SD35 Chessie stops dead

test the engine with direct power and no DCS signal.

Having protection from the transformer and watching amp draw would be great.

Thursday at 2:14 I tested rails without engine.

Meter registers track at  17+

amps on transformer at .01, at 18 volts,

with SD35 on track, amps at .02.

@Seth Thomas posted:

Thursday at 2:14 I tested rails without engine.

Meter registers track at  17+

amps on transformer at .01, at 18 volts,

with SD35 on track, amps at .02.

@Engineer-Joe posted:

test the engine with direct power and no DCS signal.

Having protection from the transformer and watching amp draw would be great.

Did you connect power directly to a spare piece of track and see if the engine runs?

@Engineer-Joe

Thursday at 2:14 I tested rails without engine.

Meter registers track at  17+

amps on transformer at .01, at 18 volts,

with SD35 on track, amps at .02.

I think what's being requested is:

1. Test engine on track running in conventional mode, not command, and see if the issue persists.

2. Set up a short section of track with nothing connected except power and DCS and see if the issue persists.

I will set up a separate small loop to test in conventional.

I will attempt this probably Saturday. Thanks.

I can explain the reason fairly easily.

You bought a Premier with 2 rail/ 3 rail trucks!!!!

Proto-Scale 3-2 3-Rail/2-Rail Conversion Capable

Why does that matter? Well it means the wheels and axles are isolated to run on 2 rail track, and yes, there is a switch and wiring to hopefully connect those isolated wheels when set to 3 rail mode.

You "doubled down" on the problem using Gargraves track- known to be isolated outer rails. Atlas and some other tracks are the same way.

This combination- along with typically the owner not wiring the track with feeders to connect and bond the outer 2 rails frequently implies you likely have sections of track where only one outer rail is bonded to common.

So what happens is- you have an engine that may not be picking up common from all the wheels on a truck and specifically one sided. You then also have a track that by default does not connect the outer two rails and requires you the owner to account for this when wiring the track.

This double combination of less than ideal electrical pickup situation on the loco and less than ideal track situation with wiring- can result in this exact problem.

It's recommended to move the 2/3 rail switch back and forth several times to clean the contacts to see if that improves the pickup at the wheels. Otherwise many users bypass this switch.

Obviously- more work, but your track system needs the outer rails bonded for best electrical continuity and running of all trains.

Hi if it don't run in conventional check the current draw if it still is

amps on transformer at .01, at 18 volts,

with SD35 on track, amps at .02.

then I would suspect you're board is blown, you can get an ASC MTH TECH to test it for you , where do you live I'm in NJ

As Vernon said if it is a 2/3 engine the switch can be bad or there could be corrosion on the pickup  or even with poor grounds on the trucks ,ps3/2 were the worst design all these engine have had issues ! they are all repairable !

Alan

What about this.
I set up a circle of Lionel tube track. About 6:30 Friday evening.

The SD35 runs on the Lionel track from my first attempt.   I ran the Chessie 5-6 minutes continuously. I’m surprised the engine runs on the rails with a conventional transformer since she was dead on my Gargraves track and my z4000 transformer.

@Vernon Berry

I’m thinking I may have seen a switch like what you are talking about under the hood on the SD35.  

I will definitely be looking for the switch you mentioned tomorrow.

Thank you for bringing this to my attention Vernon.  
I hope it will be as simple as turning the switch back and forth a number of times.

I of course have 3 rail track on my layout.

Switches fail, solder joint break, but more likely is the poor pick up of ground via the right side of engine as it is brush/spring with 2R/3R.  For MTH DCS it is best to have both outer rails connected to ground.  Hence why it runs on your Lionel track.  G

Oh well

I discovered last night late a switch under the hood that I feel is the problem

switch is now on DCC.

After the NCAA madness today I’ll test the switch in DCS mode.

While running the SD35 via the WTIU, This error in switch settings may be the problem.

This evening I moved the switch under the hood from DCC to the correct position of DCS.
The SD35 now operates correctly.

I certainly appreciate everyone’s assistance on this puzzle.

John

@Seth Thomas posted:

This evening I moved the switch under the hood from DCC to the correct position of DCS.
The SD35 now operates correctly.

I certainly appreciate everyone’s assistance on this puzzle.

John

Glad you found the problem John.

@Vernon Barry-

I'm curious how it ran at all if it was set for DCC? I didn't know DCC and DCS were compatible. IMHO- the 2-rail/ 3-rail option is not worth the added wiring, etc., required. Just adds to potential failure points.

From all of the suggestions above, it's always good to go back to the basics and work from there.

Bob

DCC just controls how signals make it to the engine.  Would not affect conventional operation.  Was told could damage board if DCS was attempted, but not sure how or if I have ever seen that.  G