SE Electronics Z3300a

[Emmathom]

1,697v between the red wire "+" and the white one (on the bad one)

 

[Khron]

There, that wasn't so difficult now, was it?

So that's with both transistors on the DC/DC board removed, right?

 

[Emmathom]

There, that wasn't so difficult now, was it?

So that's with both transistors on the DC/DC board removed, right?

Yes
And look what I have found : the + & - were "glued" by short-circuit
and for what I can see (quite impossible to send a pict 'cause it's so small) there has been a short-circuit for sure (one can see the cooper of the 2 wires)
I have to change these two wires...

 

[Khron]

Hooray for "blind" advice...

 

[Emmathom]

Hooray for "blind" advice...

Yeah, you're right, but what could have been the damage ??? I think I'll be able to put back the transistors (if they didn't suffer)

 

[Khron]

Yeah, you're right, but what could have been the damage ??? I think I'll be able to put back the transistors (if they didn't suffer)

Zero f**ks given during assembly? And/or the previous owner "took a look" very very carelessly...

 

[Emmathom]

Zero f**ks given during assembly? And/or the previous owner "took a look" very very carelessly...

One or the other but not me !
The mic was ok for a couple of hours. I did audio tests oon my last quad tube mic pre... and suddenly it gave up with crackling noise (see the spectrum I recorded)
I opened it AFTER it was OOO (Out Of Order)

 

[Emmathom]

I opened the XLR to measure :
mic connected : 1,96v btw pins 2 and 1 / mic disconnected : 44,24v btw pins 2 and 1
there's a short-circuit somewhere, no ? or is it the transfo ?

 

[Khron]

and suddenly it gave up with crackling noise (see the spectrum I recorded)

I opened the XLR to measure :
mic connected : 1,96v btw pins 2 and 1 / mic disconnected : 44,24v btw pins 2 and 1

Is that NOW, after you replaced those damaged wires?

 

[Emmathom]

Is that NOW, after you replaced those damaged wires?

No I didn't replace them yet, just push them appart to end this possible (surely) short-circuit... but since it's the same situation I believe something is damaged... (remember the 2 tr are desoldered)

 

[Khron]

No I didn't replace them yet

SERIOUSLY???

(remember the 2 tr are desoldered)

Well, how the hell do you expect to get any audio, with the capsule not getting any voltage?

 

[Emmathom]

We don't understand each over... let me go to Google translate and I come back in a minute...

 

[Emmathom]

The microphone gave up yesterday, so:
1) I opened it to take measurements, mainly at the input of the DC/DC card and I noticed a voltage of 1.9v
2) I did the same measurement as the one that works and I found 24v
3) I came to talk about it on the forum
4) after a few discussions, micolas advised me to change the 2 original transistors with equivalent values (see his post above)
5) I opened the microphone (once again) to de-solder them

6) I opened the microphone tonite (once again) to take measurements (once again) and also photos (at your request) and that's when I noticed 2 problems:
- the inductor wire which was wandering on a track (I cut it)
- the 2 power supply wires short-circuited
Here we are now...

 

[Emmathom]

SERIOUSLY???



Well, how the hell do you expect to get any audio, with the capsule not getting any voltage?

When I discovered that the circuit was fed by only 1,9v I stopped expecting any sound... and localize (or so) taht the problem had to do with voltage alimentation

 

[Emmathom]

May I suggest something ?
Now we know where we are and have identified a real problem (voltage) can we concentrate on :
- what damage could this short have done ?
- how to try to fix this mic

 

[Emmathom]

Don't leave please on the side of the road, Khron...

 

[Khron]

Have you replaced those two damaged wires yet?

 

[Emmathom]

Have you replaced those two damaged wires yet?

No but there are pushed appart from each other (like on the pict) so it's almost the same I think... I stopped everything until I am told what to do

 

[Emmathom]

Ok the wires are now new ones

 

[Khron]

Ok, good, finally. Are the two transistors from the DC-DC board, still removed?

Is the voltage between the red wire and ground, still unusually low?