Sennheiser MKH 416

Hi folks,
I've recently acquired a broken MKH 416 P48 - I believe it's an early model - it seems to differ from the current version. The capsule is a KS15 (not the current KS16) but the capsule itself looks in good condition.

I just about know the theory of RF condenser mics but I've never worked on one.

The previous owner had some distortion problems (possibly related to dampness) but he also decided to replace some of the capacitors - you can see all the scorched areas on the pcb. His soldering skills also leave a bit to be desired - there appear to be some accidental solder bridges (see the arrows). I haven't tested them for continuity but they don't look good.

Also the tantalums seem to be 'grazed' on the top - I'm not sure if this just from sliding the cover off.

I can't find a schematic anywhere - the latest schematic on the web seems to be the 415, but that has fewer transistors and seems to be very different. I don't know if the guy even used the correct caps or inserted them correctly.

I think this is a long shot but:
- does anyone have a schematic?
- does anyone have a similar mic and can take pics of the back of the pcb, so I can tell more easily where the bad solder bridges are - some of the joints are really close together.

I think the first job will be cleaning the board and remaking any joints that look suspect. Any other advice or tips gratefully received.

pm'ed

First, huge thanks to bruno2000 for the help and information he supplied.

This is an update to help anyone else who may find it useful in the future.

I've undone most of the damage that the previous owner inflicted on the mic. I ended up removing all the capacitors that looked like they had been changed - it was impossible to read/check the values of the components in-situ because they're so tightly packed. The pcb traces lift really easily, so be careful - I managed to do quite a bit of damage  :-[ I used 30 gauge Kynar to make repairs.

I've made a recapping guide (attached) for anyone who may find it useful. Hope it helps someone.

My mic is now almost working - there's one final problem, but it's now producing sound so I'm nearly there...

Hi.
I have a sennheiser mkh 416 with a low plops noises. I need the schematics too.
Thank you

https://groupdiy.com/index.php?topic=45159.0

Has anyone ever cleaner the capsules in these?
Or know how to go about it.
I've read it can be done..

I have one with no low end and another that starts popping and rumbling after a few hours of being on.

Recently been trying out lots of different shotguns and keep coming back to the 416's.
Not surprised they're so ubiquitous. 

mrclunk said:

Has anyone ever cleaner the capsules in these?
Or know how to go about it.
I've read it can be done..

I have one with no low end and another that starts popping and rumbling after a few hours of being on.

Click to expand...

What you're describing makes sense for a standard Hi-Z condenser capsule, but these are low-Z and aren't supposed to suffer from those effects. I'd look at electronics first. 

thanks, that makes sense.
Going to fiddle later in the week. At least i have some working ones to compare.