#40 Part 2: Fitting a Stay Alive Capacitor Unit to a Hornby TTS Sound Decoder

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This is Part 2 of an in-depth two-part series looking at home-made stay alive devices. In this video, we look at adding a stay alive/keep alive unit to Hornby’s TTS sound decoder.

If you wished to add a stay alive unit to Hornby’s R8249 decoder, the steps would be similar (although the negative leg would have to be soldered directly to the negative side of the rectifier).

We made the stay alive unit in the previous video (Part 1 – Making a Stay Alive Capacitor Unit), and if you’ve not seen that video, you can watch it here: https://youtu.be/S2BmPiurl-0

Please note: the steps covered in this video do require a steady hand and competence with a soldering iron. Working with DCC decoders and tiny surface-mount components leaves little margin for error and it is very easy to permanently damage sensitive electronics if you are not extremely careful.

+ Video Contents +

00:00 – Introduction
00:20 – A quick recap
01:20 – Examining the decoder
06:08 – Soldering it all together
14:52 – Testing the solder work
16:10 – Fitting it all into the chassis
18:05 – A word about CV settings
19:08 – Testing the stay alive unit
20:53 – Conclusions

+ Components +

You can buy items used in this video tutorial using the affiliate links below. Using these links helps to support the channel and is very much appreciated.

Hornby TTS decoders (Amazon): https://amzn.to/2PbRM9x
Hornby TTS sound decoders (eBay): https://ebay.to/2S1P4Ca
Capacitors (15,000 uF 25v): https://ebay.to/2AljFnF
Resistors (100 ohm 1/4w): https://amzn.to/2yzLtDx
Decoder wire (red & black): https://ebay.to/2NR9fj1
Decoder wire (Multipack): https://ebay.to/2PGEYoK
Diodes (1N4001 50v 1A): https://ebay.to/2CXBifB
Diodes (1N4001 50v 1A):: https://amzn.to/2ODFqYo
Heat Shrink (multipack): https://amzn.to/2PdO0N5
Heat Shrink (various sizes): https://ebay.to/2EvWI54
Kapton tape (10mm x 30m): https://amzn.to/2OBEpjB
Kapton tape (various sizes): https://ebay.to/2R2H2aU
Liquid Flux Topnik No Clean (Amazon): https://amzn.to/2Al6HpP
Liquid Flux Topnik No Clean (eBay): https://ebay.to/2CXy7EO
0.3mm Lead/Tin solder: https://amzn.to/2NT7pOy
0.3mm Lead/Tin solder: https://ebay.to/2S6Jpe0
Hakko Soldering Station: https://amzn.to/2CVLzca
Blue silicone electronics mat: https://amzn.to/2Pbv7ug
A2 green cutting mat: https://amzn.to/2P8aKy3
A1 green cutting matt: https://amzn.to/2P8aKy3

#StrathpefferJunction #HornbyTTS #StayAlive #KeepAlive

Thank you very much for watching.

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Visit us at: http://www.strathpefferjunction.com

+ Disclaimer +

This project does require a steady hand and competence with a soldering iron. Working with DCC decoders and tiny surface-mount components leaves little margin for error and it is very easy to permanently damage sensitive electronics if you are not very careful. If you choose to follow any of the steps or suggestions outlined in the video, you do so at your own risk and any damage or injury to yourself, your models, your equipment or others is your own responsibility.

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Cottesmore says:

Thanks for both videos, very helpful ? it’s my next to do for DCC Sound

TimberSurf says:

Very professional presentation ?well presented and great list of links 🙂

N Gauge England -Synthematix- says:

For the price of trains in N and OO gauge trains, stay alive capacitors should already be fitted!

Simon -Liverton Central says:

Very nice second video David.

Melanie Rhianna says:

I never use flux when soldering electronics. A good rosin cored solder should be good enough. As for the pins, the blue common makes sense since this will be the 5V rail. DCC decoders have active ground on their function pins. So finding ground is the difficult bit but you've already done that 🙂

Terry Love says:

Another great video but I do not see why you did not put it across the incoming DCC pair?

