Kato RDC help?

[mecgp7]

I have a Kato RDC that I received in parts. I have put it back together and it runs, but it "pulses" down the track. It is perfectly rhythmic go-slow-go, etc. I took the circuit board out and rigged it to run without the board and it runs fine, but no lights of course. This tells me it isn't the motor. Has anyone experienced this? Is there a fix?
I ordered a new circuit board from Kato, but without the parts diagram I ended up with the wrong part.

[central.vermont]

Clint,
Is this DCC or DC?
Also I'm not sure of what circuit board you are talking about. Is it the light boards at each end you are talking about? If it is I
may have a couple somewhere that I removed from mine when I did a DCC install.

Jon

[mecgp7]

Jon,
I believe it's DC. There is one center circuit board, two light boards wired to it, and one other little do-hicky wired to it. Kato does not list the main center circuit board on their site.
Thanks,
Clint

[peteski]

It might be possible that the central circuit board with doo-hickeys is a Digitrax plug-n-play DCC decoder.

[jprince46]

I had the same problem with the one I had. 
Ended up having to solder the motor tabs to the circuit board. 
Once that was done, it ran great.

[alhoop]

I have a Kato RDC that I received in parts. I have put it back together and it runs, but it "pulses" down the track. It is perfectly rhythmic go-slow-go, etc. ..........

I had the same problem with a Model Power Pacific. Ran exactly the same way on DC, ie hunting down the track.
 It had a Digitrax decoder installed that was not programmed to run on DC.

Al

[peteski]

The reason I asked if that center board was a decoder is because the stock Kato board does not have any active components between the track pickups and the motor - just copper traces which act as simple wires.  The only thing that could cause problem would be the contact points between the board, the motor leads and the power pickup strips in the chassis.

[spookshow]

If it looks something like this, what you have there is a decoder -



Cheers,
-Mark

[mecgp7]

Thanks guys. It looks as if I have a decoder. Not having another RDC to compare it with nor the parts diagram, I couldn't tell. I will check it on DCC. I have a Digitrax system, but only use it to test DCC locos for resale.

If it is indeed a functioning decoder then I made out quite well!

Next question is how to convert it back to DC??

[spookshow]

That's actually pretty easy - you just remove the decoder. However, since the decoder comes with its own lightboards, you'll need to re-add the originals. I have a bunch of them laying around if you need any.

Cheers,
-Mark

[alhoop]

That's actually pretty easy - you just remove the decoder. However, since the decoder comes with its own lightboards, you'll need to re-add the originals. I have a bunch of them laying around if you need any.

Cheers,
-Mark

Mark
Why not set the bit in CV that allows DC operation? Asks the DCC neophyte.

Al

[spookshow]

Mark
Why not set the bit in CV that allows DC operation? Asks the DCC neophyte.

When he asked about converting it back to DC, I thought he meant converting it back to "stock". But yeah, if he wants to leave the decoder in and still operate it on DC, then checking bit 2 of CV29 would be a good place to start.

Cheers,
-Mark

[wcfn100]

If he's only going ot run it on DC it may still be better to go back to the old board.

Just because a DCC board will operate on DC, doesn't mean it dual mode.  I'd say the operation could be better on true DC, but these run so fast, who could tell. 

Jason

[peteski]

If he's only going ot run it on DC it may still be better to go back to the old board.

Just because a DCC board will operate on DC, doesn't mean it dual mode.  I'd say the operation could be better on true DC, but these run so fast, who could tell. 

Jason

Jason, if a decoder is not designed for DC operation (dual mode as you call), it will simply not work at all when it receives DC power from the track.

When a dual mode decoder (with DC, or analog operation enabled) works on DC power, there is a lot of things going on in the decoder.  It doesn't just simply pass the DC signal to the motor.  The decoder's microprocessor "brain" measures the DC voltage on the track, then it provides the appropriate voltage to the motor using the same type of PWM (pulse-width modulated) power (through its H-bridge motor-driver transistor circuit) which is used during DCC operation.

To be honest, I don't know if there even are many DCC-only decoders out there.   I think that even from the early days of DCC, most Digitrax decoders (and other brands) incorporated the analog (DC) operation capability.

Mecgp7,  any time you see bunch of doo-hickeys on either the motor, or the light circuit boards, that is a very good indication that it is a DCC decoder.  DC-only boards usually have 4 or less simple components with 2-leads on each component.

[wcfn100]

Jason, if a decoder is not designed for DC operation (dual mode as you call), it will simply not work at all when it receives DC power from the track.

I didn't call it Dual Mode, Atlas did, and they tried to (or did) trademark it.  Early Atlas decoder DID bypass the DCC altogether to run on straight DC.  The early HO models used a jumper.  For N scale the first factory decoders were called eDMD (Dual Mode Decoder).  I can't find any info on these anymore, maybe someone from Atlas can chime it and talk about how they operated.  I don't believe that they worked the same as decoders do now in regards to DC operation.


Jason