Quote:
Originally Posted by Gilliland  Good point, Michael. I found this problem in my HRM10, and I was able to fix it myself, but I'm not sure I'd recommend anyone else try it unless they were quite willing to treat the mic as an experiment - the ribbon is quite fragile.
If you are going to try it yourself, be sure to completely remove the plate that holds the ribbon in place. Don't just loosen it - you WILL tear the ribbon. Once it's removed, you can use the tip of a jewelers screwdriver to gently lift the end of the ribbon from its place.
Now one end of the ribbon is loose, and you need to refasten it - with appropriate tension. There is no way to simply put it back and retighten the plate. So instead, take a QTip soaked with alcohol (pure isopropyl, not "rubbing alcohol") and wet the place where the ribbon needs to attach. Then, using the same QTip, place the end of the ribbon back in place. The wetness (surface tension) of the alcohol will be enough to hold the ribbon in place while you refasten the plate that will hold it permanantly.
Be careful to make sure that it is adjusted properly. The ribbon should be parallel to the magnet assembly all the way up and down, and it should sit nicely in the gap without touching either side. It should be tensioned loosely, but not loosely enough to let it fall out of the gap when the mic is horizontal. There should still be plenty of corrugation visible in the ribbon.
When you've got it right, be sure to store the mic vertically so you don't run into this problem again. |
Here's a picture of the ribbon sag problem below:
You can see the ribbon sagging out of the magnetic gap like a little footbridge. I'm stumped why I've seen a number of these mics - new, never out of the box, with this sagging ribbon problem. It is just as easy to get the ribbon tension right at the factory as it is to install a ribbon with sag. So I don't think this is a factory assembly problem.
This ribbon motor is from a mic that was returned to me for repair. The ribbon was perfect when it left my shop after modification but developed a sag sometime between leaving my shop and being put to use by the client ( who rightly complained of low output).
My latest theory is that the shipping parcel may have been dropped - even though the mass of the ribbon is small, the inertia aquired from the fall may have caused the center portion of the ribbon to continue to travel once it hit the floor. Any other ideas?
By the way, this problem can not be seen with the stock, three-layer headbasket in place. The headbasket has to be removed to inspect the ribbon tension.