96RAF Posted April 2 Share Posted April 2 Can I just point out an error in the current HM7K decoder manual. It presently states '....there are C- and C+ pads on the decoder ..... and that charging components are present on the decoder....' It should say that there are NO charging components on the decoder. There are built into the power bank only and the transistor that controls the charging process by way of these additional components is triggered by the MCU on the decoder after a delay. The manual will obviously be corrected but it should be noted that the use of any 3rd party stay alive that does not have integral charging control components are definitely not suitable no matter what plug is fitted or how the connections are made. Link to comment Share on other sites More sharing options...
ColinB Posted April 2 Share Posted April 2 1 hour ago, 96RAF said: Can I just point out an error in the current HM7K decoder manual. It presently states '....there are C- and C+ pads on the decoder ..... and that charging components are present on the decoder....' It should say that there are NO charging components on the decoder. There are built into the power bank only and the transistor that controls the charging process by way of these additional components is triggered by the MCU on the decoder after a delay. The manual will obviously be corrected but it should be noted that the use of any 3rd party stay alive that does not have integral charging control components are definitely not suitable no matter what plug is fitted or how the connections are made. I understand that there are no charging components on the decoder but are you saying that the transistor that controls the charging is on the decoder pcb? Link to comment Share on other sites More sharing options...
96RAF Posted April 2 Share Posted April 2 2 hours ago, ColinB said: I understand that there are no charging components on the decoder but are you saying that the transistor that controls the charging is on the decoder pcb? No - as stated the transistor is part of the PB and is triggered by a bias voltage from the decoder MCU. Link to comment Share on other sites More sharing options...
ColinB Posted April 2 Share Posted April 2 3 hours ago, 96RAF said: No - as stated the transistor is part of the PB and is triggered by a bias voltage from the decoder MCU. Great thanks that is how I suspected it worked. The decoder I also assume contains the diode that feeds VRef when the "stay alive" is in operation. 1 Link to comment Share on other sites More sharing options...
Daedalus Posted April 2 Share Posted April 2 I confused! Is it an open collector output on the decoder? Link to comment Share on other sites More sharing options...
ColinB Posted April 2 Share Posted April 2 Just now, Daedalus said: I confused! Is it an open collector output on the decoder? I know I have racked my brain with all the electronics knowledge I have learn over the years and it doesn't make sense. To control a transistor on the powerbank you need a separate input. The Powerbank only has two, you would need three to make it work. Link to comment Share on other sites More sharing options...
Daedalus Posted April 2 Share Posted April 2 Yes we seem to have quantum transistors that are on the decoder or XOR in the power bank simultaneously🙂 Link to comment Share on other sites More sharing options...
96RAF Posted April 3 Share Posted April 3 I will leave you guys to work it out. I will stick with the wiring diagrams that I hold under NDA. I have told you as much as I can without publishing a schematic. It's all academic anyhow, the Hornby one works as advertised and 3rd party ones may or may not, depending upon the smarts of their designers. As advised use them at your risk to warranty support. Link to comment Share on other sites More sharing options...
ColinB Posted April 3 Share Posted April 3 Of course it works, they wouldn't sell it if it didn't but given the description I suspect not as described. This is my last comment on this as I just think it is not all that it is made out to be. Normal "stay alive" has two connections which normally would go to VRef and Ground, so if there is no logic on the decoder Powerbank must have the same, so unless you have some supporting logic on the decoder which connects to Vref there is no way you can control the charging current with a port on the decoder. As I say they work, so that is it. I did read a lot about all different ways you could implement "stay alive" by using voltage doublers as in the case of the Train o Matic ones (looking at the components on a LaisDCC pcb they don't do it this way). So I will leave it at that. Link to comment Share on other sites More sharing options...
96RAF Posted April 3 Share Posted April 3 40 minutes ago, ColinB said: implement "stay alive" by using voltage doublers as in the case of the Train o Matic ones (looking at the components on a LaisDCC pcb they don't do it this way). I thought you said they did in another thread that I can't find. Link to comment Share on other sites More sharing options...
