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Hey all. Merry Christmas.
Got a used Rode NT-2 with no signal on "cardioid" (setting) and a bit of noisy signal in "omni". A bit foolhardy, (probably) but I tried cleaning the capsule after opening up the headbasket and finding the two surfaces to be quite dirty, with lots of fibrous pieces of dust and tiny black speckles (not sure what these were, possibly from the foam windscreen?). (These seem to fit exactly the sort of dirt/debris described in this thread: )
http://music-electronics-forum.com/t21951/
In hindsight, I should have sprung for some 'proper' brushes, but I was feeling impatient (and cheap) so I used whatever I had (tissue paper, q-tips, cotton buds, a couple of calligraphy brushes, distilled water, and ethanol for disinfecting). The tissue paper I cut into strips and held the strips with some plastic tweezers to be a sort of brush which I worked quite gingerly to try to remove the dust fibers and black speckles. I also used the tissue to blot away liquid (I'd make little puddles to try to get the dust and dirt on the surface to dissolve into the liquid). I got most of the dust and black speckles off but when I finished (stopped), the center and edges weren't very pristine and clean looking because (due to what I had read) I was afraid of using too much liquid and having it seep into (or get sucked into) the back and sides of the diaphragm (there would be no way of getting it out since I don't have the know how or equipment to reassemble and re-tension the diaphragm). I actually managed to remove a bit of the gold sputtering on a side (a little 1mm or so hole plus tinier sliver shaped portions) which may (I say 'may' since things are so small and it's hard to see exactly what I'm doing without magnification) have been from using a (liquid-soaked) cotton bud and perhaps grinding a tiny piece of debris (black speckle) against the gold sputtering. (Yikes! But,) since I did however, remove 'major' pieces of fibers and black specks (also around the edges--I also used some sticky tape) I hoped it would be "good enough" and reassembled the mic.
After reassembly (which I had some difficulty and frustration with--the portion with the card/omni and LF cut/normal/pad switches mainly), I left it overnight and tried it the next day. And the next day... (to my semi-amazement) my amateur attempt at cleaning actually seems to have worked (small cheer). I've tried it over a couple of days so far, and it seems to be holding up (at least for the short term--knock on wood). Initially, I did detect a (momentary--not constant) low freq. noise, but I hoped that it was from residual moisture that hadn't evaporated from the capsule or switch-containing portion (which I cleaned with alcohol and a calligraphy brush after observing what appeared to be residual flux on the PCB in that section). I haven't noticed that noise reoccuring (so far at least), but one thing I experienced was the mic signal cutting out (then coming back) when getting very close to the capsule and breathing on it(I'm not sure if that was just simply getting too close and getting a temporary conductivity or from not cleaning the surfaces well enough but since the mic seemed to keep working consistently I'm hoping the former).
Overall impressions/thoughts:
-I wouldn't try this on something expensive (Neumann) without lots of practice.
-Cleaning could be worth attempting if you can get a non-working low-priced condenser for cheap and the major malfunction seems to be due to a dirty diaphragm (hiring someone to do it esp. somewhere labor is expensive would probably make it really uneconomical--i.e. it'd probably make more sense just to buy a new one w/warranty, etc., or even a "confirmed to be working" used mic.)
-Probably a really good idea to use magnification (strained the crap out of my eyes and in the final period, I tried taping a magnifying glass to a mic stand which made it easier but was still tiring for my eyes). (The dust particles aren't very easy to see with the naked eye. It's easier to see them under magnification or up close with a digicam.)
-Also probably a good idea to spend the money on some "proper" brushes. Should give more control in debris removal/washing and possibly less chance of damaging the surfaces. Another thing that occured to me is that a brush can be useful for washing an area of flux, so even if not used to clean a capsule it could be useful for something else (more uses = more reason to buy a tool).
-I got the mic w/out a case, foam winscreen, shock mount, etc. (i.e. no accesories). Also, when I got it, the headbasket smelled of perfume. So these factors, combined with (what seemed to be) particularly dirty diaphragms makes me think that this mic was not very well cared for (maybe a smoker was an owner--then someone else tried spraying the headbasket with perfume to obliterate the smell? Plus lot of dust = not stored in a case and possibly left out in the open for long periods with nothing over the headbasket?). I'm thinking more mics in a similar state are "out there" due to the availability of cheap condensers in the hands of recordists not really conscious or experienced in taking care of such mics, plus being used in "home studios" where the environment may not be very pristine compared to a professional studio (where as I understand, there can be a very conscious and deliberate effort to keep it dust free). So, if you can get non-working mics cheap, then these might be worth trying to resurrect (or at least practice cleaning on).
-As far as subjective impressions, I've read a lot of talk about "harsh China condensers" (this mic isn't but it does apparently have a Chinese made "K67-style" capsule reputedly responsible in part for excessively bright highs), but that wasn't particularly my impression (though there may be some bias from getting the mic to work again). I could sort of get that impression on (louder vocal) peaks (singing into it), but as far as being excruciatingly, unusably bright--I didn't get such an impression (but I don't have much experience with condenser mics and recording, so perhaps that will change). (My MXL603S SDC seemed to be in more of that "overly bright" orientation, subjectively speaking.)
Lastly there is a possibility (from what I've read) that I managed to get liquid where it shouldn't be (under/inside the diaphragm) though I did try to avoid it and it gets noisy or goes dead again sometime in future (but hopefully not). I'll report back if it does.
