Adding the DCS - DCC switch to a RK SW-1500

Frank,

It's not necessary to add a switch. Just locate the jumper that keeps it in DCS mode, and lift it off. If you call MTH, they can tell you where is the jumper.

If you like, you can then wire a switch in place onto the jumper pins.

I check with MTH service about putting the engine in DCC mode.

They said that for the RailKing SW-1500 Diesel there is no jumper.

You put the engine on the track, apply DDC power and hit F3 on your DCC handheld controller.

It is on page 14 of the manual.

Frank,

That's news to me! I learned something new.

Me too. I have switches in all of my Proto-3 stuff.

Another quick question.

I took the engine to my LHS to see if we can change to the DCC mode.  It does work.

The shop has meters to measure both voltage and current.

The engine is pulling 1.75 Amps just setting on the track.

Does the engine normally pull that much current with DCS/DCC?

It does not have a smoke generator.

Thanks.

So the engine will pull almost 2 amps just sitting on the track doing nothing?

Hard for me to believe that a PS/3 SW1500 is pulling two amps just sitting idle on the track, there's certainly something wrong there.

I have a 3V PS/2 SW1500, it pulls about 1/10 of an amp just sitting silent on the powered track.  When I do the startup, it bumps that up by almost another tenth.  Yep, that's less than 1/5 of an amp with the audio idling.  At 55 MPH, it was pulling around 1/2 an amp.  This is with no cars, just the locomotive.

If I had a similar locomotive that was pulling 2 amps on the track, I'd be finding out what is wrong with it!  That seems way excessive.

Power = Voltage x Current. 

If the engine is "doing nothing" with 16V DCC track voltage pulling 1.75 Amps that's a whopping 28 Watts.  That 28 Watts is going into the engine.  If the engine is not moving then that 28 Watts is essentially being converted to heat inside the engine and something inside is getting REALLY hot and probably melting!  Like GRJ says, a DCS engine just sitting there should draw just a few Watts.  Even if it has started up with audio at full tilt the audio power only adds a couple Watts max.

I'd take another look at the hobby shop's metering.  DCC track voltage is a digital-like signal that doesn't play well with some meters.

I have to believe either the measurement is way off, or the locomotive is broken.  It's a lot easier for me to measure the pure sine waves coming from my bricks, and they're telling me the same engine in PS/2 is drawing a couple of watts sitting idle!  A couple more to run the audio, and I only get to a whopping 8-9 watts when it's running around at a scale 55 MPH.

The meter that we were using is on for use with DCC.

Well, page 4 of that manual (link below) says there's a DCC/DCS switch...and if you apply DCC power with the switch in the DCS position, the system might overload.

http://www.mthtrains.com/sites...ction/30dl17544i.pdf

Once again, Stan comes through.  After reading page 14, I don't see anything to suggest the locomotive didn't first have to be switched into DCC mode with the physical switch.  F3 is just to do the startup, they're obviously assuming you've already read page 4 and switched it into DCC mode.

I know that some of the more recent RailKing locomotives no longer have the switch, you have to open them up and move a jumper.  However, I don't see anything to suggest this transition is totally automatic.

Once again, 2 amps in idle mode on the tracks is NOT normal!

1. There is no DCS/DCC switch.

2. There is no DCC Jumper in side.

3. When I call MTH service, they referred me to page 14 of the manual.

It looks like they upgrade the electronics in the engine.

I would be VERY unhappy with an engine that pulls close to 2 amps just sitting on the tracks and not moving.  I still maintain there is a problem with that locomotive.  Since I don't have DCC to test, I can't tell you what current other PS/3 locomotives draw, but I'll bet money it's nothing like 2 amps!

Can you post a photograph of the boards inside your engine?  The photo(s) should show all the connectors/cables.  One of us should be able to compare it and tell you which wires to follow that would normally go to the DCS/DCC selector switch or jumper.

Please elaborate on what you mean by "they upgraded the electronics in the engine".  It almost sounds like the downgraded the electronics in the engine to PS2 which did not support DCC!!  If I recall correctly, if you apply DCC track voltage to some earlier versions of Protosound engines they draw more than the expected current.

We've received no ASC bulletins that indicate the PS/3 electronics has been upgraded and these jumpers are changed.  I'd be a bit surprised if they have changed them already.

Doubly so since the MTH website says these PS3 engines were delivered July 2013 so his SW-1500 has been out there 1 year.

I hooked up a Z4000 to a PS2-3V board doing nothing.  With 16V on the track the Z4000 reads 0.1 Amps just as GRJ says.

Then I put a DCC power booster between the Z4000 and the track.  The Z4000 reads 1.7 Amps with the same PS2-3V board still doing nothing.

"In a world that operates largely at random, coincidences are to be expected, but any one of them must always be mistrusted."   Nero Wolfe (fictional detective)

I talked to a MTH tech today.

1. He told me that there is a jumper and told me where it was.  I guess I was given bad information the last time that I called.

2.  He said that the current draw should be about the same for either DCS or DCC.

I am installing a switch in the engine.

Mystery solved.

The current draw is about the same for DCS and DCC for a PS3 engine if the jumper/switch is set correctly.  Clearly this is not the case if the engine is set for DCS and you put DCC on the track.

Color me surprised.   It was hard to imagine they changed the design that radically while we weren't looking.

Can't use a standard multi-meter when measuring DCC power as the ac waveform on both rails are "hot" and a standard meter will show about double normal readings ...gotta use some special gizmo...that's all I know about that  

I've never looked close, I wonder if a true-RMS meter would properly measure it?  I'd probably stick a 'scope on it and figure it out that way.

I took my engine to the hobby shop where I got it from.

We tested it on his set up with the meters.

The engine draws less that one amp.

It look like it is working ok

With the jumper in the proper position, I suspect you're right, enjoy your new locomotive.

I just purchased a MTH 30-1621-1 GS-4 Daylight it does not have the switch for DCS or DCC. Do I need to have a switch to run this locomotive in DCC.  

You only need the switch if you want to switch between DCS and DCC.  Otherwise, setting the jumper once and you're done.

How do I know where the jumper is and what it looks like...

Well, it should be in the manual, which isn't posted on the MTH site.    There's a jumper on the tender board that has to be removed for DCC.  Here's the location of the jumper on the tender PS/3 board.  On the one I have in my hand, it's actually silkscreened on the PCB "OPEN FOR DCC".

The picture appears to be an earlier one as it doesn't have that legend.

Thanks, I have contacted MTH to see when the manual will be posted...

Pop the four screws out of the tender and pull the jumper, job done.

I will give it a try, thanks...