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DCC CONFUSED


fac

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Having converted and run several units to Dcc including tts sound.(All Hornby decoders) when having purchased R1230 GWR train set  with dcc ready on the box i believed the fitting of hst valenta TTS sound would be easy.(Although aware i would have to fit contacts/motor to the trailing car.)  However  have found that reading the decoder content on the programming track has given totally intermittent results, sometimes 0 sometimes max 255 sometimes correct but never reliable enough to dare moving to actual track. I have tried both decoders and results are intermiitent in the same way. I know the power is available as the train led flash during read cycle. When writing a change of address  it  confirms but i assume that is only a confirmation of what is written as it will confirm on an empty programming track. It then fails on read. One problem i appear to have is that the time between reads which is at 4 secs, while i can change to say 12 secs it will always revert back to 4 but has been like this for other TTS i have programmed successfully. I am hoping someone can point out a possible silly error on my part or point me in a posotive direction to solution. Thanks Frank.(Hard to know if this is dcc or railmaster topic)

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Further investigation appears to show that pin 8 of the decoder socket is short to pin 1 (One would expect this short to be on the dc plug not the socket) Therefore the decoder output wire (motor) has been short to the right rail pick up when the dcc decoder is inserted. Hornby do not supply wiring or circuit diagram of internal engine wiring with any locomotive, therefore i would have to trace it.  So the problem now is as follows.

Is my set wired incorrectly or is this a build/design error,or is the wiring correct.

Have my decoders been damaged (blown up) due to faulty connection caused by the wiring. (or have they been safegard by the program track output current no obvious sign of damage However that would not be gauranteed..

Has any one else reported/experienced this problem?

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There have been many reports in the past about locos leaving the factory with a short on the socket between a motor pin and a track rail pin. This doesn't affect DC only operation but as soon as you plug in a decoder and place the loco on a live DCC track, the decoder H bridge semi-conductor motor control output stage blows because the high DCC track voltage is applied to the low voltage DC output semi-conductors.

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So if you have fitted a decoder (with the short circuit you have stated you have - i.e Pin 1 to Pin 8) and placed that loco on a live DCC track, then there is a very high probability that the decoder has been permanently damaged.

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The source of the short must be found and rectified before fitting any other decoder.

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  • 2 weeks later...

It would appear that the 'excellant support' statement was rather premature. It was agreed i return the engine and both decoders for checking. Today they were returned without any information supplied. The short on the engine has been removed. Neither of the two decorders would read which suggests they had not been replaced despite as Chrissaf pointed out they would have been blown with the wiring failure known.( Given it was a new set both decoders were tried as one would not expect a wiring fault). When attempting to phone the company at 2 pm i was informed all the lines were closed untill tommorrow morning. It would appear that Hornby are forcing me to take this through Trading Standards. Strange given all their hype on new management which appears more ineffective than that of old. I have now tested the enine with a saphire decoder to be eventualy  used in another engine.

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Actually to give Hornby a bit of credit, they probably tested the loco found the fault, but assumed that the decoders were OK. EMail them again with the issue and I am sure they will respond. I recently blew up two TTS decoders on a Hornby class 66, where the capacitor on the motor had gone short circuit. First one failed, I just assumed it was the module and put another one in, before I realised the loco was blowing them up. They replaced both of them and even gave me the return postage. It seems to take a bit of time for them to respond, but in my case they always seem to do what was right. I am sometimes their harshest critic, but for returns I have never had an issue. Sometimes you seem to have to explain to them what went wrong a few times, for them to get the message, but then when you think about it, they probably are getting issues all the time.

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When discussing the return and obtaining the number it was agreed that i would also return the decoders as they would be expected blown. Telephoned earlier this week to ensure they had my information which was confirmed  with the knowledge of knowing there were two decoders as well. How having found the failure could they not have replaced the decoders? Hornby need to pay attention to their customer care not just rely on being the best available. The only other time i have needed to return an item i was met with a similair pleasing result to yourself, which has made this experience very annoying especialy as it is Hornbys failure. They should have recognised it was their failure and acted with responsobility, which would have included throwing returned encoders in the bin and replacing. 

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If you had a decoder tester like the ESU 59001 unit you could test each decoder to prove it is OK or duff. Maybe there is nothing wrong with them and the fault is elsewhere. Who knows without having them on the bench in front of you to test. 

