a DC resistance that is close to 0, definitely less than 10 ohms.  If measuring in-circuit make sure other components don't skew the measurement.

[Matthew Steel]

FWIW I went looking for a schematic and found this video that says those are inductors (chokes) not ressitors:

 

 

 

[LoganSound]

4 hours ago, Matthew Steel said:

says those are inductors (chokes) not ressitors

Wow! Great find! I will order those right away!

[LoganSound]

Well I replaced both inductors and while it works, there is some intermittent scratchiness so I am going ahead and replace the plug body part in entirety, $136 with shipping:

https://sennprospares.co.uk/shop/MKH416-and-MKH816-XLR3M-plug-body-complete-p432263720

Will update after I replace, will be interested to see if this has any update to the fit of the XLR C-ring that has always made a little click when moved in mine.

[LoganSound]

Wanted to follow up after a few months of use post-repair: highly advise anyone who has an issue in the "XLR plug body" simply buy the replacement, it was super simple' two solder points and the mic sounds great again without worrying if I made a mistake that will cost me later.