New Kato Mikado 3rd run engine

[peteski]

Like Max said, a 9V battery test would be a perfect way to test the model with pure DC, getting the MRC throttle out of the equation. I always have a 9V battery handy on my workbench, just for this type of testing.  The terminals are spaced perfectly for touching them to tracks or loco wheels.

With a true DC loco, it is impossible for the model to travel in the same direction with the track polarity flipped.

[cjp53]

Lets look at this from a throttle problem,what can I use that would be safe for DC ?I don't plan on running DCC.I have two separate tracks so I would need a duel control.And one that would not  fry a DCC engine if somehow this should happen to me again which I hope never happens.Again being away from the hobby all these years I'm not familiar or up to date.

[cjp53]

Lets look at this from a throttle problem,what can I use that would be safe for DC ?I don't plan on running DCC.I have two separate tracks so I would need a duel control.And one that would fry a DCC engine if somehow this should happen to me again which I hope it doesn't. Again being away from the hobby all these years I'm not familiar or up to date with the technology.

[mmagliaro]

The 1300 and 1370 got a bad rap about possibly damaging SOME decoders (in Rapido engines).  Although I was a heavy contributor to the research thread on the subject, including oscilloscope plots and a circuit modification for the 1300/1370, I still can't say for sure whether the pack or the decoder is at fault here.  What I CAN tell you is that the 1300 uses full-wave rounded, rectified pulses in its output and this is VERY ORDINARY thing for a regular DC power pack to do.  It's not the "pulse power" from the Eisenhower administration.   So there should be nothing wrong with using it. 
EXCEPT....  those nice rounded pulses top out at 25 volts on the 1300, which is mighty high and there's no good reason for it.

Other newer models from MRC like the Tech IV, Tech 6 and Tech 7 don't have such high peak output, so I'd probably go with one of those if you want a ready-made solution.

Oh... so you're not going to open the engine up to see what's going on with it?  I guess I don't blame you, but my painfully keen sense of scientific curiosity really wants to know if there is a decoder, and if there is not, how on earth it's running in one direction no matter which way you flip the direction switch.  My gut tells me somebody wired some diodes or a constant-lighting headlight thing in there, and either miswired it, or a wire is shorting somewhere, causing the motor to always get one polarity from the rails.

[mike_lawyer]

Hey guys, I am the seller of the locomotive.  I have a spare second-run new Kato Mikado that we are going to exchange for the one that was sold.  So we have the situation taken care of. 

Once I get the original loco back, I am going to disassemble it and look for a decoder.  I purchased it several years ago and never had reason to believe there might be a decoder in it, the loco always ran fine.  I will let everyone know what I find.

[peteski]

This thread is like watching a Soap Opera: I'm anxiously awaiting the next episode (post).    Especially fascinating is the unidirectional operation in DC.

[cjp53]

Hey guys, I am the seller of the locomotive.  I have a spare second-run new Kato Mikado that we are going to exchange for the one that was sold.  So we have the situation taken care of. 

Once I get the original loco back, I am going to disassemble it and look for a decoder.  I purchased it several years ago and never had reason to believe there might be a decoder in it, the loco always ran fine.  I will let everyone know what I find.

Thank you for your help,I did not mean for this to drag on the way it did.I'm very sorry and embarrassed. I would purchase from you again as this was not your fault.

[mike_lawyer]

Thank you for your help,I did not mean for this to drag on the way it did.I'm very sorry and embarrassed. I would purchase from you again as this was not your fault.

No problem at all, I was so sorry and embarrassed that the loco did not work properly!  I have bought and sold lots of Kato Mikados before, and they should run great right out of the box.  I know the feeling of disappointment when I buy locomotives and they don't work as they should.

I am just glad that I have another Mikado on hand to make things right.  I will look at the original loco under the hood when you send it back, I am curious if a previous owner put a decoder in there and I never knew it.

[randgust]

Wow, talk about zero degrees of separation...!

cjp, Mike knows his stuff, you're in good hands.   And you don't have to be the investigating agent, although we're still suspect (or at least I am) of your power pack trying to drive in analog DC through a decoder.   Somehow.   Or, it's just haunted as the scientific explanation.   

Max knows his stuff too.   And, with you or without you, this thread will take on a life of it's own.  Don't be surprised.

[peteski]

I hope that I was not the cause of embarrassment with my Soap Opera comment.  That was tongue-in-cheek comment. I'm genuinely fascinated with the problem and will be very interested in the answer.  While is possible that someone installed a bridge rectifier in that model (like Max said), I can't imagine why that would be done.  I too suspect that there is a DCC decoder in there and it  is confused by the pulsing DC voltage from the throttle.

What I learned here so far is that if I ever put any loco up for sale, I'll give it a full test run (in both directions).

[MK]

As The Railwire Turns....in a good way.  All the actors are good actors in this soap! 

[mmagliaro]

I hope that I was not the cause of embarrassment with my Soap Opera comment.  That was tongue-in-cheek comment. I'm genuinely fascinated with the problem and will be very interested in the answer.  While is possible that someone installed a bridge rectifier in that model (like Max said), I can't imagine why that would be done.  I too suspect that there is a DCC decoder in there and it  is confused by the pulsing DC voltage from the throttle.

What I learned here so far is that if I ever put any loco up for sale, I'll give it a full test run (in both directions).

Sometimes people put bridge rectifiers in to make a headlight and/or taillight work all the time in both directions (both polarities).   I'm just guessing something like that plus a wiring failure caused this.  And I'm really glad that  mike is the seller of the engine!  This means we'll all find out what was going on.
Nobody needs to be bothered or embarrassed one whit about any of this.  It's an exciting adventure!

[u18b]

I hope that I was not the cause of embarrassment with my Soap Opera comment.  That was tongue-in-cheek comment. I'm genuinely fascinated with the problem and will be very interested in the answer.  While is possible that someone installed a bridge rectifier in that model (like Max said), I can't imagine why that would be done.  I too suspect that there is a DCC decoder in there and it  is confused by the pulsing DC voltage from the throttle.

What I learned here so far is that if I ever put any loco up for sale, I'll give it a full test run (in both directions).

I busted out laughing.
I thought it was funny and appropriate.

I know I can't wait to find out what Mike discovers.

And CJP53.... please don't be embarrassed.   You obviously noted something was amiss- and we agree with you.  Something's going on.
Railwire should be a great place to ask questions and explore things.

[Point353]

What I CAN tell you is that the 1300 uses full-wave rounded, rectified pulses in its output and this is VERY ORDINARY thing for a regular DC power pack to do.
EXCEPT....  those nice rounded pulses top out at 25 volts on the 1300, which is mighty high and there's no good reason for it.
Other newer models from MRC like the Tech IV, Tech 6 and Tech 7 don't have such high peak output, so I'd probably go with one of those if you want a ready-made solution.

FYI, the rated maximum output of the Tech 7 760 is 23 VDC. Same for the Tech 4 220 and 260.
http://www.modelrectifier.com/v/vspfiles/resources/dc-ac/TECH7_Manual.pdf
https://www.modelrectifier.com/v/vspfiles/resources/dc-ac/Tech%204%20200-220-260%20AB111_121_131.pdf

Tech 7 760:

[SkipGear]

MRC used to sell a voltage limiter diode array to bring the voltage down for N and Z scale. Look up MRC AT880. I have one in my stash someplace but seeing as everything I have will be DCC eventually, I haven't looked for it in a long time.

edit...found it.

https://www.modelrectifier.com/product-p/at880.htm