Hi All,
I'm thrilled to report that after getting my mainline loop running (minus turnouts to yard, siding and branch) and running my DC locos on it for a few weeks, I finally ventured to hook up my NCE Power Cab starter kit and was able to watch my DCC locomotive light up, sound off, and come to life. It worked beautifully, and I'm very happy because I bought the engine (SP&S custom painted Atlas YB RS-3 fitted with DCC) almost a year ago and only saw it operate once in a hobby shop I took it to.
I bought the NCE Power Cab Starter kit at the same time, new. The wheel on my throttle doesn't quite make a smooth increase or decrease in speed -- same issue as the member was having here -- which is a bummer and I'll have to act fast if I want it fixed under warranty, but I'm not really that bothered about it. I'm just thrilled to run that engine and have it make so much wonderful noise.
Why I'm posting -- I originally interrupted the wires to the track with a little switch, so that I could leave my DCC cab hooked up while also continuing to run my DC stuff, but the DCC loco wouldn't budge or make any noise with the switch there. I removed the switch and just twisted the track wires directly to the wires from the DCC unit. That worked.
So my question is, why didn't it work with the switch in? Was it because it was a SINGLE pole double throw? Should it have been a DOUBLE pole double throw?
Thanks,
-mdf
Returning to model railroading after 40 years and taking unconscionable liberties with the SP&S, Northern Pacific and Great Northern roads in the '40s and '50s.
DPDT center off.
I run dual mode, DC or DCC and made my connections to the track automatic. I use a DPDT relay with the coil powered by the accessory terminals on the DC power pack.When I turn on the DC power pack the relay pulls in and switches the rails from the DCC controller to the DC power pack. Fool proof, the DC and DCC can’t be connected to the rails at the same time.Mel Modeling the early to mid 1950s SP in HO scale since 1951
Bakersfield, California Aging is not for wimps.
rrebellDPDT center off.
@rrebell, thanks. That did it. Works wonderfully. @mel, I think you've told me this before when I was asking how to set this all up before I was really able to absorb all the helpful information. I like your method a lot. I'm not good with electrical diagrams but I think I understand most of your illustration. The numbers connections at top correspond to the numbered holes in the relay. The only part that I don't get is the item midway along the bottom wires ..numbers 2 and 7. Is that the coil you mentioned? What are the exact products you used, both for the 8-hole relay and the AC/DC coily thing?
BTW, right now there are just two track wires. I have purchased 14-gauge stranded wire for a pair of bus wires under the mainline, and 22-gauge wire for feeders, but have not installed them yet. The loop is small enough that the tiny feeders that came with the power pack do a fine job and locos don't lose power even at the far end of the layout. But I do intend to install a bus-wire system and feeders.
Yes, That is the symbol for the relay coil.
https://www.ebay.com/p/667597080?iid=162443704407
Mel Modeling the early to mid 1950s SP in HO scale since 1951My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California Aging is not for wimps.
Be VERY careful. You really don't want to wire these dual-system things wrong. Not only won't they work, but they might never work again. You must not ever have the systems connected electrically, ever.
My suggestion is to have one and only one outlet for both DC and DCC. That will force you to unplug one system before plugging in the other. The DPDT switch should work properly, but the belt-and-suspenders approach gives you an extra level of protection.
It takes an iron man to play with a toy iron horse.
Mr. B is correct! I’ve been using the relay method for many years (14 yrs) and so far I haven’t dinged anything but a newbie might not be so lucky. Being conscious about not having a non DCC locomotive on the track when using DCC could be bad.Using a plug to switch power packs is much safer but you must still to be conscious of what is on the track! Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps. Bakersfield, California I'm beginning to realize that aging is not for wimps.
MisterBeasleyYou must not ever have the systems connected electrically, ever. My suggestion is to have one and only one outlet for both DC and DCC.
i only have one outlet. Here it is:
The DCC Power Cab power is lower left, the DC power pack is lower right. Outlet is at top. Only one of the plugs can go in it, so I've satisfied your second injunction. But as for the first, I'm not sure. The systems are connected electrically through the DPDT switch, aren't they? What happens if I have the DC power pack plugged in and a DC engine on the track, but I accidentally throw the switch to the DCC side, or vice versa? Maybe I have my DCC loco on the track and the DCC cab plugged in but accidentally throw the switch to DC? I thought the DPTD was supposed to protect my systems by making those connections impossible at the same time.
Incidentally, until I have a much more sophisticated system and much more track laid, I only ever have one engine out of its box at a time. After a run, I take it off the track.
