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OvermodDoesn't the keep-alive just go in parallel with the DC power to the decoder?
The DC power to the decoder is after the rectifier (diodes) in the decoder. The input to the decoder is the DCC booster output, which is not DC, but an AC signal of sorts at a high frequency, containing the DCC signal packets. The output of a simple 4 wire decoder is PWM DC to the motor.
Inside the decoder, the DCC signal is rectified and pulse width modulated to effectively vary the DC voltage to the motor. The decoder must also decode the DCC signal packets and act on those packets meant for that decoder. Additional outputs for lights and speakers are present on more complex decoders.
The energy of the "keep alive" was originally only wanted to keep the decoder "on" and the motor turning during a momentary loss of track power because keep alive energy was/is very expensive in terms of real estate, effort to add, and cost. Therefore, the keep alive was inserted directly after the rectifier (+/- pads on many decoders).
Newer decoders built with keep alive in mind may want to have other functions powered during track power dropouts, and therefore may change the decoder circuits to power those functions from the keep alive as well.
Fred W
Doesn't the keep-alive just go in parallel with the DC power to the decoder?
drgwcs The way QSI built those decoders as so non standard compared to others I'm not sure even the guy that designed it would know. I have never really heard of anyone doing it.
The way QSI built those decoders as so non standard compared to others I'm not sure even the guy that designed it would know. I have never really heard of anyone doing it.
I wish I understood electronics well enough to know why this should be so difficult. Aren't the Keep Alives designed to attach to specific components of a decoder. Don't the QSI decoders have those components.
As far as I can determine, the blue wire of the KA goes with the blue wire of the decoder. The question is where to attach the black wire. Why is that a mystery?
John-NYBW wjstix Unfortunately, the BLI switchers have a decoder that's like a lightboard, so you can't just unplug a decoder and plug in a new one (with Keep Alive connection). I guess the options you have would be to take it to a hobby shop or send it to someone like Tony's Train Exchange to install the Keep Alives, or remove the decoder and hardwire in a harness that will accept a TCS decoder that you can attach the Keep Alives to. https://tonystrains.com/services I had no intention of swapping out the decoders. I would like to know how to attach the Keep Alives (a KA3 and a KA4) to the existing QSI decodoers. Apparently, no one in the civilized world knows how to do that.
wjstix Unfortunately, the BLI switchers have a decoder that's like a lightboard, so you can't just unplug a decoder and plug in a new one (with Keep Alive connection). I guess the options you have would be to take it to a hobby shop or send it to someone like Tony's Train Exchange to install the Keep Alives, or remove the decoder and hardwire in a harness that will accept a TCS decoder that you can attach the Keep Alives to. https://tonystrains.com/services
Unfortunately, the BLI switchers have a decoder that's like a lightboard, so you can't just unplug a decoder and plug in a new one (with Keep Alive connection). I guess the options you have would be to take it to a hobby shop or send it to someone like Tony's Train Exchange to install the Keep Alives, or remove the decoder and hardwire in a harness that will accept a TCS decoder that you can attach the Keep Alives to.
https://tonystrains.com/services
I had no intention of swapping out the decoders. I would like to know how to attach the Keep Alives (a KA3 and a KA4) to the existing QSI decodoers. Apparently, no one in the civilized world knows how to do that.
Hello All,
wjstix...the BLI switchers have a decoder that's like a lightboard, so you can't just unplug a decoder and plug in a new one (with Keep Alive connection).
The OP listed the locomotives as...
wolfman hal1. Bachmann Baldwin Modern 2. Bachmann 50 Ton 2 Truck Climax
They did not specify the manufacturer of the decoders; Original Equipment Manufacturer (OEM) or After Market. They only specified the wiring harness...
wolfman halThe decoder is on an 8 pin connector.
I suspect the OEM PCBs are "DCC Ready" which adds a layer of complexity when trying to install ESDs.
For my Bachmann motive power, I have standardized the decoders to Digitrax DH126 and DH166 series. Some hardwired, some using an 8-pin NMRA-compliant plug.
This allows me to use the Digitrax PX108-2s as the plug for the ESD is built into the decoder.
Hope this helps.
"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"
John-NYBW I need Keep Alive Installation Instructions for Dummies. I've been searching for over seven years for such instructions. Still looking. Meanwhile my Keep Alives remain on the shelf and my SW7s keep stalling out.
The problem is that the original "Keep Alive" gizmos were made by TCS decoders, to be used with just their decoders. Most TCS decoders made since Keep Alive was introduced has a small receptacle to plug in the KA device. For a time, that was the only such device, so figuring how to connect it to another company's decoder was kinda hit-and-miss / trial-and-error. Kinda like trying to fit a Chrysler part into your Chevy's motor. Now, several companies have their own versions, but they are primarily designed to be used with their own decoders.
