Keep Alive for Paragon 3 sound decoder?

[Steveruger45]

Hi Otto,
I’ve been following this thread with interest.  So it appears you wire your keep alive across that capacitor on the decoder. I can’t see which side is positive and which is negative on that photo but assume you have that info.
Then you would solder the positive of your keep alive to the positive of the onboard cap and vis versa for the negative.
Use the Hako you have with the finest chisel tip you can get and some good quality fine solder.
I use Kester “44” 63/37 x 0.020” solder but you can also get 0.015”, which might be a bit easier on real fine work. This solder is USA made good quality stuff with a 3.3% flux core.  You can get it online in small quantity handy sized tubes from CMLSupply.com
What I do on the ESU 73199 decoder, which I have also used the caps onboard as the attachment points, is set my Weller to 750F and using the finest chisel point tip, I tin the tip, the wire and the cap I’m attaching to on the decoder
Set the soldering temp to about 750.
Once tinned just place the wire onto the cap and rest your iron on it for a couple of seconds and that’s it.
Good luck

[MK]

I can’t see which side is positive and which is negative on that photo but assume you have that info.

Steve, it's labeled in the decoder picture but it's hard to see.  You see a "Capacitor -" and "Capacitor +" in the picture.

[Steveruger45]

Ah, thanks, I see it now. My eyesight is not great.
Oh yes I forgot to mention Otto that I tape my decoders down on a block of 1x3 wood with painters tape to stop it moving about.

[peteski]

I'm surprised at the hookup location. I would have expected  it to be on the other side, at the bank of the 6 tan-colored capacitors.

[Cajonpassfan]

John, Steve, thank you for the soldering tips, very helpful and appreciated. I might need to get some supplies before I tackle this.
Pete, I too was surprised at the location. I just hope it’s for motor power too and not just sound cutout... I have another inquiry to BLI, they must be getting sick of me.
As to the actual “keep alive”, I was intending to use a Soundtraxx CurrentKeeper I have, but it’s turning out to be a bit too thick for this particular install. Unless I can find a smaller commercial unit (thoughts?) I might need to rig a capacitor bank to fit available space... but not until I’ve confirmed the connection isn’t for sound only.
Otto K.

[peteski]

Out of curiosity, are the 6 caps on the other side all connector in parallel? If they are, I wonder of that single cap where they advised to attach keep alive also in parallel with those 6 caps?  That would probably be too easy . . . 

[Cajonpassfan]

Pete, I don’t know, can’t tell. And I got a response from BLI but no answer whether the keep alive circuit was sound only or motor control as well. Now my challenge is to make it all fit inside the brass tender. So far, I haven’t been able to figure it out, there is some heavy sheet and angle stock bracing inside the shell 
Otto

[peteski]

Before you commit to doing this, why not build a test setup where you temporarily hook everything up(even leave the model's shells off), then do a test run and see how the model behaves.  That way you will know whether the keep-alive circuit will work the way you want.

[Cajonpassfan]

Yes, good idea, I was planning on doing just that, but now I’m stumped about how to fit it all into the brass tender. It seemed like I had plenty of vertical space to stack the CurrentKeeper on top of the P3, but i don’t. Close but no cigar...
I might have to rethink my conversion candidate.
Otto (scratching head)

PS: just got a good news reply from BLI: it should work for both sound, and lights/motor!

[peteski]

Well Otto, couple of sugestions:

1. Find a smaller (more compact) KA circuit.

2. If you are adventurous, peel off the pink heat-shrink, carefully unsolder the caps, stack them in a way they will fit in the tender, then connect the bank of caps back to the KA circuit board.  These caps are most likely connected in-series (yes, you read it correctly- in series).  The SuperCaps are usually rated for around 2.5V each. Connecting them in series gives the bank of caps a rated voltage which is a sum of all the individual cap's voltages (while the total capacitance is a fraction of the single cap's capacitance).

If the KA circuit board is laid out favorably, you can also even trim it by quite a bit.  Are you up for this? 

[Steveruger45]

OTTO
What about one of these?
https://tcsdcc.com/Zen/index.php?main_page=index&cPath=69

[Cajonpassfan]

Lol Pete, I’ll take Curtain #1....
Not that I’m not adventuresome (I am in N Scale, aren’t I?) but I have plenty of other projects where the CurrentKeeper should work as is.
Steve’s link is a possibility (thanks Steve!) TCS KA-1 is .244” (6.2 mm) thick, vs. the one I have, at .277 (7.1 mm). A point nine mm difference😬 it would be good to find something even smaller/thinner.
Even so, I need to figure out whether this tender is even doable. I took a Dremel with a cut off disk to the bottom eL brackets, got it hot to the point of melting some solder joints and barely made a dent in it. It seems Goldrich Models used some kryptonite to build this thing😜 It is very well made but not built for ease of disassembly for sure.
Meanwhile, I think I’ll order the KA-1, I can always find good use for it elsewhere if the tender modifications don’t work out.
Thanks for your feedback guys!
Otto

[Steveruger45]

Otto, this one is 6mm thick.
https://store.sbs4dcc.com/Soundtraxx810140TsunamiCurrentKeeper.aspx
But it looks the same as the one you have !.

[Cajonpassfan]

Thanks Steve! Hmmm, longer, wider, .2 mm thinner. Will have to ponder.
Appreciate your help,
Otto

Edit: it is the same one I have, and the specs on the website are wrong. Mine is .277 thick, 7.1 mm. Go figure. Maybe they measured it before wrapping it...
O.

[jdcolombo]

I've used the TCS KA-1 successfully in small tenders with a LokSound.  The Paragon Decoder is physically much bigger than the TCS, but the TCS is only 6mm thick, and I think might successfully stack on top of the Paragon.  Although the TCS is also 27mm long, so you have to have enough length for it.

John C.