Troller dual power pack

[mmagliaro]

So you hooked the "-" meter lead to the case, and the "+" lead to the B, and got nothing? 
Maybe Peteski's on to something.  Maybe reading between the "-" capacitor lead and the B will show something.
I guess it's possible the case isn't grounded or the circuit isn't grounded to the case at all.

Good luck.  I like Peteski's tests.

[peteski]

In my experience if this type of 120V AC powered device has a metal case, if it is grounded, it is usually done to the AC-side ground (via a 3-prong plug). If the device has a 2-prong plug then the case is usually is electrically neutral. The low-voltage internal ground is usually not connected to the metal case.

[Carolina Northern]

Pete,

The blue caps are probably part of the momentum circuit. There are no caps in the non-momentum version.

The transformer thing confused me enough that I drilled my dual pack and it only has one transformer - but it's the same as the two in his pack. My guess is that since his is a higher current, they added the extra.

I can only speculate that the extra winding are used for the Acc outputs? Most of what I've had open before are single throttle units. They only have an AC ACC and it comes straight off the transformer Approx 18 VAC.

Troller made it very hard to get to the circuit board - the terminals come in and fasten from the front of the pack and the circuit board is heavily soldered to the terminals. On his, it would take unsoldering all eight of the terminals to flip the board. Hard to see makes it hard to trace. I can flip my non momentum one, but don't know how close it will be with the extra circuitry.

I'll find a low voltage ground for a ref point - maybe that will at least carry over.

Don

[Carolina Northern]

I revisited the entire thread and nowhere it was stated that those voltages were ok on the defective unit.  Maybe, like me, you were confused by Rich_S's instructional posts (with photos).  But I did ask whether the earlier photo of the unit's faceplate with the lights illuminated was of the defective unit or some random photo off the Internet.

Pete,

He's posting variations of the same post on three forums - I must have read it on one of the others - sorry.

Update - from trainboard  There are 8 plugins on the back. Throttle 1 and 2 do not light up as well as work at all . AC plugin and DC Access both show voltage.

Don

[peteski]

Pete,

The blue caps are probably part of the momentum circuit. There are no caps in the non-momentum version.

The transformer thing confused me enough that I drilled my dual pack and it only has one transformer - but it's the same as the two in his pack. My guess is that since his is a higher current, they added the extra.

I can only speculate that the extra winding are used for the Acc outputs? Most of what I've had open before are single throttle units. They only have an AC ACC and it comes straight off the transformer Approx 18 VAC.

Troller made it very hard to get to the circuit board - the terminals come in and fasten from the front of the pack and the circuit board is heavily soldered to the terminals. On his, it would take unsoldering all eight of the terminals to flip the board. Hard to see makes it hard to trace. I can flip my non momentum one, but don't know how close it will be with the extra circuitry.

I'll find a low voltage ground for a ref point - maybe that will at least carry over.

Don

LOL - I thought those were to filter the raw rectified DC voltage. I forgot that it was mentioned earlier that this pack supplies unfiltered DC to the track.    Still, there might be a good chance that the negative side of the cap is the common ground for the throttle.

This also implies that the DC output of the throttle is not true DC but unfiltered output from the rectifier.

As far as 2 transformers go, it makes sense if the throttles are supposed to be fully independent electrically.  Sure, they could have used a larger (power-wise) transformer with multiple separate windings, but those are hard to find and more expensive than using what they already use for single units. At least that is the speculation.

If this remote troubleshooting is taking place on 3 forums, I can imagine that there will be some serious head-spining. 

[mmagliaro]

Those cap negative leads seem to go through a resistor, the control pot, and a slide switch.
Maybe they are on the negative supply, but I wouldn't count on it.

How about this?  The fixed DC accessory output terminals on the back of the throttle are working.
Wouldn't the "-" output terminal on the fixed DC accessory termianls have to be a good ground reference we can use?

[Carolina Northern]

Max,

that was what I was thinking. Couldn't hurt to try.

Don

[Carolina Northern]

LOL - I thought those were to filter the raw rectified DC voltage. I forgot that it was mentioned earlier that this pack supplies unfiltered DC to the track.    Still, there might be a good chance that the negative side of the cap is the common ground for the throttle.

This also implies that the DC output of the throttle is not true DC but unfiltered output from the rectifier.

As far as 2 transformers go, it makes sense if the throttles are supposed to be fully independent electrically.  Sure, they could have used a larger (power-wise) transformer with multiple separate windings, but those are hard to find and more expensive than using what they already use for single units. At least that is the speculation.

If this remote troubleshooting is taking place on 3 forums, I can imagine that there will be some serious head-spining. 

Let's just say that you and Max have gotten him a lot further than on hte other forums.

[mmagliaro]

Let's just say that you and Max have gotten him a lot further than on hte other forums.

I appreciate that (and I'm sure Pete does too).
I know this is tedious, but remote-control diagnosing isn't easy.   So if the OP will hang in there, I will hang in there.

A huge key will be seeing what's going on with those B,C,E terminals on those transistors.
The fact that the throttle light came on when he accidentally shorted the C to the B terminal tells me that
there good +V getting to the throttle circuit (and since the accessory terminals work, that's what I would have bet).

Now, I just REALLY wants to know if the B or E lines are going up/down with the throttle control,
once the meter is connected between there and a valid ground reference.  If there's nothing on the "B" terminal,
this is going to get a whole lot more complicated.  I'm really hoping he sees the B voltage going up and down and nothing
on the E.

[peteski]

How about this?  The fixed DC accessory output terminals on the back of the throttle are working.
Wouldn't the "-" output terminal on the fixed DC accessory termianls have to be a good ground reference we can use?

Treating the negative side of the fixed DC output as a common voltage reference? Sounds logical to me.  Good idea!

I'm glad that TRW troubleshooting team is leading!   

[sd75i]

  While it is true I posted it on 3 forums,  this forum is moving me forward and I much appreciate the patience you have with me!   I really want this to work and have faith I will get there with the help of this forum.  Vanning home now, so I'll get to blue things tomorrow.  The case is metal.  Should I try and ground some other way?  Thanks again to all!!

[peteski]

Sounds like you should forget the big blue caps and instead try to use the negative terminal of the constant DC output as the ground (common) for the multimeter (while you take voltage measurements at the B, C and E).

Could you also post photos of the top of the unit and the back of the unit.  Not just closeups but the complete back and complete top. So we can see all the legends for all the switches, knobs, and terminals.

[mmagliaro]

+1   YES.
Yes the neg terminal of the fixed DC outputs as your reference, not the case or the blue capacitors.

[sd75i]

  Ok, i used black lead on - D.C. Access and red on B, C, E.    Left side 0, 0, 0.  Right side 0, 20(0-full), 0.  All 0 readings were throttle 0-full.

[mmagliaro]

On the right side, the C (collector) went from 0 to 20 as you raised the throttle up and down?
But the base stayed at zero the whole time?
And the left side all 3 are always zero?

I hate to say this, but it is really starting to sound like that circuit board has got to come out
in order to see what wires are going to it and what voltages you are getting in there.  This would be
so much easier if we could trace the voltage from the transformer, through the rectifier (which has to be on
that board somewhere), and forward, to see where it dies. 

Is it right that the board can't come out without actually unsoldering it from those 8 rear panel connectors?
Ugh.  What a design.

Before we go to that step, can we go back to tracing all the wires from BOTH transformers and telling us
where they all go?  We never did get that part done, and I think it would be very useful at this point.