Model Railway Forum banner
1 - 3 of 3 Posts

·
Just another modeller
Joined
·
9,967 Posts
QUOTE (Nitemare @ 15 Oct 2008, 15:32) <{POST_SNAPBACK}>Hi zmil,

Yes it seems that this little Hornby unit is not too popular!!!

I've managed to get some turnouts to work by tweaking the little spring in my Peco turnouts, its far from satisfactory and I'll probably consider some other decoders in future, any suggestions??

Nitemare


*** The decoders recommended by Zmil look fine but with peco point motors they too often need help to make them work!

Your primary problem is not the accessory decoder but the power supply. Hornbys simplistic approach is simply WRONG and cannot succeed reliably.... Besides the excessive current draw of the point motor, solenoids give a very large backEMF pulse when fired and unless the point decoder is very well designed this will fed back to the track bus too.

So:

the ONLY good reason to connect a point decoder to the rails is to get information to flow to it!

You should NEVER use the track power for DCC accessory power - If you want to use the power bus as Hornby siggest then the acccessories should have their exclusive use OWN booster that is NOT track connected.

Ohms law shows the core of your problem very simply:

Ohms law is E(amps) = I (Volts) / R (resistance) or amps = volts divided by resistance.

Peco point motors are 4 ohms and The recommended drive voltage is about 16 volts. (hornbys similar, Seep draw even more as they are 3.75 ohms)

Using ohms law, the current draw at the moment of throw is 4 amps.

You cannot deliver a 4 amp + peak to the point motor via the DCC power bus / rails without problems

(1) Buy Point decoders that have separate power input and use the rails ONLY for communication. OR get a separate booster ONLY for accessories.

(2) Get yourself a good chunky power supply that delivers between 15 and 20 volts and can handle at least 5 amps to power the point motors.

(3) Use heavy wire to wire the point motors. 32/02 or heavier is the ideal

Then the point decoder can work properly, the track power won't be compromised and the point motor will work reliably.

regards

Richard
 

·
Just another modeller
Joined
·
9,967 Posts
QUOTE (Nitemare @ 17 Oct 2008, 01:51) <{POST_SNAPBACK}>Thanks for all the invaluable info.

Would the Hornby Power Booster be the answer then?

Nitemare


***Yes, it may well be however adding more "Hornby cost" is not really the best answer, sorry.

To be quite frank rather than increase the Hornby investment I'd be looking to other brands and progressively changing over the whole of your system if you really want the best from DCC.

Something I should have added earlier: These tips may help without you spending much more money!

(1) Before doing ANYTHING else be very sure the points are not stiff in any way, check that the solenoids you are using are mounted squarely on the point motor AND lubricated with a little vaseline placed in the hole where the slug moves. (a cotton bud is good for applying the vaseline.) Its amazing how a bit of adjustment and lubricant can help.

(2) Try a PL10W point motor instead of a PL10. The W variant is higher impedance and so draws less current and MAY be OK with the existing set-up.

(3) If you are not going to use computer control then be sure you LIKE using an accessory decoder to change points - it takes a minimum of 3 button pushes to do it with a DCC conctroller and for many it gets tedious very soon doing it that way.... because its not as instinctive or relaxed as using a simple switch as a way of operating a layout.

If you do make any changes.....

The Team digital SMD82 is actually quite a good product to start with (I think John at Bromsgrove models stock it) and Ian is having success with it so far, as IanSA is having with the Lenz LS150.

The SMD82 limitation is its need for recharge time, so with extrenally commanded automation its not happy with the rapid command speed for macros from some DCC systems and computer programmes. The limit of the LS150 is its operating power, which does benefit from adding MASTERswitch.

DCCconcepts MASTERswitch by itself isn't DCC control, but will ensure good point firing and lets you use a normal switch instead of momentary + have panel lights. Other DCC using Forum members such as Expat and Ebaykal and others are using them and may give you some further helpful comment.

--------------------------

Having said all that, its still down to your preferences... as to Ians comment on the SMD82 off the bus... its fine powering the SMD82 off the bus on a smallish layout but its not ever going to be the best answer long term or for layouts become complex or that use lots of points.

My advice in that area stands in that every active device adds its own hash and interference to the DCC bus so using the track bus for accessory power becomes a problem eventually for most, even for low power devices, and so for solenoids with their high back EMF and bus loading, its never really going to be the correct thing to do.

regards

Richard
 

·
Just another modeller
Joined
·
9,967 Posts
QUOTE (Nick B @ 22 Oct 2008, 20:00) <{POST_SNAPBACK}>

Once again, I read this forum and find everyone bashing Hornby. What is it with all you people? I have the Hornby R8215 accessory decoders and it sends the point motor firing like a rocket. I have it connected to the track in a tunnel using the Hornby track connector; ie on the DCC bus. The R8247 decoder operates the colour lights no worries.
I always find it amazing that when a person asks for advice on this forum realting to Hornby, they are told to move it on. I have no doubts that there are superior systems. I am not going to argue that Hornby is the best (although for my needs personnally, it is). But I will argue when people say Hornby DCC does not work, or work properly, and in general the flavour towards Hornby is negative. How many of you that offer these negative comments actually have an Elite and various Hornby components? Hmm, I thought so.
For the record, I have an Elite, 3 Selects, 60 decoders of all different types including Hornby, Bachmann, Lok Ecos, and the superb TCS decoders. I will also say the Hornby decoders are silent, and drive the newer Hornby diesel locos superbly. Bachmann 3 functions drive the Bachmanns very well, except fot the 2 function 1 amp versions which are noisy. But the TCS decoders drive anything, including old ringfield motors superbly.
For all those people who use this site as an info source, remember to ask the respondents whether their critiques refer to ownership experience.

*** I am pleased you are having a good experience with the product and have no doubt you are not alone, however whilst I respect your comment and am happy you are enjoying using the gear, many had a very different result.

Personally...My experience is very hands on indeed, from day 1 of Hornby digital, and I am constantly assisting clients with issues relating to the brand. Others on this thread also have considerable hornby experience, with one of them in particular also having spent considerable effort to be positive and constructively helpful to Hornby with clear and concise analysis of problems and supportive feedback.

Hornby have not always been honest about their problems - when released Select was so far off any DCC spec it wasn't really able to be called DCC at all... several brands wouldn't work with the Select and Elite and hornby went to considerable lengths to publicly make excuses and deride and blame the other brands (for example initially hornby simply could not be used with TCS which I too think is an excellent product!).

It took considerable pressure to change that attitude and create understanding of the need for cross compatibility.

Actually nobody is bashing Hornby as a brand at all - most of us are very happy users of their locos and rolling stock in one way or another however there are consistent problems with the digital equipment and while it is improving, the problems are still far greater than with any other brand.

This is not an unsupported opinion, but based on real world ongoing experience and direct feedback from everyday problems faced by clients and associated people. The simple fact is that most initial H releases were extremely poor, and caused many modellers considerable problem and wasted money.

Sadly, while many are better now, and slowly problems are reducing, some items are still not good. Very many modellers remain out of pocket from the early problems.

We know Hornby could do better and we all expect that they will but many who were burned will not forget easily.

As each item improves everyone is happier and the issues reduce and I would expect that when hornby eventually reach their second generation having learned from their very real existing problems, many of the negatives will be finally buried.... but....the truth is that today there are still some considerably better paths to a good DCC experience.

This may (probably will) change as time progresses however until then I for one will always tell it as it is. Honest advice is always better than dancing around the issue.

kind regards

Richard
 
1 - 3 of 3 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top