Got a used Rode NT-2 with no signal on "cardioid" (setting) and a bit of noisy signal in "omni". A bit foolhardy, (probably) but I tried cleaning the capsule after opening up the headbasket and finding the two surfaces to be quite dirty, with lots of fibrous pieces of dust and tiny black speckles (not sure what these were, possibly from the foam windscreen?). (These seem to fit exactly the sort of dirt/debris described in this thread: )
http://music-electronics-forum.com/t21951/
In hindsight, I should have sprung for some 'proper' brushes, but I was feeling impatient (and cheap) so I used whatever I had (tissue paper, q-tips, cotton buds, a couple of calligraphy brushes, distilled water, and ethanol for disinfecting). The tissue paper I cut into strips and held the strips with some plastic tweezers to be a sort of brush which I worked quite gingerly to try to remove the dust fibers and black speckles. I also used the tissue to blot away liquid (I'd make little puddles to try to get the dust and dirt on the surface to dissolve into the liquid). I got most of the dust and black speckles off but when I finished (stopped), the center and edges weren't very pristine and clean looking because (due to what I had read) I was afraid of using too much liquid and having it seep into (or get sucked into) the back and sides of the diaphragm (there would be no way of getting it out since I don't have the know how or equipment to reassemble and re-tension the diaphragm). I actually managed to remove a bit of the gold sputtering on a side (a little 1mm or so hole plus tinier sliver shaped portions) which may (I say 'may' since things are so small and it's hard to see exactly what I'm doing without magnification) have been from using a (liquid-soaked) cotton bud and perhaps grinding a tiny piece of debris (black speckle) against the gold sputtering. (Yikes! But,) since I did however, remove 'major' pieces of fibers and black specks (also around the edges--I also used some sticky tape) I hoped it would be "good enough" and reassembled the mic.
After reassembly (which I had some difficulty and frustration with--the portion with the card/omni and LF cut/normal/pad switches mainly), I left it overnight and tried it the next day. And the next day... (to my semi-amazement) my amateur attempt at cleaning actually seems to have worked (small cheer). I've tried it over a couple of days so far, and it seems to be holding up (at least for the short term--knock on wood). Initially, I did detect a (momentary--not constant) low freq. noise, but I hoped that it was from residual moisture that hadn't evaporated from the capsule or switch-containing portion (which I cleaned with alcohol and a calligraphy brush after observing what appeared to be residual flux on the PCB in that section). I haven't noticed that noise reoccuring (so far at least), but one thing I experienced was the mic signal cutting out (then coming back) when getting very close to the capsule and breathing on it(I'm not sure if that was just simply getting too close and getting a temporary conductivity or from not cleaning the surfaces well enough but since the mic seemed to keep working consistently I'm hoping the former).
Overall impressions/thoughts:
-I wouldn't try this on something expensive (Neumann) without lots of practice.
-Cleaning could be worth attempting if you can get a non-working low-priced condenser for cheap and the major malfunction seems to be due to a dirty diaphragm (hiring someone to do it esp. somewhere labor is expensive would probably make it really uneconomical--i.e. it'd probably make more sense just to buy a new one w/warranty, etc., or even a "confirmed to be working" used mic.)
-Probably a really good idea to use magnification (strained the crap out of my eyes and in the final period, I tried taping a magnifying glass to a mic stand which made it easier but was still tiring for my eyes). (The dust particles aren't very easy to see with the naked eye. It's easier to see them under magnification or up close with a digicam.)
-Also probably a good idea to spend the money on some "proper" brushes. Should give more control in debris removal/washing and possibly less chance of damaging the surfaces. Another thing that occured to me is that a brush can be useful for washing an area of flux, so even if not used to clean a capsule it could be useful for something else (more uses = more reason to buy a tool).
-I got the mic w/out a case, foam winscreen, shock mount, etc. (i.e. no accesories). Also, when I got it, the headbasket smelled of perfume. So these factors, combined with (what seemed to be) particularly dirty diaphragms makes me think that this mic was not very well cared for (maybe a smoker was an owner--then someone else tried spraying the headbasket with perfume to obliterate the smell? Plus lot of dust = not stored in a case and possibly left out in the open for long periods with nothing over the headbasket?). I'm thinking more mics in a similar state are "out there" due to the availability of cheap condensers in the hands of recordists not really conscious or experienced in taking care of such mics, plus being used in "home studios" where the environment may not be very pristine compared to a professional studio (where as I understand, there can be a very conscious and deliberate effort to keep it dust free). So, if you can get non-working mics cheap, then these might be worth trying to resurrect (or at least practice cleaning on).
-As far as subjective impressions, I've read a lot of talk about "harsh China condensers" (this mic isn't but it does apparently have a Chinese made "K67-style" capsule reputedly responsible in part for excessively bright highs), but that wasn't particularly my impression (though there may be some bias from getting the mic to work again). I could sort of get that impression on (louder vocal) peaks (singing into it), but as far as being excruciatingly, unusably bright--I didn't get such an impression (but I don't have much experience with condenser mics and recording, so perhaps that will change). (My MXL603S SDC seemed to be in more of that "overly bright" orientation, subjectively speaking.)
Lastly there is a possibility (from what I've read) that I managed to get liquid where it shouldn't be (under/inside the diaphragm) though I did try to avoid it and it gets noisy or goes dead again sometime in future (but hopefully not). I'll report back if it does.
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