RuudNL

How to get into the High-Z part of an AKG C28?
« on: February 15, 2020, 04:39:07 AM »
I have an AKG C28c for repair, but I don't trust the polarisation resistors (2 x 200 M in series) and the grid resistor (also 2 x 200 M in series).
Now the problem is that these components are in a closed compartment between the amplifier circuit and the capsule head.
But I didn't find a way to get into that compartment...
I tried to uncrew it, but without success. (I don't want to use brute force!)
So, who knows how to get access to the resistors and the capacitor inside this 'magic box'?
« Last Edit: February 15, 2020, 08:51:07 AM by RuudNL »
There is a solution for every problem!

http://www.vansteenisaudio.nl


Khron

Re: How to get into the High-Z part of an AKG C28?
« Reply #1 on: February 15, 2020, 09:30:03 AM »
You probably also came across this, and not sure if it's any help, but...

http://www.saturn-sound.com/images%20-%20microphones/akg%20c28%20-%20component%20parts.jpg
Khron's Cave - Electronics - Audio - Teardowns - Mods - Repairs - Projects - Music - Rants - Shenanigans

RuudNL

Re: How to get into the High-Z part of an AKG C28?
« Reply #2 on: February 15, 2020, 10:25:50 AM »
Yes, I saw this before.
The picture suggests that this part is screwed on, but I can't remove it with reasonable force...
(Maybe this is the result of being 60 years on the same place.  ;) )
There is a solution for every problem!

http://www.vansteenisaudio.nl

Rob Flinn

Re: How to get into the High-Z part of an AKG C28?
« Reply #3 on: February 15, 2020, 04:03:08 PM »
If it seems seized try using some acetone on where you think the threads is.   This is what I use when I service old nikon camera lenses.   If there is thread lock or something like that it is very effective
regards Rob

RuudNL

Re: How to get into the High-Z part of an AKG C28?
« Reply #4 on: February 16, 2020, 04:52:16 AM »
Thanks, I will try that!
There is a solution for every problem!

http://www.vansteenisaudio.nl

Re: How to get into the High-Z part of an AKG C28?
« Reply #5 on: February 16, 2020, 06:27:43 AM »
Also acetone is the only thing I know that will deal with Superglue, or cyano-acrylate glues, whatever their brand name.
Kindest regards,
zephyrmic

RuudNL

Re: How to get into the High-Z part of an AKG C28?
« Reply #6 on: February 16, 2020, 07:49:31 AM »
Good to know that!
There is a solution for every problem!

http://www.vansteenisaudio.nl

MS Vienna

Re: How to get into the High-Z part of an AKG C28?
« Reply #7 on: March 10, 2020, 08:13:05 PM »
Hi,

attached you find an exploded view drawing of the C28 that should help.
No need to dissolve anything with acetone here.

If you are not completely sure you can do that repair without causing  irreversible damage better send it to Mike Amon at mikrofonservice.at
He´s very familiar with  Austrian  mics and knows what he is doing.

« Last Edit: March 10, 2020, 08:16:39 PM by MS Vienna »

RuudNL

Re: How to get into the High-Z part of an AKG C28?
« Reply #8 on: March 11, 2020, 04:09:55 AM »
Thank you! But I managed to solve the problem in the meantime.
There is a solution for every problem!

http://www.vansteenisaudio.nl

 

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