Again this may sound dumb, but why are there HO scale decoders and N scale decoders? From what I have seen they have the same functions and handle the same power range. My Blue Line AC 6000 requires a N scale decoder due to lack of room.
So if a N scale decoders is safe to run in a HO scale engine, why not run all N scale decoders in HO engines?
Second part of this question, can and what would you use as a heat sink. As most of you know I had two HO scales decoders melt. They where both in narrow body engines. I now run way shorter trains so I should be past that stage, I hope! One of the reasons I was thinking about using N scale decoders there would be more breathing room and maybe room for a heat sink.
Cuda Ken
I hate Rust
Well there could be multiple reasons why you have two functional spec matching decoders, one marked HO and another N scale. But I'll take a few guesses.
The HO might be cheaper to make due to large components. (Easier to make)
The HO might have more appropriate connections (9 pin JST or 8 pin NMRA socket)
The HO might be designed to run with a higher average current.
The HO might have additional area to disapate heat.
The HO decoder's Back emf might be calibrated for HO size motors.
Someone else on here asked about heat sinking decoders. My reply was "Use a thin layer of Bathroom Caulk. Attach it to metal if possible."
Don - Specializing in layout DC->DCC conversions
Modeling C&O transition era and steel industries There's Nothing Like Big Steam!
Simple answer:
O and G scale decoders were developed first, and as electronics technology shrunk the components they could make smaller and smaller decoders to where they eventually could be fit into HO, then N scale. Now you can get them even for Z scale.
The first HO decoders I ever purchased were almost as big as an Oreo cookie. Today there are some that are smaller than a dime.
The scale rating is the smallest size loco it's supposed to fit. As long as your engine's stall current doesn't exceed the decoder's rating, it will work in a larger scale.
Martin Myers
DigitalGriffinSomeone else on here asked about heat sinking decoders. My reply was "Use a thin layer of Bathroom Caulk. Attach it to metal if possible."
I don't see how this will work. Most decoders I've seen are either wrapped in some sort of heat shrink material or have some exposed electrical traces etc on the bottom of the circuit board. In order for a heat sink to work, there has to be some contact between the electrical component and the heat sink itself. Obviously you can't have that if there are exposed electrical thingys on the board bottom. And those decoders that are shrink wrapped will not allow heat to easily escape from the decoder because the shrink wrap is not a good thermal conductor. And I'm pretty sure that bathroom caulk is also a poor thermal conductor. From what I remember, there was a special thermal grease that was used between electrical components (power transistors for example) and the associated heatsinks. But if there is no way for the heat to get out of the decoder or metal contact is not allowed, my opinion would be that the only thing the caulk accomplishes is to keep the decoder from flopping around in the shell.
maxman But if there is no way for the heat to get out of the decoder or metal contact is not allowed, my opinion would be that the only thing the caulk accomplishes is to keep the decoder from flopping around in the shell.
But if there is no way for the heat to get out of the decoder or metal contact is not allowed, my opinion would be that the only thing the caulk accomplishes is to keep the decoder from flopping around in the shell.
I'm with maxman on this one -- bathroom caulk is not going to transfer heat from the decoder. Decoder manufacturers all say to allow for sufficient air flow around a decoder for cooling, and the caulk will prevent that from happening. If the decoder needs to be fastened to prevent it from flopping around, I use double-sided white foam tape.
Under normal operating conditions, which I know from previous posts that Cuda Ken doesn't do, a decoder needs no additional heat sink.
I have some Digitrax G-scale decoders that are mounted on large aluminum heat sinks because of their heavier current rating, but HO or smaller decoders can't have heat sinks added because doing so would defeat the ability to make them small. That's why you're supposed to know the stall current of your engine and not overload the decoder.
I haven't done any studies but I don't think bathroom caulk has very good heat transfer properties. As for heat sinking decoders - all the major brands have a power rating which is the maximum current they can handle as they come - ie, if they are wrapped in palstic, they can handle the rated current without removing the palstic or adding heat sinks. Larger decoders for O and G often have instructions for adding a heat sink, they don't often come with them because they aren't always needed, add to teh cost,a nd also make the decoder that much bigger.
As for why not use N scale decoders all the time in HO, N scale decoders cost more, usually. Making things smaller usually increases the price - heck most Z scale decoders can handle the current of modern HO locos, why not use Z scale decoders? I think it's some poor planning when a loco as HUGE as an AC6000 doesn't have enough space around the decoder plug for a typical HO size decoder. What the heck did they do in there, put 4 speakers?
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
maxmanI don't see how this will work.
Use of silicone caulk is quite common for electrical components.
It has a decent thermal conductivity and conduction of heat is always preferable to convection (air) as air has a high insulating factor in a dead space.
The trick is to use a thin a layer as possible. I do this with my decoders and it works fairly well.