John Witchard says:

A good pair of videos and solution to a quandary I have had for a while. A while ago I watched a Phil Downs video about stay alive capacitors. His solution from the comments was the positive going to the blue wire and the negative going to the negative wire of the speaker, either soldered to the decoder end or the other end depending how confident you are with your soldering. I just thought I would mention this for viewer who weren't to confident with their soldering. Thanks again for your great videos.

Onno Mulder says:

Good instruction videos!! Thanks Onno.

John Brush says:

Another good video David. A quick suggestion, which to be honest may not be worth much as you still need to solder the negative directly to the chip, but its one less risk of getting big blobs of solder all over the decoder 😉
The positive could be soldered directly into the blue wire (cut and rejoin or possibly just scrape a small bit of insulation off the wire with a sharp blade) or if its a DCC ready loco, onto the blue pin pad on the DCC socket.

alan margalan says:

Another brilliant helpful vidio David, I start doing one tomorrow morning, I asked you if it was possible and it surely is thanks for the download it was really helpful. Regards Alan…………

Finnerton central model railway says:

Wow I would never do that that’s way too technical for me lol

Creeping Jane says:

Thanks for that, another job to be done n times! I do have mixed feelings about stay alive as it can mask other problems. A cautionary note though, be careful when using a bleeping/buzzing continuity tester, you are introducing a voltage that could blow some components on your decoder if you put the prods in the wrong place. It would be better to set it to measuring resistance. The audio is very helpful rather than having to divert your eyes from what you are testing, but potentially you could ruin what you are testing.

Ian Huxstep says:

Great video, thanks. Is that a home made test track or purchased, If home made have you done a youtube video on its construction?,

paul m says:

Good video informative. the blue tack is a excellent tip The blue is a common return thus soldering to the blue wire negates the need to solder on to the chip. Good tutorial.
very well explained.

richierex says:

You tend to use a lot of solder on your joints, also have you tried cored solder or is that too thick? Nice job though

Bob Fuller says:

I'm currently having a Strathpeffer Junction video binge and thoroughly enjoying the videos.

Just a note about Kapton tape…it is in fact a very effective heat insulator. It was originally developed as a heat shield for spacecraft. So if an electronic device is completely covered in Kapton tape it will not be able to dissipate heat. This could then cause the device to overheat and fail.

jake atkinson says:

I’ve got a Zen chip and stay alive which works brilliantly apart from the fact it zooms off when the stay alive kicks in. Any idea how I can stop it doing that, guess it’ll be the CV settings?

jan kochanowski says:

Hi! On one of your videos I have seen you using Roco/Fleischmann Multimaus to operate DCC. I wont to buy z21start (white box) witch Multimaus. Since it is a German product I am wondering how will it cooperate with decoders like ZN6D ZEN 6-pin, Hornby X9659 4-pin, Hattons Originals DCR-6PIN, Gaugemaster DCC23 6-pin. Can you give me any hind? If z21start will be not available my plan B is to buy Gaugemaster DCC01 Prodigy Express.

RC Cosplay says:

Great instructional video. Finally can make sense of it all as I've purchased a T4 for a soundtraxx economy. @ least now I know "bridge rectifier" thanx… ?

Robert Pinch says:

Great video thanks a lot. Just one question did you get the diagrams available for download and where are they?Kind Regards Robert

Jtag Sheep says:

Thanks for the tutorial both parts ! I have fitted a 2 cap stay alive to my Hornby jinty 0-6-0 and while my electrolytic caps are only a combined total of 1000 micro farad wich is no where near enough to keep the train alive for a second I have noticed that running at slow speeds has improved significantly. What makes this test even better is the fact I pulled out a dirty old piece of flex track from under the bed that needs a good clean and she crawls nicely at slow speeds ! I will however be replacing the two caps with some super or ultra caps with a higher uF rating to provide a better experience !

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