Connectng and Testing 8-Coiler Circuit Board

[Coye]

Hi All,

I recently asked for and have received the 8-coiller circuit board, together with the 8-strand #23 coil.
I have tested the 8 coils with the single transistor SSG and believe that it is now resistance tuned.
So that the next step is to remove the single transistor SSG and replace it with the 8-transistor circuit.
The mystery is how and where to make the connections to this 8-transistor circuit board.

If there are perhaps some pics somewhere? Or if someone has enough patience could they help, please.

What I want to do is bring this machine up slowly, if possible connecting one transistor at the time.

I see there are 24 connection points across the top, and I know there are 16 wires. Two wires are for the trigger coil,
and 2 wires are for the first power coil. My sense about this tells me that the power battery and the charge battery are connected,
but I am confused about exactly where the connection points are.

To be clear:
1. What/where are the connection points for the two ends of the trigger coil, and which one is the
connection point for the top trigger wire?

2. What/where are the connection points for the two ends of the first power coil to be connected,
and which one is the connection point for the top one?

3. What/where are the connection points for the positive of the charge battery, the negative of the run battery,
the negative of the charge battery, the positive of the run battery?

I am looking at it with the heat sink at the bottom and the terminal block at the top. The resistors and other components
are exposed in this view. This means that the number one transistor/#1Tran is at the lower left hand corner.

Once this machine is up and running I will have another story. Right now I just need help making the connections.
By the way I am surprised with testing results so far, with the one transistor circuit. Cheers.

I do have the included circuit diagram, for reference.

- Coye

[John_Koorn]

Hi All,

I recently asked for and have received the 8-coiller circuit board, together with the 8-strand #23 coil.
I have tested the 8 coils with the single transistor SSG and believe that it is now resistance tuned.
So that the next step is to remove the single transistor SSG and replace it with the 8-transistor circuit.
The mystery is how and where to make the connections to this 8-transistor circuit board.

If there are perhaps some pics somewhere? Or if someone has enough patience could they help, please.

What I want to do is bring this machine up slowly, if possible connecting one transistor at the time.

I see there are 24 connection points across the top, and I know there are 16 wires. Two wires are for the trigger coil,
and 2 wires are for the first power coil. My sense about this tells me that the power battery and the charge battery are connected,
but I am confused about exactly where the connection points are.

To be clear:
1. What/where are the connection points for the two ends of the trigger coil, and which one is the
connection point for the top trigger wire?

2. What/where are the connection points for the two ends of the first power coil to be connected,
and which one is the connection point for the top one?

3. What/where are the connection points for the positive of the charge battery, the negative of the run battery,
the negative of the charge battery, the positive of the run battery?

I am looking at it with the heat sink at the bottom and the terminal block at the top. The resistors and other components
are exposed in this view. This means that the number one transistor/#1Tran is at the lower left hand corner.

Once this machine is up and running I will have another story. Right now I just need help making the connections.
By the way I am surprised with testing results so far, with the one transistor circuit. Cheers.

I do have the included circuit diagram, for reference.

- Coye

Hi Coye, welcome to the forum! Answers are below, bit I suggest if you have the circuit diagram you can figure out the connections for the 1st transistor and then the other 7 are the same.

1. What/where are the connection points for the two ends of the trigger coil, and which one is the
connection point for the top trigger wire?
A1: The top of the trigger wire goes to the master base resistor for the 8 circuits. The bottom (the end that comes from the start of the winding) is soldered to the emitter buss.

2. What/where are the connection points for the two ends of the first power coil to be connected,
and which one is the connection point for the top one?
A2: The top of the power winding/s goes to the run battery positive. There is no connection for this on the board. The bottom of the power winding/s goes to the collector.

3. What/where are the connection points for the positive of the charge battery, the negative of the run battery,
the negative of the charge battery, the positive of the run battery?
A3: The positive of the charge battery goes to the output diode buss (cathode side), the negative of the run battery goes to the emitter buss, the negative of the charge battery goes to the positive of the run battery (no connection on board as stated above), the positive of the run battery goes to the top of the power windings.

For the 24 connections I recommend soldering in the appropriate terminal strips (2 x 12 is what is generally available). If you look at the board, the wires are screwed to the terminal strips as [1 leg of base resistor 1][bottom of power winding 1][second leg of base resistor 1], [1 leg of base resistor 2][bottom of power winding 2][second leg of base resistor 2],[1 leg of base resistor 3][bottom of power winding 3][second leg of base resistor 3], etc... This allows easy replacement of the base resistors and also easy removal of the power windings when troubleshooting.

