Troller dual power pack

[sd75i]

I know drawing is very subpar.  I used ohms.  Lead on red and other lead to the green, then blue both sides.  The I switched leads and measured again.  Just as you said, readings with leads one way and no readings when I switched them around.

[peteski]

You had me confused - you diagram has the green wires (from transistors Emitter  leads) going through the power switch (which made no sense to me) so I checked the earlier photo. The green wires do not go - they go directly to the direction switches. 

Actually, this gives me an idea.  The terminal adjacent to the green wire terminal on the direction switch (with a black wire) is the common or ground.  Measure the resistance between that black wire terminal and the negative on the 18V DC output.  the meter should show 0 resistance (at least to the black wire on one of the direction switches). That will confirm that we know which circuit is the common (ground).

More deductions: Those power transistors are NPN type. The center lead of the transistor is the collector. The orange lead goes to the maximum throttle setting lead of the potentiometer and also to the positive side of the big blue cap.  The negative side of the blue cap is wired to the black (assumed common) wire on the switch.  SO I go back to my theory that those are filter caps for the throttles (not for momentum).

The last set of pictures of the throttle (which I asked for) were nice and clear. Could you try to take a nice clear photo of what is under the circuit board?

Could you also draw a diagram of where all those yellow wires go (under and around the transformer)? And also could you diagram exactly where the glass circuit breaker is hooked up to?

Could you measure the voltage across both caps?  It should be around 20V.

When you slide the momentum switches to either position do the corresponding momentum pilot lights light up and go off?

The power pilot light does light up when the power is turned on?  You might have already mentioned that earlier but I forgot.

[OldEastRR]

This is my favorite thread. Seriously. It's like a soap opera. Or a disaster movie where the good guys are trying to get to the trapped people but their communications are spotty.

[mmagliaro]

So, with the transistors disconnected...

Can you tell me what voltage you get on the "C", "B", and "E" wires, on the
left and right sides, as you turn the throttle up and down?

For now, use the fixed DC accessory "-" terminal as your "minus" for the meter measurements.  And yes, I realize that this might only work one side.
I want to see that "B" terminal wire voltage going up and down.
 If it doesn't, even with the transistor out of the circuit, and even with the "C" having +20v on it, there is definitely another component failure earlier in the chain, probably
on that board that we can't see.

Glass bulb ohm test?  I still think that is important.

-- Max

[peteski]

I had some time to look over the latest photos. This is the circuit I derived from looking at the visible wiring (for one throttle).
When momentum is enabled, it inserts a resistor in series with the wiper lead of the pot. If braking is off then the output from the wiper of the pot is passed to some unknown circuit.  If braking switch is on it shunts that unknown circuitry to ground through a resistor (and disconnects the pot from the circuit).  I suspect that the unknown circuit has a cap which then slowly discharges through the braking resistor.

The question marks at the left side is where the wires disappear under the circuit board.

The top one will be to a source of positive DC voltage.
The output transistor's base goes to the output of the circuit which drives it (and controls the speed).
The light bulb lead probably goes to the source of positive DC voltage.
The center terminal of the Braking switch feeds the input of the circuit which drives the output transistor.

Unrelated to the schematic it appears that the overload light bulb is wired in parallel with the glass circuit breaker.  So once there is an overload and the breaker opens, the light bulb will illuminate until the overload is removed from the circuit.

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EDIT: updated schematic diagram

[mmagliaro]

What you drew is about what I had in my head, especially for how the NPN power transistor is being driven.

That's why I'm so keen to see if there is anything on the Base input to it.

I didn't notice the overload light bulb wire across the overload glass tube. 
That would light if the glass tube were shorted, unless of course
there's no voltage at all getting to the tube or that overload lamp is burned out.

[peteski]

I didn't notice the overload light bulb wire across the overload glass tube. 
That would light if the glass tube were shorted, unless of course
there's no voltage at all getting to the tube or that overload lamp is burned out.

