Bachmann 3T Shay does not move.

[Winget]

I have acquired a used 82698 3 truck shay with factory DCC and Sound. The bell, whistle, lights all work fine and it even makes the chuff sounds when the throttle is moved either forward or reverse, and the brakes squeal then decelerated. The sound/light features work with either my DC or DCC ( NCE Power cab ) but the Loco shows no movement or intent to move. Any ideas/help are greatly appreciated.

[Joe Zullo]

Open the smokebox door and check to see if the direction switch is in either Large scale or Normal. Center would be OFF.

[Winget]

Yes, I have tried the switch in the NMRA and normal positions and still no movement.
Thanks

[Kevin Strong]

The DCC decoder that's in the Shay is a variant of the Soundtraxx Tsunami decoder. I know the Tsunami has a braking feature (F7 or F11, I forget which), where if that's activated, the motors will not move because you've got the brakes applied. Try running the throttle up and hitting F7 and/or F11 to "release the brakes," and see if the loco starts moving. I don't know if the decoder that's in the Shay has this feature or not, but it's worth a shot. I've been tripped up by that a few times with my Tsunami-equipped locos.

Failing that, I'd try to do a factory reset on the decoder. If I recall, all three trucks are wired independently to the board, so when I read that none of the three trucks are turning, that tells me it can't just be a bad connection between the board and the trucks. Now, how you do a factory reset? Umm.... I'll have to get back to you on that one.

Later,

K

[Hunt]

Resetting the sound decoder CVs to their factory default value is a two-step procedure.

   1)  Program CV 8 to 8 (can use either Service Mode or Operations Mode programming)
   2)  Cycle power to the decoder by turning power to the track off and back on

After about six-seconds upon restoring power the headlight and backup light will blink simultaneously 16 times indicating that the CVs were successfully reset. However, if sound or lights come on immediately upon restoring power, the decoder did not successfully reset. Repeat the two-step procedure.

[Hunt]

Kevin,

Note CV 30 = 4, thus the function assignments for F5-F8 are swapped with the function assignments for F9-F12.

[Winget]

Thank you's for the quick responses. I have reset the the CV's several times using Ops mode and service modes changing cv 8 to 8, power down, wait, re-power, lights flash 16 times, sounds come back but still no movement.
I cannot read the value in cv 30 or several other cv's such as cv 115 the whistle. Occasionally I can read the manufacturers cv as 141 and the decoder vera of .080. but no luck with anything else and re-powering between cv reads.
I changed cv 115 to an alternate whistle with both Ops and Service modes and they were accepted every time and cv 8 reset this feature back to factory setup every time.
I have another new, 3 T Shay that works just fine on the same small circle track and I can read the cv;s in service mode with no problem. I thought swapping tenders with each loco might give me some insights but both tenders sound great and move fine with the new Shay but not not the old.
Correct me if I am wrong but each truck ( x3 ) has a separate motor and the DCC board is in the oil/coal bunker?
I have heard that some of the older shays had problems with plastic gears, but I believe that these 3 T shays all have metal gears and are pretty much bullet proof? So I kind of discount this as a problem especially with both of the tenders working.
Thanks;
Brian

[Kevin Strong]

The decoder is in the bunker immediately behind the cab. If you can swap the tenders between Shays, and neither tender works on the old Shay but both do on the new one, that tells me it's likely an issue with the decoder or the motor feeds on the main PC board in the bunker.

Here's a link to the parts diagram for the 3-truck Shay (if you haven't checked it already). http://www.bachmanntrains.com/home-usa/dwg/dwgs/82494.pdf

Pages 13 and 14 are the wiring diagrams; p. 13 is the non-DCC version, p. 14 is the DCC version. I'd try bypassing the decoder by wiring the connector that goes to the decoder to the screw terminals instead, then see if the loco runs fine on regular DC. (For that matter, try running it on regular DC with the decoder intact, first, before disconnecting anything. If it runs fine on DC, then you know the issue is with the decoder itself. If it does not, it could mean the main PC board is bad, not feeding power from the decoder output to the motor leads. (You can check this with an ohmmeter, too.)

Alas, my money's on a screwy decoder. That you're noticing different behaviors trying to read back CVs on one vs. the other tells me something's amiss with the old one. You might call Bachmann's parts department to see if they have a spare on hand, or you can just replace it with a newer board. Soundtraxx just released a 4-amp version of their new "Econami" decoder which should work well. I just got one for Christmas, but I haven't had a chance to play with it yet. Early reports, though, are pretty favorable.

Later,

K

[RIrail]

You say you are powering it with the NCE power cab? If that is the case the power cab without any additional booster is only 2 amps. The three truck shay has three motor blocks and is probably drawing more than 2 amps when the motors try to turn. My guess is that is why everything works except the motion.
Steve

[Kevin Strong]

I'd suspect since the "new" Shay runs okay on the PowerCab, the old one should as well.

Having said that, it does not rule out the possibility that one of the motors is bad, possibly drawing a bunch of current. (It'd be one of the motors on the trucks on the Shay, not the third one under the auxiliary bunker, as that's been shown to work.) Running the loco on "analog" DC would sort that out. Use an ammeter to see how much current you're drawing. With that loco running light, it shouldn't draw more than 1 amp total, and all trucks should turn at the same speed. If one of the motors is bad, you'll likely see it drawing a bunch more current (2 amps or more) and one truck--the bad one--will be running differently than the others. I had this happen on a 2-truck Shay.

I don't know how the ProCab handles current overloads. My MRC Prodigy shuts everything down and gives me warning lights when its current capacity is reached.

Know also (and this isn't an issue with the PowerCab) that the decoder that's in the Shay is limited to 21 volts maximum. Anything above that, and it goes into over-voltage shutdown. Since you acquired the first Shay used, there's a possibility that someone tried to run it on a DCC-powered layout that had 24 volts on the track. I think the over-voltage shutdown should have kept things safe in that scenario, but these are electronics. Weird things happen.

Later,

K

[Winget]

Thanks for the replies, Steve and K. I bought the power cab for my HO layout, bought the new G scale shay for display then fell in love the big stuff! The power cab is the only DCC system I have access to and it drives my new 3 T shay with no problems.

I will try and measure the voltage with my DC ( analog ) power pack. If I have read the schematic correctly green and orange are motor power to all 3 trucks.

Brian

[Winget]

 :)Thanks all!, for your help, it has taken more time than I thought, much reading and have learned a great deal about DCC, DC, using a multi-meter and programming DCC capable locos and I believe my problem has been resolved.
I connected my multi meter in series to read amperage draw with an Arirto-Craft DC power pack 0-21 volts for the new DCC equipped Shay that would run and recorded the amperage draw .20Amps hear sound, .30Amps loco starts to move and .90Amps loco running full out.
These values are well below my NCE 2.0 amp power pack restrictions of 2 amps total and the 1/4 amp program track provisions.
The used Shay recorded .12Amps with a steady sound but no movement or increased amperage draw as I increased the voltage 0-21 Volts, so thus I thought no motor problems.

I was hoping for an easy programming solution, So I finally removed the oil, coal cover and discovered a loose orange wire from the top board to the lower board receptacle and low and behold it responds just fine,
Thanks again;
Brian

[RIrail]

Brian, glad to see you were able to find the problem and fix it yourself. You are now that much more experienced the next time you have an issue.