DCC layout problem

[KiwiB]

Hi Guys

I'm having a problem with my layout but I not sure if it's a track, loco, or controller issue.

My track is based on the Hornby track matt with an extra loop around the outside. It is made up of Hornby set track pieces, including 15 turnouts exclusively. Power is supplied to the track via bus wires and 130 odd droppers. Each track either is connected to droppers or is directly connect to a track with droppers. Including the turnouts.

Control is via a Hornby select version 12, with a 15V, 1A power transformer, powering the locos only.

This is the problem I have:

I have 3 loco's. A Hogwarts Castle I purchased with TTS sound fitted. It circles the entire layout with no problem. All sounds operate and it runs very smoothly.

I have a Terrier which I purchased with DCC. This runs very jerky and it stops in places it often requires a little push to get it going and needs to be run at a higher speed to be kept going.

I also have a Railroad Flying Scotsman, which I add a TTS chip, very simply by plugging in the 8 pin plug and extending the speaker wires in to the tender. This loco will not run at all. When power is supplied the steam sound comes on and the horn sounds. It won't move when the speed dial is turned up. If I give it a little push the sound cuts out then restarts again with the horn sounding, and this will happen around the entire layout.

I have tested every inch of the track with my volt metre and I get a consistent 5.5v.

Any help or advice will be much appreciated.

Kind Regards

[Chrissaf]

Select with version 12 [1.2] firmware is now old and potentially has issues with TTS decoders. I highly recommend that you have the Select firmware updated by Hornby to version 1.6 [cost typically £15]

Using a multi-meter to test for DCC track voltage can not be replied upon to read accurately. Your 5.5 volt reading should be nearer 14.5 volts, but your lower than expected 5.5 volt reading might be due to the quality of the meter you are using. DCC track voltage is a high frequency alternating square-wave at a nominal 7,000 cycles per second. Most meters are calibrated to read correctly an alternating sine-wave at 60 cycles per second.

I assume your 5.5 volt reading has been taken using the "AC Voltage" range set on your meter and not on the "DC Voltage" range. If the 5.5 volt reading you are seeing is genuine and not the expected 14.5 volt level, then either your Select or Select power pack is showing a fault condition.

[KiwiB]

You are quite correct. I just check my reading and on the proper setting I get 16.1v around the track.

[Chrissaf]

In which case I would be focusing on the Select firmware level. However, I now realise that you [KiwiB] may be located in 'New Zealand' where the postage costs of returning the Select to Hornby for a firmware upgrade does not make that such an attractive option.

PS - 16.1 volts is acceptable. Your meter calibration means that your meter is just reading a little on the high side.

Unfortunately with TTS decoders, one cannot rule out the possibility that it has been shipped to you in a faulty condition. TTS failures are high. It is possible that only the sound part of your TTS decoder is actually working. Your Select 1.2 firmware does not give you the option of performing a decoder factory reset, something that version 1.6 can do. Full support for TTS decoders was added to Select firmware version 1.5

[KiwiB]

Yes I'm in NZ, so sending the Select back to Hornby is not really viable. I understand there is a power transformer with higher Amps. Would that make a difference?

[Chrissaf]

No ... that is not a viable solution. Your revised 16.1 voltage reading is indicating that availability of power is not the cause of your issue [barring faulty kit]. As I said in last replies, early Select firmwares are known to have issues with Hornby TTS decoders, but with the caveat that your TTS decoder may actually be faulty. The only way to prove that would be to try it with a borrowed controller preferably used in conjunction with a decoder tester. Can you take your TTS decoder to a model shop to have it tested on their test bench?

[Going Spare]

With regard to the erratic running of your short wheelbase Terrier loco, I would check the cleanliness of the rail surfaces, the wheel treads, the backs of the wheel rims and the pick-up contact heads as well as ensuring those contacts are correctly positioned so that the heads bear on the wheel rims at all times (the wheelsets can move slightly sideways across the chassis and when so deflected, contact with the pick-ups may be lost).

