Pickups [when converting to DCC]

[Chris-K]

Hi, this might sound daft but can someone explain to me what this means, I'm looking at adding dcc decoder to an old HST 125 intercity train and reading up on how to hard wire it in etc someone mentions I could wire it so that it had pickups from front and back bogies on the power car, all on the same side, is it worth doing this or not and just leaving it with the original pickups, I don't understand what it means by pickup either?

Any help would be appreciated

Thanks

[ColinB]

Pickups are the means by which the loco "picks up" power from the track, normally wipers (small pieces of copper) that touch the wheels. Now there was a time when Hornby used the axles to pick up the power as is the case with your loco. On the front bogie the wheels on one side are solid, the wheels on the other side have insulators. On the other bogie the arrangement is swapped round. So the chassis of the power bogie is connected to one rail and the non driven bogie is connected to the other. Now this works ok if your track is perfectly clean and you don't go slowly over points, as all the wheels have to make contact. To make the loco run better what you can do is ad pickups to both wheels on the non powered bogie by either buying the pickup piece from a later Ringfield based HST although they are difficult to come by, or buy the pickup piece from a class 90 and shorten it. The pickup piece clips onto the bogie and obviously you will have to change the wiring but it makes running a bit more reliable. On the later Ringfield motored bogies they did add pickups to both sides, but in reality because of the traction tyres it doesn't improve running that much.

[Rog RJ]

The pickups on most Hornby models are thin phosphor bronze (looks quite like brass) strips that press on the back of the wheels to transfer power through the wiring to the motor.

[Chris-K]

Thanks for the information, this is what I have read if that makes more sense, just unsure if to do it or not as will it improve the performance or not:

At the rear end two wires come up from the unpowered bogie. The longer brown wire had its far end removed from the motors right-hand strip. Now make an in-line soldered joint to the decoders Red wire with this wire.

The other wire from the rear bogie which is shorted and runs to the lamp is reused.

Its removed from the bogie connection and then its brought back into the loco. It is then connected as an in-line soldered joint to the decoders White wire. Note there is a second option with this wire where its left connected to the bogie and cut inside the loco. The short length running to the lamps still connects to the decoders White wire. The piece of wire coming up from the bogie is then extended and the far end of this extended wire is connected to the Red wire joint at the front end. This would then allow wheel pick up from one front wheel (the motor bogie) and both same side rear wheels. But the choice is yours.

[Will Hay]

Having converted quite a few older DC models to DCC, I've found that many just don't run as well on digital as they do an analogue.

DCC is less forgiving than DC and before replacing most of my creations with better, newer, DCC ready versions, extra pickups would have helped.

However, at the time, I didn't have the skillset.

Instead, I fitted a stay-alive to my [compatible] decoders which proved successful.

[Chris-K]

Thanks Will, are you suggesting that I should go with the extra pickups then, also how would the stay alive help the performance.

Thanks.

[ColinB]

The extra pickups definitely improves things before you add "stay alive". If lets say you convert your HST, if you are crossing points and the not powered bogie transverses the plastic frog of the point, so it doesn't pickup power. The power bogie can only get current from the one set of wheels, so normally the loco would stall, but "stay alive" might give you an extra second of power which might be enough time to transverse the point. On the old style of locos I have, and my converted 1980s HST, I added extra pickups to the non powered bogie and added "stay alive". They will never be as good as a modern loco, but will be substantially better than they were.

[Will Hay]

I'm afraid I've never fitted extra pick-ups.

I can only confirm that the brief and random 'stuttering' I experienced having converted older, DC models to DCC, something I put down to a lack of constant power due to pickups to, for example, only fitted to one bogie, was cured by fitting a stay-alive.

None of my modern, DCC ready locomotives suffered the same issue as *some* of my DC > DCC conversions, all of which were converted in the same manner.

As a couple of folk will invetibably and very shortly attest to, I'm far from an expert, I can only contribute from my own experience and trust it might help 👍

[Chris-K]

@ColinB

The extra pickups definitely improves things before you add "stay alive"............

 

 

Thanks for the information, very helpful would you say I should do both then, do the extra pickups and also the stay alive? I have the 1990s high speed set

Thanks

[Will Hay]

As I touched on in my initial post, I would have fitted extra pickups had I the skill at the time, this would have been my preference and as Colin has stated, is the better option.

Converting to DCC was me at my peak, given that anything that travels down a wire is clearly witchcraft 😄

Edit.

Just to pick up on one point, stay alive gives you much more than a brief second of extra power, I have two types, a six second push [when that's all that was in stock] and a three second type.

They're very effective but some people seem to favour a laborious process of identifying the root cause, which is fine, for them.

[37lover]

Will Hay,

My very basic knowledge of Stay Alives suggest a six second push would be a huge component, and for that matter also a three second one. Would you please be so kind as to post further details.

[Chris-K]

I've also learnt and been told that stay alive will not work with the Hornby select controller is that correct?

[Fishmanoz]

Most definitely not correct. The Select cannot tell whether a decoder has a stay-alive fitted or not. It’s operation is entirely within the decoder where the charge held in its capacitor holds up the decoder rail voltage, keeping the decoder operating until that capacitor discharges.

For some or all of that time, the controller isn’t even connected to the decoder, the point of having a stay-alive in the first place.

P.S. could a mod move this thread to the DCC section where all the DCC people will be able to see it.