-D
Electronics Electronic components are sometimes encased in silicone to increase stability against mechanical and electrical shock, radiation and vibration. This is often called "potting". Silicones are used where durability and high performance are demanded of components under hard conditions, such as in space (satellite technology). They are selected over polyurethane or epoxy encapsulation when a wide operating temperature range is required (−65 to 315 °C). Silicones also have the advantage of little exothermic heat rise during cure, low toxicity, good electrical properties and high purity. The use of silicones in electronics is not without problems, however. Silicones are relatively expensive and can be attacked by solvents.[2] Silicone easily migrates as either a liquid or vapor onto other components. Silicone contamination of electrical switch contacts can lead to failures by causing an increase in contact resistance, often late in the life of the contact, well after any testing is completed.[3] Use of silicone-based spray products in electronic devices during maintenance or repairs can cause later failures.
Electronic components are sometimes encased in silicone to increase stability against mechanical and electrical shock, radiation and vibration. This is often called "potting".
Silicones are used where durability and high performance are demanded of components under hard conditions, such as in space (satellite technology). They are selected over polyurethane or epoxy encapsulation when a wide operating temperature range is required (−65 to 315 °C). Silicones also have the advantage of little exothermic heat rise during cure, low toxicity, good electrical properties and high purity.
The use of silicones in electronics is not without problems, however. Silicones are relatively expensive and can be attacked by solvents.[2] Silicone easily migrates as either a liquid or vapor onto other components.
Silicone contamination of electrical switch contacts can lead to failures by causing an increase in contact resistance, often late in the life of the contact, well after any testing is completed.[3] Use of silicone-based spray products in electronic devices during maintenance or repairs can cause later failures.
That last bit about the silicone migratign and contaminating other components is probably the absolute best reason to NOT use silicone caulk inside a powered locomotive. What is the motor commutatot and brushes other than a couple of electrical switches? Vapor plating on the motor commutator would probably not help it run better...
Plus what they use to pot electronic components is not silicone caulk, caulk has a lot of other additives besides just being pure silicone. Silicone potting compounds have different additives designed to enhance the properties of the cured compound with respect to the issues mentioned - shock, insulation, thermal transfer, etc.
Randy,
Silicone migration only occurs in EXTREME environments like space where there is low pressure, or temperatures high.
Caulk is used all the time to mount decoders. The Bowser VO-1000 with Loksound comes from the factory mounted with caulk.
I use my caulk in a very thin layer on the flat side of the decoder. But I mostly use Tsunami's where they have a heatsink on that side. And for what it's worth, it conducts heat very well.
If you open up the inside of your computer power supply, you're going to find silicone caulk.
Do you need to heat sink most decoders? No. But this will help if you are having heat issues.
If my recommendation bothers you that much, you can go out and buy some double sided thermal tape. It was once used as the interface material between heat sinks and CPU's. But it's much more expensive, and harder to get a hold of.
I would think something like the black RTV silicone would work better than caulk. That stuff is good for over 200 degrees.
I completely agree with the statement about the lack of decoder space in a large loco being poor planing! My Bach Dash 8 doesn't even have room for a 1/4 watt resistor for changing to an LED light! The cab is the only place to put it where it won't rest against the shell. I have to do some serious milling to fit a decoder in it.
I was actually thinking of going with NCE N scale decoders as a standard in my HO locos. Just because they will fit everything I own easily.
As for the size of decoders compared to the size of the locos they're designed to go into, I've across some locos (P2K SW9) where space is really tight. Since the Digitrax DZ125 is my decoder of choice the tight space isn't a problem. As for the decoder having heat issues, I haven't lost a DZ125 yet and I run them in locos ranging from switchers all the way up to my big SDP40F's. They can run all day and not turn a hair.
Dr. Frankendiesel aka Scott Running BearSpace Mouse for president!15 year veteran fire fighterCollector of Apple //e'sRunning Bear EnterprisesHistory Channel Club life member.beatus homo qui invenit sapientiam
Ken, I think the best solution is use a decoder with highest current rating and will fit the space you have. The higher the current rating, the cooler the decoder will operate. You can also remove the shrink tubing, just make sure nothing metalic can touch it, (use foam tape to mount it).
To increase ventilation, "open" the engineer and brakeman's windows, (cut them out).
Jay
C-415 Build: https://imageshack.com/a/tShC/1
Other builds: https://imageshack.com/my/albums
Springfield PA
Modelmaker, so far the highest rating I have found is 1 amp / 1.5 amp like a DH123. Are there higher rated ones? Like I have said, have sower off pulling more than 25 cars with one DCC engine. Decoders are not the only thing I have melted, I have melted the power pick up wires from the trucks to the board as well. Yes, I know I was hard on them.
Couple of the reason I asked about the smaller decoders. I have a Athearn RTR SD40-2 that has a DH123 in it. It is such a tight fit the center hatch does not want to close tight. Decoder is against the board as well. I have a N-Scale decoder in a Blue Line 6000 that I am not running. So I was going to try it in the SD40-2.