LastspikemikeAlso, only dual mode decoders will run on DC powered track. Even dual mode decoders can be programmed to ignore a DC powered track for technical reasons related to possible runaway conditions. If a dual mode decoder equipped locomotive won't run on a DC powered track check that DC mode (analogue) has not been disabled. You need to use the "look up" chart in your DCC decoder manual to find the CV number and the value you need to enter to switch the DC or analog mode on or off as desired.
Mike, I don't know what kind of decoder is in my engine. I got it used on eBay. It was an old Yellow Box Atlas (Japan I think, or China, not Roco) that had been fitted with DCC. I didn't really want to try it on DC at first because I had a power pack that seemed pretty "pulsy" and I'd heard that that can blow the brains out of a DCC engine. I finally got a MRC Power Pack that would supposedly be safe, but I've seen long threads about this that make my head spin.
Now that I reflect, i think I recall that I gave it a quick test and the engine wouldn't respond to DC even from the newer MRC power pack.
-Matt
RR_MelYes, That is the symbol for the relay coil. https://www.ebay.com/p/667597080?iid=162443704407
@Mel, I get the relay piece. What I'm wondering about is the other thing in the 2 and 7 lines.
In the screenshot of your reply below, I think the relay you've linked to is what I've circled red. But what is the thing that I've circled blue?
That is a full wave bridge rectifier to change the DC Power Pack accessory terminals AC voltage to DC, DB107.You could use an AC relay but they sometimes have 60hz buzz, DC relays are silent.Mel Modeling the early to mid 1950s SP in HO scale since 1951My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California Aging is not for wimps.
Mel, thanks in advance for your continued patience. (I did warn all of you that I am a complete ignoramus when it comes to things electrical.)
So if I'm reading you correctly, I would hook up my MRC Power Pack so that its DC wires went to connectors 3 and 6 on the relay, and its AC connections went to 2 and 7 on the relay, but with each of those lines (2 and 7) being interrupted by two prongs of the bridge rectifier. And then my DCC cab would have lines going to relay connectors 4 and 5, and the track wires would come in at connectors 1 and 8.
Am I getting that right?
And that setup enables you to simply plug in your DC pack to switch it over from DCC automatically?
You got it!
The AC is changed to DC through the DB107, the DC out of the DB107 goes to the relay coil. The coil doesn't care which terminal is + or -.The DB107 has the terminals marked for + & - DC out to relay. The DB107 ~ terminals are AC in from the Accessory terminals.When you turn on the DC Power Pack the relay will pull in, powered by the Accessory terminals, and switch the rails from the DCC Controller to the DC Power Pack. Mel Modeling the early to mid 1950s SP in HO scale since 1951My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California Aging is not for wimps.
crossthedogMel, thanks in advance for your continued patience.
Mel gives some of the best advice available.
I cannot begin to tell you of all the neat products and techniques he has brought to my attention.
Thanks Mel!
-Kevin
Living the dream.
Hey Mel (or anyone who knows), I have several follow-up questions:
1) That relay you linked to. I asked the seller how you connect wires to the pins and whether there was a female socket I should be looking into. He said yes, and that it's pretty a standard 8-pin socket. If you know, could you tell me if the item at the following link is that socket?
6 Pcs Metal 8 Pin DIN Female Socket Hulled Panel Mount Connectors Soldering U9
2) After you set this system up, how do you KNOW whether or not it's working when you plug in your DC power pack? I mean other than putting a DC engine on the track and maybe finding out it isn't. You said you've used this system for many years without issue, which implies you're pretty confident of the system. What feedback indicates a successful switch from DCC to DC?
3) How do you connect wires to those tiny flat prongs on the DB107 bridge rectifier?
Sorry if this is bonehead basic stuff. Thanks for the help, as always.
No, the sockets are referred to as Octal. Octal KRPA Relay Sockets.
https://www.google.com/search?q=octal+krpa+relay+socket&ei=DSzeYIzHCNbO0PEP2omloAs&oq=octal+krpa+relay+socket&gs_lcp=Cgdnd3Mtd2l6EAwyBQgAEM0COgcIABBHELADOgYIABANEB5KBAhBGABQwPkBWO6RAmDitAJoAXACeACAAcgBiAGVB5IBBTAuNi4xmAEAoAEBqgEHZ3dzLXdpesgBCMABAQ&sclient=gws-wiz&ved=0ahUKEwjMga6d4cLxAhVWJzQIHdpECbQQ4dUDCA0The obvious, you hear the relay snap when you turn on your DC power pack. You can check the track voltage with a meter or a bulb. The voltage will vary with throttle on the DC power pack. You could use a bulb or LED across the relay coil for a visual indicator, on would be DC power pack connected to the rails.
