S-1 switcher speed

[roundhouse foreman]

Hi All,

GrFr was foreman of Niagara Falls roundhouse That got me started, but...
I have 2 ea S-1 switchers Bachmann and Atlas DC only
Atlas screams around the Bachmann.
Disassembeled Bach and tested w/wheel contact. Runs as w/cover on, lights sw w/direction change.
Apply dc to top connection of motor and motor screams as the Atlas did, w/o lights coming on.
Now apply dc to wheels and back to slow speed and lights dim and glow w/dc amt of dc applied.
Seems that the lights are connected in series to have this effect on the dc avail to the motor.
Shouldn't it be parallel thereby not robbing amps to the motor and keeping the lights the same glow no matter what speed

Thanks rhf

[bapguy]

If this is the DC ready one, I would guess you have LED's not bulbs. Do they glow orange? If so they're LED's. LED's have resisters wired to one side of them as the work off a low volage. If the track power goes through the resisters then to the motor this is why the Bachmann unit runs slower than the Atlas unit. Joe

[richg]

The power from the wheels to the motor does not pass though any resistors. Yours might have two green devices that look like resistors and connect to the motor but are inductors which have very little resistance.Those inductor form a filter with a cap or two or three caps to satisfy the EU and UK interference standards.

Rich

[jward]

does the bachmann have a decoder? if so the decoder itself is robbing the motor of about 5 volts, thus making the top speed voltage about 7v on dc. without a decoder, the top speed voltage should be 12v.

[roundhouse foreman]

Thanks for the replies guys,

The unit I have has the two pc boards l/s, no decoder, and the lights appear to be std filament bulbs.
DC across tracks vs DC across motor is about 2 x more, or 1/2 at motor a serious loss of power. Values taken across track and from track to top terminal of motor having different settings on a basic spectrum magnum trans as source.


rhf

[richg]

I could not find the S1 diagram anywhere but many of the Bachmann locos have a eight pin NMRA connector on the PC board. When the DC jumper is plugged in, the wheels are directly connected to the motor contacts via two inductors. Some locos have a wire wound inductor. Some have a what looks like, green resistors that are inductors. Inductors have very little resistance. Much less than one ohm.
Trace the wiring with your ohm meter and visual inspection.
A few small locos have metal tabs instead of a plug type DC adapter.

A photo of what you have would help a lot. A photo is usually worth a thousand words.

Rich

[jward]

you could not find the s1 diagram because Bachmann does not make an s1. they do, however make s2 and s4 models, as does atlas.

[roundhouse foreman]

Crushed wire found when changing to DCC.
Zips right along now.
Thanks for the insight.