John-NYBWThese are QSI decoders...
Good to know which decoders you are working with John-NYBW.
My question was to the OP in hopes of answering their inquiry.
Until we know what decoder(s) and ESDs they are dealing with it is difficult to help them.
jjdamnit Knowing which decoder(s) and ESDs you are working with can help answer your inquiry. I suggest contacting the decoder(s) manufacturers' for compatibility and installation. Hope this helps.
Knowing which decoder(s) and ESDs you are working with can help answer your inquiry.
I suggest contacting the decoder(s) manufacturers' for compatibility and installation.
These are QSI decoders which are probably considered to be from the DCC Stone Age. I've been looking for specific installation instructions for seven years with no luck.
wolfman hal what decoder(s) are you using?
Please consider narrowing your inquiry to, "I am using 'X' brand decoder(s) with 'Y' brand Energy Storage Devices (ESDs)."
Even though the National Model Railroad Association (NMRA) strives for interoperability among DCC components, how each manufacturer arrives at that "standard" can be vastly different.
Not all (ESDs) are the same and some are simply not compatible with other manufacturers' decoders.
Most ESDs have two (2) wires, while ESU "Power Packs" have three (3).
I've been trying to find instructions for installing Keep Alives in my first generation BLI SW7 switchers that are in plain English. They all use terms I am completely unfamiliar with. They lose me when they start out, "Find the....". I have no idea what the component is that I am supposed to find or what it looks like. I admit to being somewhat illiterate when it comes to electronics. I need Keep Alive Installation Instructions for Dummies. I've been searching for over seven years for such instructions. Still looking. Meanwhile my Keep Alives remain on the shelf and my SW7s keep stalling out.
Here is a thread I started back in 2015. None of it helped.
Installing a Keep Alive capacitor in a BLI SW7 - Model Railroader Magazine - Model Railroading, Model Trains, Reviews, Track Plans, and Forums
I prefer not to spend the extra money right now if possoble. The decoder is on an 8 pin connector. Can't you just solder to the solder side of the pin?
tstage Looks like a bad (or "members ONLY") link, Mark? Tom
Looks like a bad (or "members ONLY") link, Mark?
Tom
Not sure why the site is down. It can still be accessed through the wayback machine ....
http://web.archive.org/web/20220317052613/http://www.members.optusnet.com.au/mainnorth/alive.htm
Mark.
¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ
I second the use of a decoder with the Energy Storage Device (ESD) built-in to the decoder like the TCS KAM series.
The TCS KAM4 LED also has built-in resistors for LEDs in the same small package.
I find it ironic that locomotives that would benefit most from ESDs have the least amount of space to install them.
most decoder boards will not have readily labelled pads ... instead you should use the blue as a hot, and a spot next to the main diodes as a grounding spot ... a multimeter will help definitely ...
it's not that hard to do, just can be kinda putzy, lol . i doubt that you will find an easily followed picture of what you want ..
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
This site gives lots of answers on where to install stay alive capacitors ....
http://www.members.optusnet.com.au/mainnorth/alive.htm
wolfman halAlso, has anyone used the new smaller KA2 and if so, did you like it?
I did install some earlier TCS KA2s on some locos and they performed just fine. You might want to consider replacing the existing decoder with one of the TCS decoders with the keep alive integral with it such as the KAM-4
https://www.tcsdcc.com/product-page/kam4-led
This one has lighting outputs already reduced for direct wiring to LEDs without additional resistors, too. "Street price" is about $60.
https://www.litchfieldstation.com/product/tcs-kam4-with-led/
I think the Bachmann "DCC On Board" decoders are made by Soundtraxx, at least they were in my Bachmann B&O EM-1 and a photo of the Climax shows a similar board. Finding the blue+ pad should be relatively easy but finding the proper ground location might be a challenge.
Good Luck, Ed
What decoders are you going to use?
"The true sign of intelligence is not knowledge but imagination."-Albert Einstein
http://gearedsteam.blogspot.com/
I have two small engines that they have decided do not like to cross a turnout without stalling. I know why so this is not the discussion. I want to install a KeepAlive/Stay Alive in each.They will be connected to the original decoders. I can not find instructions specific to these small engines. Wire connections etc. I plan on using a TCS KA 2. I looks to be small enough to fit.
Most YouTubes are old and don't really answer the question. Any one know a good Video or a good source?
Also, has anyone used the new smaller KA2 and if so, did you like it?
1. Bachmann Baldwin Modern
2. Bachmann 50 Ton 2 Truck Climax