SE Electronics Z3300a

[Emmathom]

I ask again:
R5 unsoldered
dc/dc disconnected
transformer secondary wires disconnected
the Phantom powered microphone
How much does it measure at the junction
R3 with R4?

I do it...

 

[micolas]

so as you said earlier, it's a 2:1 or so...

the secondary is wound with thicker wire

 

[Khron]

http://cdn.recordinghacks.com/images/mic_extras/mxl/MXL2001-schematic.gif

Ignore the stuff on the top edge of the schematic, but the audio & transformer output side are the same.

How much does it measure at the junction
R3 with R4?

I was just in the process of asking pretty much the same thing.

 

[Emmathom]

I ask again:
R5 unsoldered
dc/dc disconnected
transformer secondary wires disconnected
the Phantom powered microphone
How much does it measure at the junction
R3 with R4?

43,75v on R3 & R4

 

[Khron]

43,75v on R3 & R4

Ok, now we're getting somewhere!

Phantom power off, wait ~30sec, then solder R5 back, and re-measure. After turning the phantom power back on, of course...

 

[micolas]

43,75v on R3 & R4

now connect the secondary and measure at the same point

 

[Emmathom]

Ok, now we're getting somewhere!

Phantom power off, wait ~30sec, then solder R5 back, and re-measure. After turning the phantom power back on, of course...

41,22v
so (43,75-41,22)/4700 = 0,538mA

 

[micolas]

now connect the secondary and measure at the same point

 

[Emmathom]

now connect the secondary and measure at the same point

like it was before so ???

 

[Emmathom]

now connect the secondary and measure at the same point

2,5v

 

[micolas]

disconnect a wire of the secondary and interleave in series the DMM set to hundreds of mA

 

[Emmathom]

disconnect a wire of the secondary and interleave in series the DMM set to hundreds of mA

ok...done

 

[micolas]

ok...done

power the microphone
how much does it measure

 

[Emmathom]

power the microphone
how much does it measure

5,83mA

 

[micolas]

5,83mA

Looks like bad secondary insulation resistance.
On the DMM at low voltage it indicates well, but at higher voltage it is possible to make a short circuit between some turns

 

[Emmathom]

Looks like bad secondary insulation resistance.
On the DMM at low voltage it indicates well, but at higher voltage it is possible to make a short circuit between some turns

I noticed, when it began to "go bad" that moving the mic does "things" in the Tr aera...
So, wich Tr to remplace it and wich price ?

 

[micolas]

disconnect a wire of the secondary and interleave in series the DMM set to hundreds of mA, but this time to the good microphone, which works well
power the microphone
how much does it measure?

 

[Emmathom]

disconnect a wire of the secondary and interleave in series the DMM set to hundreds of mA, but this time to the good microphone, which works well
power the microphone
how much does it measure?

can't do it now : I will later, sorry...
But in case of big difference, will it mean I have to replace the Tr ? wich ref ?

 

[micolas]

if the secondary is wound second, last, then you're in luck, you can rewind your transformer yourself with the same number of turns and wire section

 

[Emmathom]

if the secondary is wound second, last, then you're in luck, you can rewind your transformer yourself with the same number of turns and wire section

no way my friend !!! I don't know how and don't want to learn... ! enough things to do at this time
this t.bone 2:1 must not be a "formidable" one > I could find a good one at a reasonable price I guess...