Brauner Phantom V, I need a schematic!

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Nollman

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I got a Brauner Phantom V really cheap and would like to get it functioning properly. It works but sounds terrible except for the rear diaphragm while in figure 8 mode. That sounds pretty awesome. I tried reversing the capsule but with the same results. The inside of the mic body has burn marks but the circuitboard looks fresh, leading me to think it's been rebuilt. I suspect it's the polarization voltage and ordered some J201 FETs to try that but a schematic would be really useful.
 

Gus

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Post some pictures you don't want to blindly replace parts.
I reads like someone was inside the microphone before and maybe you can repair it.
Pictures by the pattern switching should help figure out how the pattern switching is done. The rest of the circuit might be fine.
Is it Brauner capsule?
Is the switching done like in the 87s, 414s etc. with isolated back plates with 4 wires or is it with 3 wires?
 

Nollman

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With the rear membrane disconnected the front membrane works perfectly in cardiod. What does it all mean? is my capsule wired incorrectly?
Try disconnecting the rear backplate and see if you don't get cardioid on the front membrane.
 

Nollman

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Post some pictures you don't want to blindly replace parts.
I reads like someone was inside the microphone before and maybe you can repair it.
Pictures by the pattern switching should help figure out how the pattern switching is done. The rest of the circuit might be fine.
Is it Brauner capsule?
Is the switching done like in the 87s, 414s etc. with isolated back plates with 4 wires or is it with 3 wires?
At Tim's suggestion I disconnected the rear diaphragm and the cardiod front capsule works fine now. It's a 3 wire capsule with a single back plate. The two connection points look like a dual backplate design but it's a solid ring with continuity between the connector points.
 

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Gus

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2nd picture looks like four 3gig? blue resistors. Two red Wima .01uf?
1000pf(input coupling cap?) and 270pf(connected to the pad switch) polystyrene caps
Is the larger vertical part a inductor going to the gate of the I would guess is a J201 JFET?
Are there two 19.1K, 2.7k, 30K resistors, 201JFET and a greater than 10uf electrolytic cap?

Do the red wires from the capsule go to the red box caps? What does the capsule rear red wire connect to?
A picture of the back of the top board will help

4th picture is that a green Jamercon cap a 1uf Red Wima and what brand 470ufs? I see one COG ceramic a monolithic and two more ceramic disks

If you post the resistor codes and transistors numbers someone should be able to trace it for a schematic

What kind of pattern switching could be used with no DC to DC converter and a double pole center off?(cardiod) switch?

I would check the switch first for proper operation
 

Tim Campbell

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I would guess that the capsule has a short between the membranes or somewhere on the pcb there is a short between the front and rear polarization conductors or that it is really a 4 wire design and you have a short between backplates.
 

Gus

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On the top board does the 100pf polystyrene connect to front and back of the capsule?
The part I guessed as an inductor in rely #6 is it a 560pf or 680pf cap?

question for anyone that has looked a Phantom V before has the PCB solder been retouched or is that how it comes from the factory?

The top board only seems to ever have 3 wires to the capsule
 

Nollman

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Some more pics and a sketch of the components on the disc circuitboard.
 

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Gus

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Could the pattern control it be wired something like shown in the following link look at the schematic
CAD Audio GXL3000 | RecordingHacks.com
Looks like the two inductors(odd the way they are installed if you have worked with a DC to DC that looks something like this you will find how you place the inductors makes a difference) and some parts like the 22pf MIGHT be similar to the type DC to DC in a Schoeps or China microphone DC to DC looks like I guessed wrong in reply #6 with it not having a DC to DC converter for the capsule

I would guess something like a 5:1 output transformer

Is one transistor a BC246D?
 
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Nollman

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Could the pattern control it be wired something like shown in the following link look at the schematic
CAD Audio GXL3000 | RecordingHacks.com
Looks like the two inductors(odd the way they are installed if you have worked with a DC to DC that loks something like this you will find how you place the inductors makes a difference) and some parts like the 22pf MIGHT be similar to the type DC to DC in a Schoeps or China microphone DC to DC looks like I guessed wrong in reply #6 with it not having a DC to DC converter for the capsule

I would guess something like a 5:1 output transformer

Is one transistor a BC246D?
The one nearest the capsule on the disk shaped circuit board is a J201. The ones on the main circuitboard are a C264D on the left and a 550C on the right.
 

Gus

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Measure the pattern switch with a meter you should be able to do this without removing it from the PCB.
Center leg to one side should be open the other way closed often the switched side is opposite the side the toggle is switched to.
Looks like a DPDT so you MOST LIKELY have two SPDT switches side by side.
I am guessing the switch part number is on the other side of the switch by the PCB so you can read it without removing it.

Also check the .01uf caps on the top board to check if they are shorted

Kind of looks like a Phantom C circuit gain stage

There is a different switching DPDT looking switch with 6 connections
 

Nollman

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The switch tests good. I can check if the caps are shorted tomorrow morning. Got chores to do. Here is a sketch of how the capsule is connected to the switch and the 1000pF cap.
 

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Nollman

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Here are most of the values on the circuitboard as they tested. and accompanying pictures. I guess there are a few diodes and a tiny little thing that could be a cap.
 

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Nollman

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Measure the pattern switch with a meter you should be able to do this without removing it from the PCB.
Center leg to one side should be open the other way closed often the switched side is opposite the side the toggle is switched to.
Looks like a DPDT so you MOST LIKELY have two SPDT switches side by side.
I am guessing the switch part number is on the other side of the switch by the PCB so you can read it without removing it.

Also check the .01uf caps on the top board to check if they are shorted

Kind of looks like a Phantom C circuit gain stage

There is a different switching DPDT looking switch with 6 connections
The second switch is the pad switch.
 

Gus

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Had some time so I traced most of the schematic. IF I traced it correctly I think some things could be done better and I don't understand why two things were done.
Some measurements that might help
Voltage at the brown wire, one of the capsules voltages
Voltage at the red wire, the Zener voltage
Voltage at the black wire another capsule voltage, this is harder to do because it is from the DC to DC converter, you can add a cap at the DC to DC output let it charge then measure the less rapidly dropping voltage due to the meter loading down the output.

Other measurements
J201 Drain and Source voltages
BC246D Drain and Source voltage
Transformer center tap voltage

Another test would be to switch the back and fount capsule wires at the PCB side (and do the same test like Tim posted) and test if the issue is capsule related, Switch related or capsule voltage related.
 

Nollman

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I poked around in there and came up with the following voltages and a bit of a surprise. If I hooked up either capsule membrane and the backplate it sounded great (cardioid only) then I hooked up the rear diaphragm to the backplate connector and all patterns worked and sounded good. I think the previous owner had it wired incorrectly. The marks on the circuitboard were from where things were wired when I received it. I'm going to take it home to my studio and test it out more thoroughly and let you know if that solved my issues. A factory schematic would tell me if the connections are correct but Brauner doesn't share them. Meanwhile here are the voltages.
Brown Wire (capsule) 29.7v
Red Wire (Zener) 3v
Black wire -79.6v (was stable and easy to measure)
J201 drain 1.1v
J201 Source .4v
BC264D drain 4.5v
BC264D Source 1.6v
Transformer center tap 29.8v
 
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