Must be the controller

jump cab

The input to the jump port wants a smooth DC input. By smooth I mean no ripple or variance. A simple cab can be built using a 9 volt battery, 50K linear taper potentiometer and a double poll double throw switch for reversing.

Ive built two of these and they work great. They both provided very smooth control.

My guess to your problem is either a wrong connection or the variable output on the old tyco pack is bad.

Randy McKenzie

Virginia Southern

jump cab again

I'd agree with Randy.  I used a well-filtered DC input from a simple one-op-amp "momentum" throttle to run a yard engine on the DCS50 jump port.  No problems at all.

David

Tyco Throttle issues...

Dear Grampy,

If this is the kind of Tyco throttle you are thinking of...

I know that the speed rheostat commonly fails in a manner which results in

- no volt output for first 10 - 30 degrees of throttle movement
- straight to near-max volts thereafter

This is basically caused by a crack in the rheostat/potentiometer track,
with the location of the crack governing where the "jump to full volts" occurs.

I have a few carcasses of such controllers which have been brought to me for "check and possible repair".
In all cases, the user went away with a homebruise tethered walkaround throttle replacement,
which has been a massive improvement in basic operation, and long-term reliability...

Happy Modelling,
Aim to Improve,
Prof Klyzlr

My jump port works beautifully

I'm using a homemade transistor throttle on my jump port, and it works flawlessly.  In fact, it works better than the throttle does by itself, because the output voltage on my wall wart is too low to allow full track voltage.  The Zephyr takes that in stride, and gives what I assume is full speed.

I like the idea of a battery and pot..  I'll have to build one of those!  Now if I cold just figure out a simple way to make it wireless...

Ken Rickman

Jump Port cabs note

I found on my Z that the input of the jump port was high impedance, meaning that my first design didnt go all the way off ( stop ) due to the circuit not being loaded down enough to drop all the way to zero volts. The result was "off" on the throttle but the loco would still creep along.

Simple solution, I added a 1K ohm resistor across the output of the battery powered circuit, in parallel to the Z input. This loaded it enough to drop all the way to zero volts when the throttle was "off".

My guess on their circuit is the input goes to a analog to digital converter, making the input a hi impedance.

My other wall wart powered design used a 100 ohm resistor, provided the same result.

Randy McKenzie

VSRR