They make an 8 pin DIP socket for the chip. I just soldered hookup wire to the pins on the DB107.Mel Modeling the early to mid 1950s SP in HO scale since 1951My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California Aging is not for wimps.
RR_MelNo, the sockets are referred to as Octal. Octal KRPA Relay Sockets.
Thanks, Mel. Now that I look back at your first illustration I see that socket. Didn't realize what that was at first.
I’m sorry for the bumpy reply, as Randy said I leave out a lot of pertinent information. I always have to go back and edit my posts.Mel Modeling the early to mid 1950s SP in HO scale since 1951My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California Aging is not for wimps.
LastspikemikeHaving to consciously plug in the correct powerpack will serve as the reminder to remove all DC locomotives from powered track.
Mike, yes, I think that's the best route for me as well. Visual, physical reminders in the space-time continuum where I actually live. I also don't have a roundhouse or any service sheds yet, or any block wiring, so the locos come off after they finish a run.
RR_MelI’m sorry for the bumpy reply
Mel, not at all. I have to ask a lot of detail questions after I get some context. I don't retain information until I have that "outer ring" of context to hook the data to.
I do wonder about one more thing, and that is, what happens when you switch back to your DCC cab? Does the relay switch back automatically? At first I thought no, because it's only connected to the DC pack (I think even this is not true, looking at your diagram again). But then I thought, the location of the AC connections on the DC power pack is really incidental, they could be anywhere, right? But then I thought, well, Mel is only trying to protect the system from DC locos on DCC-powered track, not from DCC locos on DC-powered track (although I've heard that you can blow the brains out of older DCC encoders that way).So I really don't know how the final operation of this relay set up works.
What do you do when you want to run DCC again? Do you throw a switch manually?
Thanks, all.
OK, here we go.The relay is controlled by the DC power Pack. With the DC power pack off the relay is in the DCC position. When you turn on the DC power pack the relay pulls in and disconnects the track power from the DCC controller and connects the DC power pack to the track.I operate my layout more on DC than DCC, I only run in DCC mode when I want sound or remote control of onboard lighting, such as turning the lights on and off in my passenger cars.I wired the lighting in my passenger cars with a DCC mode bypass using a magnetic latching reed switch so that I can turn on and off the lights with a magnet.I wired all (70+) locomotives for DCC operation using the standard NMRA 8 pin plug. I only have 13 DCC decoders so I use a standard DCC to DC shorting adapter when the locomotive will be operating in DC mode.I need to say that my layout was designed and built 35 years ago before DCC and I didn’t think I would be running multiple trains. By design I can only run one train at a time on my mainline. It is a John Allen original G&D type twice around mainline.I model the mid 1950s era and don’t have any newer equipment than 1956, mostly steam, PAs and E7s for passenger service. Every once in awhile a SP GS-4 pulling a Daylight passenger consist and a Cab Forward pulling a Lark.I would say that most of my locomotives are in DC mode so I don’t have a problem with DCC. I wired my layout for DC block control so I can turn off the track power in my yard and sidings to park DCC locomotives while operating in DC mode and vice versa. Mel Modeling the early to mid 1950s SP in HO scale since 1951My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California Aging is not for wimps.
RR_MelOK, here we go.
Ha, I smiled so wide the back of my head fell off when I saw this. You have truly answered all the questions I could have thought to ask. And wow, I love that layout design... I could almost have fit it into my space because it's the same basic shape as mine, but I like that you get the twice around benefit and you can reverse direction one time without backing up and multiple times if you use your "cross valley" track as a wye. Plus you have beaucoup tunnels, a spacious railyard and space for roundhouse and services. My turntable will be small and cramped and the yard is only three tracks, and how I will configure my terrain for tunnels remains problematic. Thanks for sharing all that (not for the last time, I bet).Here's mine. Switches have moved a bit in the as-built but this is basically what's taking shape.
I’m not into operations and your layout looks very busy. I prefer building and gadgetry over a switching type layout. With the help of my uncle I got started in electronics at the early age of 8, I had my first amateur radio transmitter that I built on the air at 10. I was in the two-way radio industry for 50 years.I do lean toward the electronics side more because of my background. My mother was into crafts so that helped me on the scenery side. Mel Modeling the early to mid 1950s SP in HO scale since 1951My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California Aging is not for wimps.