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I agree that would be a good solution, however it should also be unnecersary unless testing decoders is your thing. The engine Hornby admitted having the failure mentioned. It now functions with a saphire decoder, it now functions with an R8249 (standard decoder) Both Valenta decoders have been reset by writing 8 to pin 8. Both decoders fail to read. Hornby tell me they have tested the decoders as functional, however not with an elink and not in the same engine. (part of the purpose of sending them the decoders as well in the first place). Unless there is some reason i am unaware of with valenta sound decoders being differant i would expect functioning encoders to do so on my system. The only possobility i could see why they should not, the elink prog not having the current capability for the bright lights of the engine on programming, the low resistance of the motor. Both of which would surely apply to the standard decoder. If anyone knows differant and i am missing something obvious please inform as i would be most grateful. Meanwhile i have to return the decoders through the channel i purchased them.

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TTS decoders are based on the R8249 decoder so the same rules should apply.

 

I have Valenta TTS in an older ringfield HST pair with lights and they are no trouble. The motor has been converted to DVD and the filament lights in both cars to LEDs.

 

I can read them either in RM or direct from the Elite. I use eLink as my second controller, but could rig eLink on a second copy of RM and recheck for you, but from past testing I have never noticed any difference in reading TTS or other decoders in RM regardless of the main controller in use.

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I also have fitted 2 off  older HST with DVD motors and led lights, programmed with R8249 with current system (elink) and have had no problems.Which is what makes this more frustrating. In fact i believe had the loco from this latest set not had a dcc socket fitted i would have wired the sound decoders in and had no problems as i would have replaced the current leds and made them  switchable and corrected any wiring failures. But as the plug was there it made for a very quick upgrade.(or so i thought)  Tommorrow i will purchase another set of  sound decoders and have little doubt that when i insert them they will function. If not i will have to diagnose the possobilities further. 

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Unfortunately I do not have an answer for you but if no one can offer a solution you probably know that Hornby offer a no quibble replacement or repair service for the first 12 months. This applies even if it is accidental damage so at least getting another TTS decoder should be no problem. It’s not surprising though that they have returned them to you having told you that they have tested them as functional. If you do get replacements at least you will know more then.

 

I’ve commented because I have the Railroad R3608 which is the same as Railroad model R1230. I bought the Valenta twin pack TTS. Admittedly I have only used one of them as I have not converted the dummy car but can confirm mine works perfectly on an eLink.

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Yes the problem is John i have to return them through the supplier and if Hornby say they are functiional they will return them to me  and no progress will have been made. I have since purchased a twin pack of class 43 hst (MTU) decoders which function no problem within the same engine. I chose not to purchase further valenta decoders as the ones i have (which dont work no communication) have been validated as good by Hornby. I have 34 hornby loco, 10 off fitted with sound decoders 24 with R8249. 2 bachmann engines one fitted with a tts sound module the other a bachmann decoder. The system runs well with few operating failures (usually de rails) It is run from an elink by railmaster software which i believe is NRMA compliant? I assume the test method used by hornby (not elink) is also NRMA compliant. It would appear there is some discrepency in the testing and i can only assume it is my system. I have two seperste systems of elink both show the same result. 

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I wish to thank John and all others for there helpful comments, it is good to know that some have Valenta decoders working on e link systems. I am sure like myself some of you must be puzzled why Hornby proven decoders do not work on my system, although i found it surprising they were functional at Hornby given the circumstance of the original short discovered on the loco. One would have thought Hornby would have tested the loco with the decoders as they were all returned together but i believe they were tested independent. One would also have thought Hornby would have refunded postage as it was their error and given some written detail rather than me having to phone the repair department to obtain any information. I am saddened to have to report my problem about a company that i consider has been a lifelong friend and still a leader in model railway production. I can only think it is an attitude change in personnel and my attitude is possibly out of date.

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I agree with RAF96 a DCC tester is a really good piece of kit. I in the past have had some duff TTS decoders (about 2 to date), putting them on the tester before you put them in the loco gives you a really good feeling. It is one of the best pieces of kit I have bought, it is also good for doing the basic checks, you don't need a piece of programming track. It is like when I was adding "stay alive" to a TTS decoder where I was worried I might damage the unit, I could control it in a defined setting with known inputs. 

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I am pleased to say that Hattons (where the decoders were purchased) refunded my payment by return of post. ( I had to ask for a refund due to Hornbys insistance that these devices were functional.) It is good to know that this retailer has high standards of customer care, something Hornbys repair department might wish to consider and produce a change of attitude within their own company. Perhaps a change of attitude may require a change of personel or appointment of a customer liason position.

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