Condenser Mic Maintenance 101

  • Thread starter Thread starter Nate74
  • Start date Start date
OK,
I unsoldered the lead to the capsule and powered up, still had the crackling & popping. So it must not be the capsule.

Will swing by the electronics store this afternoon after work and picking up the required capacitor for crazydoc's test procedure. I'll probably pick up a replacement FET and set of caps as well.

Will get a chance to try it this evening. Thanks to all for your help!!!
N
 
BTW,
I meant to ask this also... is there an online source for manufacturer specific mic parts. I have 5 or 6 mics from a studio that closed down near me, and most are missing various components: shock mounts, stand adapters, etc.

I know I could contact the mfgs directly (Rode & Shure mostly) but wondered if there was another source.
Thanks
 
Nate74 said:
OK,
I unsoldered the lead to the capsule and powered up, still had the crackling & popping. So it must not be the capsule.
Click to expand...

Then I'd say you are lucky. The capsule is by far the most expensive thing here.

Nate74 said:
Will swing by the electronics store this afternoon after work and picking up the required capacitor for crazydoc's test procedure. I'll probably pick up a replacement FET and set of caps as well.
Click to expand...

Please note that Crazydoc exellent suggestion would not work if one of the electrolytic caps is busted. Because they are in PSU filtering all the stages will be affected. If you don't have cap tester, I'd suggest to replace them all with the same values and voltage rating--since there are only three of them, you spend a couple bucks at the most.

Oh yeah, be very careful not to lift traces.
 
Marik said:
Please note that Crazydoc exellent suggestion would not work if one of the electrolytic caps is busted. Because they are in PSU filtering all the stages will be affected. If you don't have cap tester, I'd suggest to replace them all with the same values and voltage rating--since there are only three of them, you spend a couple bucks at the most.
Click to expand...
Good point, Marik. Thanks for pointing that out. It hadn't occurred to me - live and learn.
 
OK,
Home from work and the electronics shop. All three caps and both FETs set me back all of $4.30. Will try replacing the FETs first, then work my way through the caps.

Again, I have to say a HUGE thank you to everyone for their suggestions. This board is an incredible resourse!!!
Nate
 
Nate74 said:
OK,
Will try replacing the FETs first, then work my way through the caps.
Click to expand...
I think only Q1 is an FET, and Q2 is a bipolar junction transistor, so don't replace that with an FET.
 
First off, let me say my eyes are going bad fast. I realized now why I like point-to-point wired guitar amps so much!

The guy at the electronics store, who had better eyes than I, was actually able to read the codes on the components that I wanted to replace and find me the correct replacements, or what he said were correct. The caps were no problem but...The only markings on the Q1 component that was originally in there was "K105" Now I have a "NTE459".

I've got the caps replaced and the Q2 FET, the component at Q1 that they provided has 4 leads and the one I pulled has 3.
I'm guessing one is to the case but I'm not sure how the S D & G go. Shouldn't be hard to try the possibilities though.

If this doesn't work... I may write off the $9.30 :(
 
On a whim, I powered it up without the Q1 component installed, and still got the noise... then managed to damage the resistor R1.

Gettin' frustrated, about to make it a paper weight.
 
Nate,

It seems that you start doing things randomly, which will never bring you anywhere... Never ever fire things up with uninstalled parts, unless you know exactly what are you doing.
The NTE459 replacement for 2SK105 sounds allright.
How do you know that you blew R1? It is a very high Z resistor--1Gohm, so you won't be able to measure it with a regular voltmeter. It is in such location in the circuit that it is impossible to fry it. Also, the currents in the mic are so low that it is impossible to blow anything there.
Q2 is most likely BJT.

But frankly, just send it to me and I will fix it for you for very modest price and shipping. Ultimately, it seems that it might save you money. PM me if you are interested. BTW, hope it doesn't look like spamming ;)
 
Merik,
Yeah, thinking back it was a pretty dumb thing to do. The R1 resistor actually has a crack in it and the lead is very loose.

PM sent on your offer.
 
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