Keep Alive for Paragon 3 sound decoder?

[Cajonpassfan]

For those of you still awake following this thread, I took a Dremel and gingerly carved out the offending bracing along the bottom of the brass tender. I also carefully ground down various interior protrusions that kept the outside detail soldered on. I had to wrap the shell in a cold wet kitchen towel to dissipate the heat, but the end result is a cavity almost big enough to accommodate both the Paragon 3 and the CurrentKeeper😬
John, I have an ops session at a friend’s layout Saturday, and afterwards a planned visit to Arnie’s Trains. I think/hope they carry the KA-1 and if so, I’ll get it; it should fit.
I think the 13x18 mm speaker will fit into the fuel compartment that’s fully encased in brass. I just need to fill the gaps up top. I’ve yet to decide whether it fires up, into the top of the oil bunker, or down, into the enclosed fuel compartment. The compartment/sound chamber is about 3,400 cu.mm, should be plenty big enough?
That’s it for now, good night.
Otto K.

[peteski]

Making good progress Otto!
And yes, the bottom brackets on brass tender shells are made from heavy gauge brass.

[Steveruger45]

Glad to see it is working out Otto.
I would fire the speaker up.  A sealed enclosure of the volume you mentioned will be plenty plenty plenty big enough.
My only concern would be if you use the thin brass of the tender as the enclosure you may get some undesirable resonance.
I would tend to make an enclosure to insert into the tender or line the brass enclosure with styrene.  You would still have plenty of volume.

[Cajonpassfan]

Thanks guys. I’actually prefer to shoot the sound forward, into the loco cab, but there isn’t a good way to make it work here without using a smaller speaker. Pointing the speaker up will shoot the sound into another tight box, the fuel bunker, so I think I’ll need to find a way to get the sound out. (I can’t exactly drill a bunch of little holes in it like I could on a coal burner). Maybe a tiny gap along the base of the bunker, I’ll figure something out when I get there.
Steve, as to the issue of potential resonance, that hasn’t occurred to me, but I’m not too concerned. I’ve done installs in brass tenders before, granted, using the entire tender body as an enclosure, and they are the best sounding engines I own. These tenders are very tight and solid, not much chance for vibration I don’t think. Time will tell...
Otto

[Steveruger45]

I’m not sure of possible resonance issues either as I’ve never done a brass loco.  Just something that popped into my head to consider due to the metallic nature of the enclosure rather than that of a more “sound dead” material.  But I’m glad to learn from your experience on this.   The proof really is in the eating as they say afterall.
Just an idea wrt directing the sound forward, what about staying with the bigger speaker, leave the top portion covering it intact and porting the somewhere on the front end of the tender?
Following this with great interest Otto. It’s looking good.

[MK]

These tiny speakers probably don't have enough power to resonate heavier brass (as opposed to thin plastic).

[nickelplate759]

If you do get noticeable resonance you can try some tricks to dampen it, but they do take up space.  For example, you could take some thin sheet lead and glue it to the brass panels (most likely the larger flat ones) where you can find space.  It doesn't have to cover the whole sheet - just having it in a few places will change the resonance, and that could be enough.  You could even experiment by applying it with double-sided tape.

[jdcolombo]

Whether mounting the speaker in the brass surround will be OK depends on the thickness of the brass and how well it can be sealed.  I tried mounting the speaker in the brass surround on my Key Berkshire, but ended up building an enclosure because (1) the brass leaked and (2) it "buzzed" when I blew the whistle.  YMMV.

John C.

[Cajonpassfan]

...
Just an idea wrt directing the sound forward, what about staying with the bigger speaker, leave the top portion covering it intact and porting the somewhere on the front end of the tender?
Following this with great interest Otto. It’s looking good.

