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Condenser mic repair

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Glaswegian

New Member
Hi, any ideas would be appreciated.
I've been trying to repair my old (maybe 97' model) CAD live microphone it's a hand held condenser. It looks similar to a C195 but I guess mine is an older model it's black also but has a gold ring around the middle.
I gave it to a repair guy and he said I shouldn't worry about it as it would be too costly etc..easy for him to say but I don't have spare $300. He left a screw out when he gave it back and a lot of the internal wires pulled out of the curcuit board so I've basically soldered it back together with my limited instinctual knowledge as I couldn't find an online diagram. Not sure if it's actually stuffed or I've just wired it up incorrectly. When I plug it into my XLR cable and into the mixing desk I hear a loud hum when I touch the actual silver mic section, when I take my hand away it stops, but it's not actually working. Check out the photo's at these links.
hk9d2-1.jpg

hka0e-1.jpg

hk9kr-1.jpg

hk9h7-1.jpg
 

mvs sarma

Well-Known Member
Hi, any ideas would be appreciated.
I've been trying to repair my old (maybe 97' model) CAD live microphone it's a hand held condenser. It looks similar to a C195 but I guess mine is an older model it's black also but has a gold ring around the middle.
I gave it to a repair guy and he said I shouldn't worry about it as it would be too costly etc..easy for him to say but I don't have spare $300. He left a screw out when he gave it back and a lot of the internal wires pulled out of the curcuit board so I've basically soldered it back together with my limited instinctual knowledge as I couldn't find an online diagram. Not sure if it's actually stuffed or I've just wired it up incorrectly. When I plug it into my XLR cable and into the mixing desk I hear a loud hum when I touch the actual silver mic section, when I take my hand away it stops, but it's not actually working. Check out the photo's at these links.
hk9d2-1.jpg

hka0e-1.jpg

hk9kr-1.jpg

hk9h7-1.jpg
the links are here reproduced
https://twitpic.com/hk9d2
https://twitpic.com/hka0e
https://twitpic.com/hk9kr
https://twitpic.com/hk9h7
please see whether this link helps
The Lektropacks AV Guide - XLR Connector Wiring Diagram
 
Last edited:

audioguru

Well-Known Member
Most Helpful Member
I guess you must post pics over at Twit instead of here because you are a NOOB and this site stops NOOBs from posting SPAM.

Hum is caused when the cable's shield is not connected because then the cable picks up mains hum that is radiated by mains wiring.
 

mvs sarma

Well-Known Member
I guess you must post pics over at Twit instead of here because you are a NOOB and this site stops NOOBs from posting SPAM.

Hum is caused when the cable's shield is not connected because then the cable picks up mains hum that is radiated by mains wiring.
I see. Then newcomers won't be able to place a photo and seek clarification. Actually the links could be seen only when the OP's message was quoted at the the time of typing reply. Later again, as reply is posted, the links disappeared.

As You also indicated that the links he posted did not show the photos, I thought perhaps it could help to sort his problem. how ever, I posted the links only and not the pictures themselves.

BTW, I doubt whether the Red and Black wires at the male connector are reversed.
 
Last edited:

Glaswegian

New Member
Cheers for that. I think I know the XLR wiring. Not sure if the wires are correctly soldered onto the circuit board at both ends.
 

Glaswegian

New Member
I guess you must post pics over at Twit instead of here because you are a NOOB and this site stops NOOBs from posting SPAM.

Hum is caused when the cable's shield is not connected because then the cable picks up mains hum that is radiated by mains wiring.

Ok, thanks for that. So would that explain why the hum is only present when I touch the end of the mic area?
 

mvs sarma

Well-Known Member
Cheers for that. I think I know the XLR wiring. Not sure if the wires are correctly soldered onto the circuit board at both ends.
as seen from soldering side, the pins of male plug were defined and I fear if the active wire ( pre amp output) has gone to the pin meant for ground. So, I felt that it could be cross checked. iof the board diagram could be reverse engineered, perhaps many clouds can be cleared.

AG is right in saying the cable's shield(screen) should be connected to ground.
 
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