Think about it. During normal operation the glass tube thermal-breaker is a dead short (or close to it).  The light bulb stays dark as there is no voltage across it.  When a high-current overload occurs the thermal breaker heats up and eventually becomes an open circuit. But the high current load which caused the breaker to open is still present in the circuit. Compared to that load the bulb is fairly high resistance. Since the bulb is now in series with the low-resistance load, it sees most of the supply voltage across it and lit illuminates.  It will stay lit until the overload is removed or until the thermal breaker resets. If the overload is still not removed the entire cycle will repeat.

I've seen this type of circuit in other throttles.

[mmagliaro]

Think about it. During normal operation the glass tube thermal-breaker is a dead short (or close to it).  The light bulb stays dark as there is no voltage across it.  When a high-current overload occurs the thermal breaker heats up and eventually becomes an open circuit. But the high current load which caused the breaker to open is still present in the circuit. Compared to that load the bulb is fairly high resistance. Since the bulb is now in series with the low-resistance load, it sees most of the supply voltage across it and lit illuminates.  It will stay lit until the overload is removed or until the thermal breaker resets. If the overload is still not removed the entire cycle will repeat.

I've seen this type of circuit in other throttles.

Yes.  That's how the overload on my own throttle used to work.  I just didn't see the wiring in the photos of the Troller
to figure out that it works that way.

[peteski]

Yes.  That's how the overload on my own throttle used to work.  I just didn't see the wiring in the photos of the Troller
to figure out that it works that way.

Well, I also do not clearly see the wiring in that jumble of yellow wires (from the pilot lamps),  but after zooming in on the photo and making some assumptions I think the odds are pretty good that this is the way that bulb is wired.

I asked sd75i to give us more details on how the yellow wires are hooked up - hopefully that will clarify things.

[peteski]

Sd75i, I have more homework for you to do. 

In addition to the things I asked for few posts earlier, I like you to do the following:

First of all, for all the measurements, make sure that the momentum and braking are off (switch slides thrown to the left when looking at the top of the unit).

I already asked you to measure the voltage across both big blue caps.  If they both show 20V DC or so, then you'll check both throttles. If only one cap has voltage across it, then only test the corresponding throttle.

Place the negative lead of the voltmeter on the negative lead of the big blue cap (on both caps the negative faces toward the center of the throttle case).  Then place the positive lead on the center terminal of the BRAKE switch.  Then take measurements as you are turning the throttle pot of the corresponding throttle.  You should see the voltage close to 0v in the stopped position, to much higher voltage at the full speed position.

Report your findings at once!   

[sd75i]

  Something I can answer right now is yes on/off switch lights up and momentum switches will go on and off with switch.  Brake switches spring back.

[sd75i]

If caps are blue cylinders then I measured black lead to DC access and red to + side of blue cylinder.  0 on left and 20.5 on right.

[sd75i]

I can take more time if this is way to bad.  Y for yellow wire and o for orange.  I'm trying to go in order of my instructions, so please be patient with me.  Thanks

[peteski]

This is helping.
If the pilot lights work on both throttles (and your latest diagram shows that the lights for each throttle look to be powered by that throttle's transformer), that means both transformers are working.

Yes the blue caps are the large blue cylinders.  But instead of placing the negative lead of the meter in the back of the throttle, just measure voltage across each cap.  I suspect that you will see 20V on both caps.

It will also be interesting to see what reading you get on the center terminal of the brake switch (using the procedure  I described in the earlier post).

Are there any additional leads or terminals on the dark side of the transformer (the side not seen in your photos)?    If there are additional wires there, where do they go?

[sd75i]

  Ok I have skipped many things so a scolding is in order.  20.5 across both caps.  Weird thing is nothing with black on blue cap(-) and red on center pin brake switch.  So I try black on blue cap (-) and red on right pin and I get a reading up to 20.5 on right side when throttle on full.  So I try left side and BAM track voltage light comes on.  It stayed stuck on a couple times.  It gets brighter as throttle goes towards full.  I hooked a couple wires to it and touched them to engine and it was working.