[Will Hay]

I only used the select for a very short period, before I switched to a non-Hornby controller.

I can't think of any reason why the select wouldn't like a non-Hornby* decoder with a stay-alive fitted.

*Hornby don't make a decoder with a stay-alive function.

[ColinB]

"Stay alive" is just the act of putting a capacitor across the regulated DC supply that the DCC decoder generates internally ( I could get into the technical but I will keep it simple). This is what feeds the motor, so effectively powers it if there is no input voltage. In my initial post I said about a second of power. To be quite honest I think this is probably an exaggeration on my part, it depends on the capacitor used and the motor current. "Stay alive" causes issues with a DCC controller not just the Select. It shows itself in not being able to read values out of the decoder, caused by the programming voltage not being fed to the decoder for long enough to charge the capacitor fully. As the capacitor is not fully charged, then the decoder's supply is not at its proper value, so the decoder does not function properly in programming mode.

[Will Hay]

@37Lover

My very basic knowledge of Stay Alives................ Would you please be so kind as to post further details.

 

 

From the manufacturers eBay advert...

"...The Stay Alive device we supply will power an HO/OO locomotive for approximately 6 to 20 seconds depending on the locomotive, and efficiency of the motor".

My six and three second quote is based on memory of the ebay advert at the time, from the two sizes I used successfully.

My first use was of two, six second versions, fitted within a Hornby Railroad Tornado [fitted in tender] and a Hornby Evening Star 9F [fitted in the locomotive].

I only reverted to the 3sec [medium] option as the 6sec was a bit of a squeeze [hence why one went in the tender, the other went in fine in the Evening Star] and I couldn't get hold of the smaller option at the time.

Six seconds is definitely overkill, I'd say a second would be sufficient.

The brand is LaisDCC, of which I've seen many negative comments.

All worked absolutely fine for me.

I'd guess I have about ten fitted within the thirty-eight locomotives I have, and have *never* had a problem that wasn't of my own making.

The one criticism I do have is that they're not as well made as my Hornby, Bachmann etc. decoders but at circa. half the price and in my opinion, it's to be expected.

I don't know what you class as small but these stay-alive components, soldered to the trailing wires supplied with the decoder, are quite small in my opinion.

If I can fit them in a Hornby steam locomotive, they must be.

EDIT.

The sizes I have are 27x11x8 and 25x9x7.

These are classed as large and medium.

There are a further two available; small and very small.

These are obviously smaller than the sizes I've listed.

In the unlikely event that I need anymore I'll go for the smaller size.

I hope that helps you 👍

[Will Hay]

Oh, and I should add that I have tested the stay-alive using the 'kill switch' and reckon my two types sit around the four and two seconds mark, before they stop [rock and] rollin'.

[Chris-K]

This is what I have been told by a company wanting to fit the decoder and stay alive for me.

"It is the LAISDCC kungfu decoder with stay alive function which keeps the train powered for up to 10 seconds with out power great for smaller wheel based locos which may stop when travelling over points. (This can’t be used with any Hornby DCC controller due to compatability issues) the signal from the controller is slightly different and just will not communicate with chip. It’s something Hornby know about but have never done anything about it."

[96RAF]

@chris-k

Not wishing to shoot the messenger but . . .

The Elite is NMRA certified, not just compliant, Early Selects were non-compliant, but only due to ringing on the signal under no load or light load conditions. Planting a few locos on track damps out the ringing.

I would suggest that it may be the knock off Liais decoder that is the problem. A stay alive (bottom of picture) should not affect the DCC signal as it is simply a ‘battery’ that fills in for any glitch in the track power getting to the loco. The loco will obey the last command until the signal is restored.

[Chris-K]

My select came with the mixed freight digital set, Is there away I can find out what the firmware is and can this be updated also?

Thanks

[Chrissaf]

Chris-K

It has been pointed out in replies to your posts more than once that using the blue button with the white arrow is not the best way to reply. This time you used the blue button on Rob's image post which sent your reply attempt back to the image approval queue. It has now been approved in an edited form and shows above.

It is so much more efficient to use the preferred reply method by writing your reply in the "Reply Text Box" at the bottom of the page and clicking the green 'Reply' button.

To answer your question, Yes the Select firmware can be updated. The current installed firmware is the very first number to briefly appear on screen as you power up the Select. This firmware number will be between 10 & 20 and be followed by the number 30 then the number 03.

[Chris-K]

Is it recommended to use or stay alive or not on converted train, just interested whether people think it's a no brainer to do or not

Thanks.

[Chrissaf]

Although I have had no need to add any "stay alive" to my own locos. I do feel that if someone is installing their own decoders, then it is worthwhile adding even a small 'stay alive', whilst taking advantage of the loco being already dismantled for the decoder installation task.

At the top of the "Hornby DCC" forum is a sticky thread titled "Hornby DCC FAQ Index". I wrote FAQ 2 in this thread describing how to fit a 'stay alive' to decoders that were not factory designed for them. This is worth reading, even if only read as background information.

See also my reply to your other "LAISDCC kungfu" thread.

[Will Hay]

@Chris-K

 

 

On one side you will have people say your system shouldn't need them.

On the other side you have people like me who prefer to play more than they work so, in my opinion and certainly on the older models, it's worthwhile.

[Chris-K]

Thanks, I agree I've also read that altering CV29 to disable DC is recommended and something about changing CV11? Is that something you have done or recommend as well.