[96RAF]

Not sure which TTS decoder is fitted to your Scottie but it should have a whistle or two not a horn.

[Chrissaf]

I have just noticed that you say:

Quote "A Hogwarts Castle I purchased with TTS sound fitted. It circles the entire layout with no problem. All sounds operate and it runs very smoothly."

If your statement that your Select is firmware version 1.2 is correct, then it is not possible for all the sounds on the Castle to be functional. The 1.2 Select firmware only supports F0 to F8, the Castle TTS decoder has additional sounds in the F9 and above function range.

However, since you your say that the Castle 'runs' fine from a motor control point of view, then that is pointing even more to the TTS decoder used in the FS TTS being faulty.

[KiwiB]

Good morning Guys

My green...ness in this hobby is been highlighted.

96RAF, you are correct it is a whistle. Chrissaf, All functions to F8 perform as per described in the instructions.

I have cleared the rails with a track rubber, and it appears to be clean. The Terrier is brand new. I haven't pull it apart but after a visual inspection the contact look to be fine.

Unfortunately none of the retailers have a track set up. However I understand there are a couple of chaps that repair and maintain locos. I'll see if they'll test the FS and Terrier for me.

Thanks for the help so far. Any more thoughts or things to try will be very much appreciated.

Kind Regards

[96RAF]

F0 to F8 is the normal limit of sounds you can operate at that Select revision. Unfortunately you cannot remap the more often used functions onto the available F-keys.

Something that has been pointed out previously by Colin is that the fit of the pins on the TTS plug is not always tight with the sockets in some locos. To some extent this can be improved by a bodge i.e. bending the plug pins a little bit. I have managed to tighten up a sloppy fit by tinning the plug pins but you don’t need much - put it on and wipe it off. This then makes for a reasonable fit as you mate the plug into the socket.

The other thing to look for is to lift the socket and check for solder tracking or stray wires across the pins as poor build quality is not unknown. Also make sure there is no chance of the decoder touching anything metal, using tape on the metal bits rather than wrapping the decoder.

Fault finding can be frustrating task but if approached logically at some stage the fault will be traced and fettled.

[Fishmanoz]

Despite the NZ/postage issue, I’d still seriously consider sending the Select back for upgrade. Ring HCC and discuss it with them.

[KiwiB]

I re-examined the pick ups on the Terrier last night, and as noted by GS I discover that on 1 of the wheel sets as it moved sideways it lost contact with the pickup. We talking fractions of a mm. So I removed the bottom plate, added a little more sideways spring to the pickups, and now I have the Terrier and the Hogwarts Castle circling the layout with no problems. I feel however that with the Terrier this not a 1 time fix and I would suggest it may need re-tweeking periodically. Still! 2 down 1 to go.

Just the FS. I've sent this of to the Loco Dr. I'm sure he will discover and issue.

As the FS is the Railroad version, it doesn't have pickups in the tender. Does Hornby offer a retro fix kit so I could add these pickups myself?

I'm considering biting the bullet and purchasing the Elite controller. It is a little expense in NZ at $650. But I think I will also take your advice FI and call HCC.

Kind Regards

[96RAF]

Folk have upgraded various railroad models by pulling the later model service sheet and either converting their own tender chassis frame to accept pickups and retro fitted the 4-pin plug and socket but the easiest way is to source a later chassis frame complete with pickups, power transfer socket, decoder socket and speaker mount and just transfer the old body to it. The loco will need some rework to splice in the plug portion of the power transfer and bypass the old decoder socket. The plug (x6311 from memory, but check the service sheet) is readily available as spares.

[Fishmanoz]

There are many FS models produced but my Railroad version comes with tender pickups via connections on the tender post. It is one of my smoothest runners. I suggest you double check yours?

[KiwiB]

Good afternoon Guys

Just to update, the diagnosis from the Loco Dr, as suggested by Chissaf is a faulty TTS chip. It's a shame the TTS cards are not more reliable. Anyway at least we've tracked down the issue, thanks for your help.

Kind Regards

[96RAF]

Thanks for the feedback Kiwi.