What type of microphone is a midland 22-150, dynamic or condenser? Does it require a 48V dummy load?

Question edited for clarity, full 'make model (what it is)'.
Question moved to a better category.

Definitely worth repairing. You can also get repair kits.

https://www.google.com/search?q=Sennheiser+MD+46+repair

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Just about any mic will do. I have used a Midland, Motorola, GE, Radio Shack and other microphones on these radio's. The mic element must be dynamic. Condenser microphones would require you to slightly modify the mic input circuit of the KLM to provide 5 to 10VDC through a 4K7 resistor to provide bias for the condenser element. It's easy to do if you have the skills to do it.

hard to say without more info. you probably know this , but as a condenser mic it requires 48v phantom power to operate. Does the pre-amp/mixer you are plugging it into provide that (there will be a button on it marked 48v)? If not, that is the problem.

Depending on the type of element; dynamic or condenser, you won't likely be able to repair this yourself. Both are delicate and use very small dimensions. The condenser type are most likely to survive a drop but the dynamic type is easier to damage and if it is an E815S, it's dynamic.

Phantom Power (or an internal battery) is needed to operate 'Condenser' type microphones.
The E835S from Sennheiser is a 'dynamic' microphone and, as such, does not require any power source for it to operate.
If you are using several different types of microphone together (dynamic and condenser) it should be quite safe to have phantom power on - it won't cause any damage to the Sennheiser.
However 'ribbon' microphones will be destroyed by phantom power

Unlike 'Dynamic' microphones all condenser microphones require some sort of power supply to make them work. Sometimes this can be by way of an internal battery but many of them work on an external 'phantom' power supply.
I am not familiar with the exact model number you quote but AT make 2 types of AT2020 condenser microphone.
1) If your AT microphone is fitted with a USB plug then you can connect it directly to the USB socket on your computer, which will provide it with the power that it needs to make it work. The USB bus should automatically recognise the microphone and allocate an audio channel to it but you may still have to select this device as your input source in your recording program. How you do this will differ from one program to another.

2) However if the microphone is fitted with a standard jack-plug then it will not work by you just plugging it into your computer microphone input socket as this is not powered. You will need a separate 48volt DC power supply to power the microphone.
You will almost certainly also need some sort of microphone pre-amplifier to match the output voltage and impedance (electrical resistance) of the microphone to the levels required by your audio input socket on your computer.
Probably the best way to achieve both of these requirements at lowest cost would be to purchase a small audio mixer with a phantom power option such as the Phonic AM220 http://cpc.farnell.com/phonic/am220/mixing-console-am220/dp/DP29303

WARNING - most audio mixers only have one on/off switch for phantom, power - thus the power is either on or off for ALL channels. Some other devices - like radio microphones, keyboards and electric guitars may be damaged by having 48v dc current supplied to them

Here is a link to the technical specs sheet for the AT2020 http://www.audio-technica.com/cms/resource_library/literature/49f63e6efc082082/at2020_english.pdf
More information is available here http://www.dolphinmusic.co.uk/article/40-why-do-i-need-a-microphone-preamp-.html

Be sure to use phantom power (48V), as this microphone (condenser type) requires it for use. Hope this helps.

Condenser microphones require phantom power (48v) to operate. Ipod's do not supply phantom power.

Condenser microphones need phantom power (48V) to operate. Some condenser mics use batteries to work and get around using phantom power from an audio mixer. hope this helps

http://i79.photobucket.com/albums/j149/johncheney/todd/IMG_0057.jpg

Original Diagram that came in the box with this microphone!