TCS VO-1000 "Can not read CV" from factory.

[milw12]

First a little background: I am relatively new to DCC in general. I have an NCE Power Pro 5 setup, and use the supplied procab tomahawk for programming. I have a few other similar installations under my belt that have been successful. I do not have JMRI set up currently.

Last night I installed a new TCS VO-1000 decoder into, well, a new Atlas VO-1000 (Atlas China release with the dull chassis, not the Korean version with the shiny chassis) following the instructions of the website. Made sure there was no static discharge, etc.

Straight from the box to the program track, "Can not read CV" message after a wait. Reset and tried a few times, nothing new. Tried the PAG mode that appears after, still can't read CV's.

Checked decoder/motor, continuity and resistance are as they should be.

Checked for wiring/system faults with a known Kato SD with a K1D4 and everything was normal.

Any one else run into this?

A personal rant: DCC is great when it works. It blows when it doesn't. Especially when there's no information online other than the typical "is the power supply on" tech support-esque crap. "Just reset the CV's"- if I could read them I would.

Two reasons why I want DCC: the Protothrottle (awesome!) and frog juicers because I hate stalls in turnouts. I do like sound but at my pace that's a ways off. Otherwise I'd be in the stone-age with straight DC.

I have a nice little pile of mysteriously scrambled decoders going, must be the Luddite Midas touch!

Back to DC for now.

Lucas

[EL3632]

This is a relatively common problem with systems that use motor readback for reading CVs. I am unsure if NCE does or not, I use Digitrax and DecoderPro/Sprog, and both use motor readback. (Motor readback = resistance from the motor is used by the systems to read and write CVs) The first thing I do when a problem like this arises is check that the motor tabs are making contact with the decoder, and not making contact with the frame (shorts inside engines can end with the magic puff of smoke, but most DCC systems trip the short circuit protection before that happens). Some times the contacts just miss by a couple millimeters and it makes the decoder not read anything, because no motor readback when there is no motor contact.
If that isn't it, make sure your decoder is getting adequate contact from the contact points on the frame. If necessary, add a shim piece or put a blob of solder on to ensure the decoder contacts firmly. Even if your decoder works with the shell off, sometimes the shell moves the decoder in such a way that it loses contact. Make sure the decoder is tight, and does not move.
These are the first things I look for when troubleshooting decoders that aren't reading properly, and usually they fix the problem. Hopefully this is a simple fix like that.

[peteski]

This is a relatively common problem with systems that use motor readback for reading CVs. I am unsure if NCE does or not, I use Digitrax and DecoderPro/Sprog, and both use motor readback. (Motor readback = resistance from the motor is used by the systems to read and write CVs) The first thing I do when a problem like this arises is check that the motor tabs are making contact with the decoder, and not making contact with the frame (shorts inside engines can end with the magic puff of smoke, but most DCC systems trip the short circuit protection before that happens). Some times the contacts just miss by a couple millimeters and it makes the decoder not read anything, because no motor readback when there is no motor contact.
If that isn't it, make sure your decoder is getting adequate contact from the contact points on the frame. If necessary, add a shim piece or put a blob of solder on to ensure the decoder contacts firmly. Even if your decoder works with the shell off, sometimes the shell moves the decoder in such a way that it loses contact. Make sure the decoder is tight, and does not move.
These are the first things I look for when troubleshooting decoders that aren't reading properly, and usually they fix the problem. Hopefully this is a simple fix like that.

Well, using the motor (or often all the other function outputs) to create load on programing track is the only way the decoder and command station "talk" to each other. This is  not specific to certain decoder or command station - they all do it.  Turning on the motor and/or fucntion outputs creates a load (current draw) on the programming track. That is how the command station determines whether the decoder received the programming command.

And yes, DCC is a wonderful control system when it works. However, the more complex the control system is, the more fussy it will be to program and troubleshoot.  Basically each decoder is a complete miniature computer (and so is the command station). So, just as wit the personal computing devices we use: they are very usefull when they work, and pain in the butt when they have problems.

As for the TCS V-1000 decoder, have you tried running it on DCC. My favorite DC tested for N scale engines is a standard 9V battery:  Just hold the loco upside down and touch the battery terminals to its wheels. Assuming that the analog operation is enabled on the decoder in CV29 (it usually is from the factory), then the motor should start running.  That would verify whether the motor is wired properly.

How exactly did you verify the continuity between the motor and decoder, and between the wheels (electric pickups) and decoder?

[milw12]

Thanks for the replies!

It's hard to tell with the contacts, they can't be seen with the decoder in place. Unlike the AMD4, there is no slot to thread the tab through for positive contact, so my preferred option is gone.

I may have been a little loose with the terminology, but I followed this guide: https://tcsdcc.com/mtg and everything checked out. Motor resistance was in the 30 ohm range.

Peteski I did see the 9V battery suggestion in another thread but didn't make the connection (pun intended) to my situation. When powered with a battery, either the front or rear LEDs came on, depending on polarity, no motor. Removed the board and applied power direct to the motor and it ran.

Unless I'm incorrect, we have proper power from the rails to the decoder (indicated by the light). The motor also runs. The issue appears to be between the decoder and the motor, as suggested by EL3632.

Out of curiosity, I reinstalled the factory board and applied power to the wheels and the motor ran. The tabs really do have a lot of 'spring' in them so I would be believe there is contact. Reinstalled the decoder, there was a little slop, especially on one end but it was nothing incredible. Jabbed some styrene as a temporary shim (the Atlas DC board has some neat copper clips that make a nice connection FWIW, first that I've seen of that). Placed it on the program track and was read almost instantly.

 

At least now I know! Between that and adding a battery to the troubleshoot kit I'll have half a chance. I'll conjure up a more elegant shim solution and attempt programming tomorrow but at least I now what I'm fighting against.

After struggling with Atlas locos for a time now, I really have come to appreciate Kato design practices. At least the K1D4's: slide the PC board out, new decoder in, no screws, no hassle.

Lucas

[EL3632]

With those types of decoders, I typically just bend the motor contacts until it hits in the right spot. If you can see the tabs and contacts while the decoder is installed, that helps, but from my experience the VO1000 is not one of those units. Try just leaning/holding the decoder in where it is supposed to go, and see if the contacts line up. If not, then adjust until they do, and then actually install the decoder. This is also easier to do with the frame halves apart, for obvious reasons.

[peteski]

Good troubleshooting  milw12!

I agree with you and with EL3632 that the problem appears to be with the motor contacts not contacting the decoder pads.  Keep bending/forming them and reinstalling the decoder until the motor runs using the 9V battery.  That will be a good indication that the installation is successful.

[milw12]

Popped the decoder out and tweaked the contacts a bit. Also added a better shim job on the loose end. Could program and even ran a little test op today. Appreciate the help from both of you and thanks for patiently walking me through this!

Lucas

[peteski]

Excellent!

[EL3632]

Glad you got it working!