Be aware that the way the board is designed you will not be able to solder in both the terminal strips and the output diodes on the same side. My recommendation is to place the terminal strips on the "component" side of the board and place the output diodes on the "trace" side of the board. All of the other components can be placed on the "component" side and soldered in normally (i.e. component legs are soldered to the traces)

Hope this helps...


John K.

[Rob_Esq]

Parallel resistors on base of transistors

Hi Coye. If you haven't figured it all out yet, this diagram may help.



Please can someone explain the advantage of having parrallel resistors on the base, in a multi-transistor circuit like this, rather than just having a bigger resistor in series? (Other than general system resillience that is ..)


Rob

[Michael Luton]

Rob the individual base resistors helps insure against small variations in the transistors, so they all turn on at exactly the same time

[Tom C]

Hi Coye. If you haven't figured it all out yet, this diagram may help.

[ATTACH=CONFIG]1083[/ATTACH]

Please can someone explain the advantage of having parrallel resistors on the base, in a multi-transistor circuit like this, rather than just having a bigger resistor in series? (Other than general system resillience that is ..)


Rob

What micheal said.... and this also, the individual resostors set a "stop gap" for the current flow to the transistors base, so it does not get blown wide open. The resistor to the branches helps to tune the circuits current draw across all the bases of the trannies. that is why matching components is so important to the circuit. say you have to transistors that show a 56 on your HFe tester on your meter, and then you have 2 that show a 35. then add variations in a 5% resistor, you could see a huge differnce in switching current at the base depending upon where things fell in the circuit.

Tom C

[James Milner]

What micheal said.... and this also, the individual resostors set a "stop gap" for the current flow to the transistors base, so it does not get blown wide open. The resistor to the branches helps to tune the circuits current draw across all the bases of the trannies. that is why matching components is so important to the circuit. say you have to transistors that show a 56 on your HFe tester on your meter, and then you have 2 that show a 35. then add variations in a 5% resistor, you could see a huge differnce in switching current at the base depending upon where things fell in the circuit.

Tom C

Tom, just to get things straight does that mean if the Hfe is matched for all resistors you don't need individual branch resistors? just one in theory one large resistor at higher wattage?
I guess in practice it is good practice and protects the base of each transistor a little more from high voltage?
Thanks
James

[Tom C]

Tom, just to get things straight does that mean if the Hfe is matched for all resistors you don't need individual branch resistors? just one in theory one large resistor at higher wattage?
I guess in practice it is good practice and protects the base of each transistor a little more from high voltage?
Thanks
James

No it means if you like the way it runs you dont need the large resistor. Never run without a resistor on each base, too easy to blow things up.
Tom C

[James Milner]

Tom,
What is the original purpose of the 500ma bulb in series with the common resistor attached to the trigger coil?
Thanks
James

[Rob_Esq]

Thanks Tom and Michael for the info.

[RS_]

James,

The Light Bulb in the trigger circuit, act like a variable resistor, so that as a drive battery runs down, the filament changes resistance keeping the circuit tuned to the sweet spot where it started at when the drive battery was fully charged.......

[James Milner]

Thanks RS_

[James Milner]

Further to the question I asked at post #8 I found this regarding the reason for the 500ma bulb.
I understand it is called the wein bridge oscillator and is helpful in stabilising the wave function in amplitude just as RS posted. But it is always helpful to more clearly understand how it works. For educational purposes I include the link to Jeri ellsworth's video.
Wien Bridge Oscillator - Don't Use Lame Parts - YouTube

[Robert Darrah]

Hi Coye,

Where did you get the board from? Teslagenx? I've got everything together for an 8 filar now except the board, so could use a board soon.

thanks,

Robert

[Tom C]

Hi Coye,

Where did you get the board from? Teslagenx? I've got everything together for an 8 filar now except the board, so could use a board soon.

thanks,

Robert,

We do not have a board designed from JB yet for an 8 coil build, it probably came from rennaissance. send me a PM I may have a couple of those Rennaissiance boards laying around, you can have em for what I paid for em if you want.

Tom C

[Coye]

Robert
I got it from r-charge, fully assembled. There are things about the circuit board that are really quite unique. For example, the screws will not tighten enough
to hold a #23 wire. I finally figured out the way to connect it is by use of clip leads. It was suggested to find some small washers to go behind the screws,
thus to take up the slack so as to accommodate the #23 wire. But I have hit on the clip lead idea, so will use it first.

Coye