Thanks for all the answers.
rrinkerI think it's some poor planning when a loco as HUGE as an AC6000 doesn't have enough space around the decoder plug for a typical HO size decoder. What the heck did they do in there, put 4 speakers?
The engine does have enough space for a HO scale decoder.
This is a Digitrax DH165IP that is installed in my AC6000. I agree with you, it would be nice if I could have used a more common decoder. But how many locos out there suffer the same poor planning and require special decoders.
TONY
"If we never take the time, how can we ever have the time." - Merovingian (Matrix Reloaded)
cudaken Modelmaker, so far the highest rating I have found is 1 amp / 1.5 amp like a DH123. Are there higher rated ones? Like I have said, have sower off pulling more than 25 cars with one DCC engine. Decoders are not the only thing I have melted, I have melted the power pick up wires from the trucks to the board as well. Yes, I know I was hard on them. Couple of the reason I asked about the smaller decoders. I have a Athearn RTR SD40-2 that has a DH123 in it. It is such a tight fit the center hatch does not want to close tight. Decoder is against the board as well. I have a N-Scale decoder in a Blue Line 6000 that I am not running. So I was going to try it in the SD40-2. Thanks for all the answers. Cuda Ken
Digitrax DH123 and DH163/165 decoders are rated for 1.5 amps continuous, 2 amps peak. The N scale decoders are the smallest ones that will have the 8-pin plug - none of the Digitrax N or Z scale decoders have the 9 pin plug. The DN decoders are generally 1.25 amps continuous, 2 amps peak, the DZ series are 1 amp continuous, 2 amp peak. If you are melting these with locos that have motors that draw 1 amp or less under stall (any newer Athearn - even the old Blue Box if they have the gold-sided motor don't draw over 1.5 amps if you apply 12 volts with the motor shaft clamped in a vice) you have way more problems then choice of decoder. Pulling 25 cars is not overloading the loco. Unless you changed them out, Athearn locos don't have traction tires, so they'll slip rather than stall out the motor if you put too many cars on them. And melting power pickups - sounds like you shorted the trucks with that 8 amp MRC booster you are using. It may be time to divide your layout into power districts with some circuit breakers rather than have 8 amps to the track at all places
jasperofzeal rrinkerI think it's some poor planning when a loco as HUGE as an AC6000 doesn't have enough space around the decoder plug for a typical HO size decoder. What the heck did they do in there, put 4 speakers? The engine does have enough space for a HO scale decoder. This is a Digitrax DH165IP that is installed in my AC6000. I agree with you, it would be nice if I could have used a more common decoder. But how many locos out there suffer the same poor planning and require special decoders.
That's good to know - even the TCS site recommends their MC series not an HO decoder for that, which seemed strange to me. I don;t model modern equipment, but I sure know an AC6000 is WAY bigger than a GP-7 and if I can fit standard HO size decoders in a GP-7 there should be much more room in an AC6000 even if it does have speakers tanking up a bunch of the room. There aren't too many I've done that couldn;t fit a standard HO decoder like an NCE D13SRJ. Some certainly are easier if you use a specially made decoder - like the P2K SW7. I'm also not afraid to pull out the factory diode board on a non-sound loco to make more room for the decoder - the diode boards being completely unnecessary once a decoder is installed.
Re N vs HO - also keep in mind that FX feature rich decoders (i.e. DH163 line from Digitrax) enply and extra common and two functions on the end of the decoder that the end user could use. I can't imaging incorporating this on the N scale version as it would be virtually impossible to keep the three pads separate when you tried to solder wires to them.
You'd be surprised. I generally feel my solderign skills are quite good, but I really wouldn;t want to attempt what a friend of mine does when it comes to sodlerign decoders. He scratchbuilds SMALL steam locos in N scale - usually tender drive so there really is hardly any space for a decoder. He uses the smallest Z scale decoders you can find - I think the one from CT Elektronik is currently one of the smalelst if not smallest decoder you can buy. ANd solders the track pickup and motor wires on them. No headlights on them, but just the power wires all in a row - not to mention these are like 1/8" long pieces of wire... Seriously, I have a decent sodlering station with a VERY tiny tip, and a magifier desk lamp and I really don't want to try duplicating his work. Then again, he handlaid all his track to 9mm finescale standards - including puzzle switches, using code 40 rail - and one siding with code 25! yes, 25 thousandth of an inch high - it's more like a bar with rounded edges, there's no real rail profile, but you couldn;t tell without a STRONG magnifier. That was only an experiment - even with turned down scale size flanges it's VERY finicky. The code 40 is rock solid and reliable. And believe it or not it's not too difficult getting an N scale steamer with scale flanges on the track. Me, I'll stick with HO, thanks. LOL.