Well, that’s exactly what I do normally, but port it down below, below the footplate where a black opening is virtually invisible. Here, a forward port would need to be up high, not so easily disguised. I’ll deal with it when I get there; still have a lot of other issues to work out first, like getting it to run properly with this decoder.
And George, I really don’t think resonance will be an issue.
Thanks for your interest though,
Otto

[Cajonpassfan]

Well dang, I’m having a hard time trying to remove the flush cut wires and insulation inside the male side of the connectors...see pics. Tried Exacto blades, needles, miniature Densply files, and while some of the stuff is coming out, I’m concerned I’m damaging the contacts in the process.
The cleanest fix would be to buy a new connector and just use the male side of it. Does anyone here know specifically what IDC connector this is and where I might buy some?
Thanks,
 Otto K.

[peteski]

These look like IDCs (Insulation Displacement Connectors).  They are solder free and the wire is simply pushed into them using a special tool.  The plastic shell also has strain-relief barbs which prevent the wire from easily being pulled out.  But if you are careful, you can pull the wires out.

I worked on a QSI decoder which uses similar connectors. I ended up fabricating a tool which allowed me to push new wires into each location.  But I think that if I was in your situation, I would simply remove the connectors from the decoder and then solder wires directly to the metal pads on the decoder.  But that is also risky since you have no way to heat up all the connector pins a the same time (to melt the solder and remove the connector). I would carefully try to destroy the connector (maybe grind it down using a Dremel tool), then once the solder pads are visible, unsolder each remaining pin stub, one by one.

[Cajonpassfan]

Thanks, Pete. Well, yeah, I know they are IDC’s, see my previous post, just not the spec. I removed the flush cut wires as carefully as I could, but I’m getting continuity on some but not all the replacement wires; I must have damaged some of the minuscule internals on the male side, hence my inquiry about the specific item to order. I found something that looks kind of like this IDC on a Chinese website, but the minimum order is 1,000 pieces😬
I don’t think I have the skills remove the female side and solder directly to the decoder, if that’s what you’re suggesting. Besides, I need to be able to separate the loco from the tender, and the connector is perfect for that.
Otto

[peteski]

Thanks, Pete. Well, yeah, I know they are IDC’s, see my previous post, just not the spec. I removed the flush cut wires as carefully as I could, but I’m getting continuity on some but not all the replacement wires; I must have damaged some of the minuscule internals on the male side, hence my inquiry about the specific item to order. I found something that looks kind of like this IDC on a Chinese website, but the minimum order is 1,000 pieces😬
I don’t think I have the skills remove the female side and solder directly to the decoder, if that’s what you’re suggesting. Besides, I need to be able to separate the loco from the tender, and the connector is perfect for that.
Otto

Yes, you understood my post correctly.
But even if you have a new connector, if you don't have the special tool (or make one), you will have really difficult time pushing the wire into the connector without damaging it.  If the wire's insulation does not get properly punctured when the wire is installed, there will not be a solid connection.

[wvgca]

if you want to make your own stay alive [ instead of using a commercial one] does anyone have ballpark recommendations for the resistor and diode used in there [assuming 2.5v caps in series]

[woodone]

Otto,
That tender looks a lot like the one I am working on right now.(Pecks River Brass) 4-6-4.
The one I have has a removable oil tank that is held in place with one screw. Looks like you have the same thing?
I removed the oil tank and removed the sloped bottom for the coal load. That freed up some room. I may remove the mounting bracket too.  But I will have to figure out how to retain the oil tank.- that should free up more room. I have not got to that point.
Big tip here. I use dental burs to work on brass. They will cut brass very well and don’t shake the model all over the place.
There are a bunch of burs you can use. I use one that is used for crown work. And a reverse cone shaped one .
If you are interested I can give you a link has to what I use. Has they say!! (Best thing since sliced bread)
I chuck them up in my Dremal and adj speed to task at hand.
If you are game, I have had success in installing IDC connections . I use a wooden coffee stirrer filed down to a very fine edge and about the length of the IDC Aline the wire over a IDC slot a use the wooden stick to press the wire into to connector. Then I check the connection- has worked for me many times.