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Keep Alive/ Stay Alive decoders

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Have you checked the voltage of your dcc system (ie take a reading between the blue and white wires of a loco fitted decoder) - DCC Concepts are using 16v caps so the cap could have failed if the voltage is higher (Multimaus users with a Roco supply beware unless you have dropped the voltage).

 

No, I didn't think it necessary. I have a wide selection of controllers (Bachmann EZ command, Hornby Select, Hornby Elite and NCE Power Cab). None of which has thrown any Bachmann, TCS, Hornby (well, except one), CT Electronic or Digitrax N or OO decoder into a failure state in our house.

 

As such, I'd suspect the DCC Concepts end of things.

 

 

I must say I'm also disappointed with the 'stay alive' on the DCC concepts decoder. I've ordered one of the TSC decoders with the KA1 stay alive to try out. At least TSC make some claim as to the effectiveness of the device (2-6 seconds) so should be easy to see if it's working. No such claims by DCC Concepts so who knows what to expect.

Might be worth giving the TCS KA1 a try on the DCC Concepts decoder.

 

Aye, but how to connect it without a puff of smoke ?!

Edited by dave flint

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My experience is that 16V is marginal at best. I have had cheapo caps get very hot and fail very quickly.

 

22V is much safer, as the rectified supply on my Lenz Compact is pushing 17V.

 

I have some nice 22V 1800uF Panasonic caps that are a good size and very reliable.

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TCS Decoder (DP2X-UK-KA) and Keep Alive (KA1) arrived today. Just performed a quick test in my ESU decoder tester board and the motor was still running 10 seconds after removing power (speed step 10 of 128). Impressive, does just what it says on the tin (better in fact). Admittedly more expensive than the DCC Concepts offering but like Olddudders said earlier in this thread, 'you pay's you're money'. It's still considerably cheaper than the Lenz Gold/UPS combination. Will install in Sentinel over the weekend.

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Aye, but how to connect it without a puff of smoke ?!

 

The same as the DCC Concepts one - blue wires together and whatever colour the other wires are together (on the direct plug in DCC decoder it is black, while TCS use black/white)

Edited by Butler Henderson

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The same as the DCC Concepts one - blue wires together and whatever colour the other wires are together (on the direct plug in DCC decoder it is black, while TCS use black/white)

 

I was going to guess that would be the case. The only thing stopping me trying the KA1 with the DCC Conceprts decoder at present is knowing whether their is a charge limit resistor and discharge diode in the TSC unit. It's not clear without cutting the heat shrink off. Their does seem to be four surface mounts components on the PCB under the heat shrink in addition to (what I presume is) the six capacitors.

Edited by tender

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A pretty shameless bump for this topic. Has anyone wired up a DCC Concepts decoder with a TCS stay alive yet ?

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A pretty shameless bump for this topic. Has anyone wired up a DCC Concepts decoder with a TCS stay alive yet ?

Another TCS KA1 should be arriving in the post today, will connect to DCC Concepts decoder tonight and report back.

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A pretty shameless bump for this topic. Has anyone wired up a DCC Concepts decoder with a TCS stay alive yet ?

 

It won't work, I'm told by TCS, as there is additional software installed which needs to match up. The DCC Concepts stay alive will work with TCS decoders, though.

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It won't work, I'm told by TCS, as there is additional software installed which needs to match up. The DCC Concepts stay alive will work with TCS decoders, though.

 

Yep, John is correct on this. Connected up the KA1 to the DCC Concepts decoder and while it worked ok while power was supplied to the track, the motor took off like a rocket as soon as power was removed (for a second or two).

With the TCS/KA1 power can be removed (for a second or so) and reapplied with negligible effect on the speed of the motor.

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Grrrrr ! That's just typical. Ok, for a numpty like me, could someone please suggest a little circuit I could wire in to make a better stay alive using the existing DCC concepts decoders two wires - ie no soldering on the chip ?

 

I'd like to know if anybody gets this out of a DCC concepts decoder (2 seconds), mine stops as soon as all wheels are on the tape. At best I would think it's in the order of milliseconds if that. Unless my stay alive has died!!!

 

Ray

 

Agree. I would put a decimal point in there - 0.2 seconds more like it.

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Hard to do it on decoders without the NMRA black/white wire - that is why you have to do the soldering. The new DCC concepts decoders have the wire (although I don't think it is the correct colour).

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But thats it. I have quite a few DCC Concepts ones with a blue and black wire for the stay alive. I know that their stay alive has a little PCB on it that obviously does something. (you just can't connect a capacitor to the wires). I was wondering if someone could advise what that circuit did, and possibly guide a numpty like me to make up a similar device but with a much bigger cap that would connect to the blue and black wires..

 

I can solder a decoder into a loco, and make up something like this, but soldering onto a decoder is beyond my capabilities, and my knowledge of electronics in general is shamefully poor.

 

To me, the DCC Concepts decoders are a step in the right direction, but the stay alive bit is woefully insufficient as supplied. I would have happily bought some of these TCS stay alive to use with them, but that has been proved to be a non runner. Ditching the decoders that I've installed for new TCS and stay alives is not feasible.