ColinB Posted April 3 Share Posted April 3 13 minutes ago, 96RAF said: I thought you said they did in another thread that I can't find. No someone else said that, probably why you can't find it, I thought they were wrong but I just thought I didn't want to correct them. I am pretty sure on the LaisDCC Kung Fu ones I use, they don't, as they use 4 capacitors and on the one of mine where the wires fell off there was no voltage doubler device (it needs more than 3 pins). By using ordinary capacitors that is how they can sell 5 different sizes. Also if they used a voltage doubler device they would be more expensive than what I pay. Looking at the PCBs Train O Matic use them, as do Zimo on their more expensive "Stay Alives". Link to comment Share on other sites More sharing options...
Fishmanoz Posted April 3 Share Posted April 3 Pretty sure it’s ateshci who mentioned voltage doublers and has used them with his custom PCB. Link to comment Share on other sites More sharing options...
ateshci Posted April 4 Share Posted April 4 It's not a voltage doubler, but a full-fledged step-up converter that delivers 10V from an input of 5...1.5V, because the capacitor delivers the needed energy and is discharged therefore. The components on the decoder are a transistor to switch the charging current on/off ( I'm not sure whether it can handle more than 50mA ) and a reverse bypass diode into the motor/electronics supply to provide energy in case of contact loss. Link to comment Share on other sites More sharing options...
Fishmanoz Posted April 4 Share Posted April 4 My mistake. Link to comment Share on other sites More sharing options...
ColinB Posted April 4 Share Posted April 4 7 hours ago, ateshci said: It's not a voltage doubler, but a full-fledged step-up converter that delivers 10V from an input of 5...1.5V, because the capacitor delivers the needed energy and is discharged therefore. The components on the decoder are a transistor to switch the charging current on/off ( I'm not sure whether it can handle more than 50mA ) and a reverse bypass diode into the motor/electronics supply to provide energy in case of contact loss. I called it a voltage doubler because that seemed an easier description. Ii is a switched mode integrated circuit that does the necessary conversion in this case stepping the voltage up from the stored value on the capacitor. Actually from your description it is a voltage doubler because fully charged the charged voltage will be 5 volts. Link to comment Share on other sites More sharing options...
Wayne-742734 Posted May 2 Share Posted May 2 Can somebody advise the name of the 3 pin plug so i can buy some please , i have soldered a Lais DCC stay alive on to a 8 pin HM7000 it works fine no issues but need to try make up some for my 21 pin decoders please advise . Wayne Bridgman Link to comment Share on other sites More sharing options...
96RAF Posted May 2 Share Posted May 2 2 minutes ago, Wayne-742734 said: Can somebody advise the name of the 3 pin plug so i can buy some please , i have soldered a Lais DCC stay alive on to a 8 pin HM7000 it works fine no issues but need to try make up some for my 21 pin decoders please advise . Wayne Bridgman Previously covered on the forum with a datasheet. Link to comment Share on other sites More sharing options...
SteveM6 Posted May 2 Share Posted May 2 44 minutes ago, 96RAF said: Previously covered on the forum with a datasheet. And with a caveat that the components are so small, manual assembly would be nigh on impossible. 1 Link to comment Share on other sites More sharing options...
Pendragon Sailing Posted May 2 Share Posted May 2 10 hours ago, Wayne-742734 said: Can somebody advise the name of the 3 pin plug so i can buy some please , i have soldered a Lais DCC stay alive on to a 8 pin HM7000 it works fine no issues but need to try make up some for my 21 pin decoders please advise . Wayne Bridgman As an experiment, I tried to retro-fit one of the tiny plugs, and found it impossible. The connections are so minute there are no tools (or eyesight) that I know of that would allow you to do it at home. If you want to avoid soldering directly to the 21 Pin decoder, all you can do is to wait for Hornby’s PB supply chain to free up again. Alternatively, if you can get your hands on some suitable plugs that have already been wired (good luck there), you could then just solder them on to your Lais Stay-Alive’s wires. Not very helpful, I know. But there it is 🫤 Link to comment Share on other sites More sharing options...
Loewietje Posted May 2 Share Posted May 2 For the moment, I have no need for a non-Hornby Stay-alive, but if my small stock runs out before new ones appear, and I can find a EU retailer who sells them, I will try a DCC-concepts one. But with clean track, and 8 or more pick-ups no troubles so far. Only my A5 so far needs one, and possibly my Y1, J50’s and J70, but these aren’t on the roster yet. Link to comment Share on other sites More sharing options...
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