Hornby A4

I really like my Hornby A4 but recently it became unusable, DCC constantly dropping out. It has loads of pickups, but a prod around under the hood showed that there was no circuit between one side (the left?) and the chip. I dismantled it and found that the pickups on the loco transfer current to studs, with no solder or anything - the pickup strip is sandwiched against the stud by the underframe moulding. I soldered some thin wire on and ran it round and up to the chip, that has fixed the problem.

My word, though, this is a fiddly blighter. If it was in a Haynes manual it would have five spanners and a bloody microscope. I am staggered that I seem to have managed it without bending the connecting rods or breaking the underframe mouldings. I guess it's worth it if the running is restored to normal, this loco drive model is worlds apart from the tender drive A3.

Guy

Reply to
Just zis Guy, you know?
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I have had the same problem with almost every model which uses this system. The idea of free pickups is sound but the locating method is a little random and the contact spigots through the chassis just a tad too short for comfort.

Regards

Reply to
Sailor

Hmm, time for a Comet models replacement chassis kit perhaps?

Nah, it would just have "This is a job for your Hornby dealer", such is the worth of the modern Haynes manual! :~(

I am

Anything is worlds apart from *any* tender drive unit, the best tender drive unit I ever came across was the old Trix unit (as fitted to their A4), but it's failings were apparent when used side by side with either the loco drive A1 or A3 from same stable...

Reply to
Jerry

On Fri, 2 Jan 2009 08:57:21 -0800 (PST), Sailor said in :

A monster swearing session was required to get the bloody contacts in place and correctly located fore and aft. But it runs really sweetly, smooth, quiet and fast. So I now have five dependable models: the A4, N2, 8F (my favourite), Class 110 DMU (but I am considering fitting a Black Beetle because I hate traction tyres) and the Class 08 shunter, which has exceptional slow-running marred only by a tendency to stop on points (an artifact of DCC, as I can usually restart it). I wonder if a sprung chassis would help with that.

Enough to play trains, anyway.

Guy

Reply to
Just zis Guy, you know?

But did you need to get into the fun with the pickup? And what period are you modelling :-)

Cheers, Simon

Reply to
simon

On Fri, 2 Jan 2009 23:56:46 -0000, "simon" said in :

Nineteen mumble to nineteen harrumph.

Guy

Reply to
Just zis Guy, you know?

You seem to want to blame all your problems on DCC! First the WLAN, now poor running over points.

If a loco stops, it's due to poor pickup which is in turn due to the loco or poor track.

Sorry, but it's not a DCC "artifact" at all.

MBQ

Reply to
manatbandq

Yep, sorry Guy but hes right.

Cheers, Simon

Reply to
simon

It is certainly a "pick up " problem but not necessarily the actual pick-ups! Several of my "loco only pickup " chassis fitted on 6 coupled models will do this at slow speed and especially on courved points and those involved in banked trackwork! This is due to my use of insul frog type points where two wheels can encounter the insulators simultaneously and the third wheel is not in contact with the rail. This is a perfectly normal situation which is usually overcome by flange contact ( engineering fact =3D no surface in contact with another, no matter how flat, will be in contact in more than three places). The addition of tender pick ups and or bogie/pony truck fittings also ensures better performance but is by no means foolproof. Flywheel motors have the advantage and Hornby tyre fitted locos (and mainline) are the most susceptible.

Reply to
Sailor

Can also be overcome with a brief spurt of extra power as John pointed out a while back locos - esp shunters - werent treated delicately :-)

Cheers, Simon

Cheers, Simon

Reply to
simon

So it's problem a problem with how the track has been laid - either lay your track flat (relative to the loco, not base board or horizon) or use sprung chassis, it's not the electrons fault that they can't get to were they should be!...

Reply to
Jerry

This is a perfectly normal situation which is usually overcome by flange contact ( engineering fact = no surface in contact with another, no matter how flat, will be in contact in more than three places).

Hmm. Not so, my boy. If you have sprung wheels on your loco all of them will be in contact with the rails. This is why P4 people (and even 00 people like me) habitually spring their locos. Also if you use low current basket wound motors (RG4s) you will find that the voltage drop at the rail/wheel interface is so low that you don't even have to clean your track. The 'toy train' manufacturers have ways to go to catch up on the technology now being used by finescale modellers. Hornby seem to have an inkling of the advantages of springing, as my new Black 5s have the rear set of drivers sprung.

Alistair Wright

5522 Models
Reply to
Alistair Wright

Of course they don't need to be sprung, just 'flexible', hence why Mike Sharman came up with his "Flixichas" idea - now only falling out of favour due to the wish to model inside cylinders etc... Once the basic (Flaxichas) principles are grasped it's a simple and (almost) fool proof method of keeping all the wheels in contact with the track.

Reply to
Jerry

Even double beam compensation provides sufficient flexibility for most of us. Our engines don't need to negotiate Mike Sharman's obstacle course.

Which was an amazing sight.

Reply to
Christopher A. Lee

Indeed, but it was just a demonstration to show the 'abuse' his system would put up with, of course one other advantage of his system was that it made all the wheel take a share of the total loco weight - thus problem wheel bases, such as 4-4-0, 0-4-2 and even 4-2-2 etc, would pull a respectable load without the need for extensive counter balancing or ballast-weights.

Reply to
Jerry

Oddly enough Alistair I have no argument with springing - in theory! In practice I find that the effort required is not rewarded by the results. The "sprung" Hornby models have all given me trouble no matter which model large or small. They all develop rear axle oscillations. I have just spent weeks fitting a 7 pole motor to an old Hornby M7 and might as well have built a new one from scratch. I am a member of the S4 society and stay au fait which the art but reserve the right to choose. Basically rtr has advantages over the "Engineering" approach ( I am an Engineer) which more than compensate for rivet counting/precise colour schemes etc to those of us who want more than a Station ( or dep=F4t) with fiddle yards so beloved of the scale fraternity. My expertese goes into the control of my system as being a solo operator it does not suit me to have failures on the track -- I do not have sufficient eyes or (at my age) the patience to pick up the pieces after the crash.

Regards

Reply to
Sailor

On Sat, 3 Jan 2009 02:48:52 -0800 (PST), " snipped-for-privacy@hotmail.com" said in :

DC works just fine over the same point. If you get a spike or drop, the DCC decoder (cheap ones, anyway) drop out and have to be given another input.

OK, so it is not solely due to DCC, but DCC makes it worse. Or so my empirical tests would indicate, anyway.

Guy

Reply to
Just zis Guy, you know?

"Alistair Wright" wrote

sprung.

Have you ever seen one of the Hornby Black 5s which sits absolutely level? I haven't (they sit slightly high at the cab end) and I've looked at loads of them since their release. Springing is fine providing it is done properly, but locomotives which do not sit level are not acceptable to me.

John.

Reply to
John Turner

"Jerry" wrote

And this Hornby dealer would say it's a job for Hornby's Service Department.

John.

Reply to
John Turner

If you have spikes confucing the decoder then there's a serious electrical problem, maybe momentary shorts caused by poor decoder installation, or poor power distribution.

If the decoder in the loco sees a power or signal dropout then it's simply not picking up properly.

The decoder will "be given another input" as soon as the rail/wheels/ pickup give contact again. DCC commands are repeated constantly, even with no further input from the throttle.

MBQ

Reply to
manatbandq

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