Edited by dave flint

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I'd like to know if anybody gets this out of a DCC concepts decoder (2 seconds), mine stops as soon as all wheels are on the tape. At best I would think it's in the order of milliseconds if that.

Agree. I would put a decimal point in there - 0.2 seconds more like it.

 

Forgive me if I've got it wrong guy's (the memory is fuzzy and I can't be a**ed to look it up)..........., but I'm sure Richard Johnson of DCC Concepts has said, that his application of Stay Alive is more to do with smoothing out the power supply over momentary interruptions, rather than to provide power for more than a second or two.

If that's the case, then it would indicate to me that the DCC Concepts, TCS and Lenz implementations are all different in character, if not the purpose they are intended for.

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The circuit is simple, choose your capacitor (the bigger the better but rated at 35V) and connect the negative end to the black/white wire (the black one on the DCC concepts decoder) and connect a resistor (chosen to limit the maximum charging current, 20R should be OK to keep the current below 1A, but you might want to increase that if you have a lot of locos on the layout) between the blue wire and the positive of the capacitor. Connect a low voltage drop (UF4001 should be cheap enough) discharge diode across the resistor with its cathode (stripe end) connected to the blue wire. It is that simple.

 

Running time will be dependent on how much current your motor takes and on throttle setting and on whether the decoder performs well under varying supply voltage conditions, You are only going to get a small amount of power out of the capacitor so you will need a big one. If you do not have room go for the Lenz solution.

 

Using this method I find that 35V 4700uF is completely effective in a Lima loco with four wheel pickups - if you have dead frogs you will need something a lot bigger. It is not about how long the capacitor will provide power for at full throttle, it is about providing sufficient power while the loco gets by a speck of dirt at low speed (and ensuring that there is starting power if the loco is stopped on dirt if your decoder will still decode the data on dirty track).

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The information has been posted on the forum many times, but here's a snip from the webpage that helped me add Stay Alives to Lenz Standard chips

 

post-6717-0-01161600-1331814552.jpg

 

No need for a PCB etc, solder the resitor and diode leads to the + of the cap and the blue wire, the black wire from the decoder (NOT THE TRACK FEED BLACK WIRE) to the - of the cap

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I would say that 35V is a bit high. 25V ones are fine for most DCC system in my experience. My Lenz gives 17V across the rectifier on the chips. Just to high for 16V, but safe for 25V. Buy good quality capacitors for good long life. I found some nice little Panasonic 1800uF that are compact and easy to hide in a cab or tender.

 

The Lenz stay alive uses a 2.7V super capacitor of better than 2 Farads linked to a voltage multiplier to give an output of 12V or so. This is a much more efficient way of storing energy.

 

My own design follows the Lenz, but with cheaper 1F 5V capacitors linked to a voltage multiplier, giving 200mA @ 9V. It is good for about 2 seconds at low throttle on a Tenshodo Spud.

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Thank you all, just what I needed (sorry for being a bit dense). I'll peruse the Maplins website and get a few bits sorted out now I know what to do.

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My own design follows the Lenz, but with cheaper 1F 5V capacitors linked to a voltage multiplier, giving 200mA @ 9V. It is good for about 2 seconds at low throttle on a Tenshodo Spud.

Can I ask what decoder you're using with your DIY circuit?

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And another one from me I'm afraid....where do you buy your components from ? Maplins website has very little listed, RS components have a bewildering array.....

 

I've bought stuff from maplin shops in the past, but for a large order I thought online would be easier.

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I bought my first test components from Maplins, but we have a shop in Mansfield ;) for bulk buys I find Rapid blow Maplins out of the water on price

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My circuit is currently wired onto a cheap and cheerful Hornby basic decoder. I was not going to risk trashing anything expensive.

 

A good source for components is www.cpc.co.uk Worth getting a larger order together to avoid postage costs etc.

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for bulk buys I find Rapid blow Maplins out of the water on price

Bit of a difference between a High St retailer, with all those overheads and what is basically a trade warehouse methinks.

If I want any serious electronic components I usually go to Rapid. I find Maplin don't stock much these days.

I wanted 4 diodes the other day and was flabbergasted when I was told that the shops only stock a maximum of 2! However there is no delivery cost if they are ordered and collected from the shop.

 

Keith

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Found an electronics shop on my travels, and managed to gets some bits for a trial fitting. Managed to get a 2200uf cap into bachmanns Percy, and its made a huge difference. Not perfect, but only a crawl over insulfrog points will sometimes stop it now.

 

The loco still stops though before restarting, so its not the most "transparent" switch between track and cap supply. I admit defeat in the much smaller vachmann bill and Ben, so think that the tcs solution might be used.

 

But good results so far, and thanks for everyone's help.

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A number of suppliers of electronic components can be found on ebay - useful if you just want a few bits which fail to meet the minimum order level of mail order suppliers or their P&P is prohibitive. How essential is the 100 ohm resistor being a 1/2 watt - just have a number of 1/3 or 1/4 watt ones and looking at the surface mount ones DCC Concepts use I doubt they handle much.

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