1.25A is a reasonable value, depending on what you are powering - if you are using this to run LED lights in buildings (use the 5, or even 3.3V outputs for this), assuming resistors are used with the LEDs to set the current to 10ma, that's as many as 100 LEDs while leaving some breathign room. LEDs for structure lighting, you may end up using a higher resistence, meaning each one draws even less current, to keep them from being too bright. That takes some experimentation, but say it works out to 3ma per LED for a nice glow in a hosue without makign the walls see-through, that means you can drive somewhare around 350 LEDs without causing the 1.25 amp polyfuse to trip.
For Tortoises, over 60 of them. On the 12V line.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
rrinkerthere are breakout boards available that you just plug the standard connectors fromt he power supply into - so no need to even open it up. That's an even better way to go than opening it upand cutting wires - if it should ever fail, you just have to obtain another (with the same standard connectors) and plug it in. This is just the first one that came up on a search: https://www.ebay.com/i/172546209045?chn=ps&dispItem=1 This one on Amazon includes the load resistor in case you need it (instructions are to try without first, and solder on the resistor only if needed). It has LED indicators and a pushbutton to turn the power on and off. https://www.amazon.com/SeeedStudio-Breakout-Supply-Computer-Source/dp/B00W0SBUJ0 --Randy
I had no idea there were such gadgets, Note one of the boards is marked Dangerous Prototypes. humor I think.
The second board has 1.25 polyfuses. Are they the appropriate size needed?
Thanks.
Henry
COB Potomac & Northern
Shenandoah Valley
Yes, important point. If you want to use an old computer power supply to run stuff on the layout, you should break the feed up into multiple circuits with individual fuses or resettable circuit breakers. You can get fuse blocks fairly cheap on ebay, with say a single input and 8 fuses with individual outputs. Depending on the rating of the computer supply - if you need that much power on the layout, you might even use 2 or more of the fuse blocks.
Some of the newest stlye computer power supplies are what is known as single rail - the actual supply delivers ONLY 12V, the other lower voltages are generated by DC-DC converters in the unit. That usually menas if you hook nothing to % or 3.3V outputs, you can draw the full rating of the power supply from the 12V side. A 750 watt power supply can deliver over 62 amps on the 12V side. That is why you don't just run that under the layout - 12V at 62 amps makes for a nice arc welder. Suffice to say, just ONE supply is more than enough to light a model city even if there are 1000 LEDs. And then some.
Oh, and there are breakout boards available that you just plug the standard connectors fromt he power supply into - so no need to even open it up. That's an even better way to go than opening it upand cutting wires - if it should ever fail, you just have to obtain another (with the same standard connectors) and plug it in. This is just the first one that came up on a search:
https://www.ebay.com/i/172546209045?chn=ps&dispItem=1
This one on Amazon includes the load resistor in case you need it (instructions are to try without first, and solder on the resistor only if needed). It has LED indicators and a pushbutton to turn the power on and off.
https://www.amazon.com/SeeedStudio-Breakout-Supply-Computer-Source/dp/B00W0SBUJ0
Thanks Don, and Randy.
Mike
My You Tube
mbinsewi OK Don, so the two out of service computer towers I have each have one of these inside? Mike.
OK Don, so the two out of service computer towers I have each have one of these inside?
Mike.
Yes. But these power supplies can put out a TREMENDOUS amount of current. And the cheap ones sometimes skimp on over current protection. If you do it, I recommend these two things to go with it...https://www.amazon.com/dp/B00VLBAF84/?coliid=I12Y7WG7I8HTWG&colid=21O2TG56XVMAJ&psc=0&ref_=lv_ov_lig_dp_it
https://www.amazon.com/dp/B01M63P756/?coliid=IUX92V1TKHSQL&colid=21O2TG56XVMAJ&psc=1&ref_=lv_ov_lig_dp_it
Don - Specializing in layout DC->DCC conversions
Modeling C&O transition era and steel industries There's Nothing Like Big Steam!
Yes. I made one of those, though much simpler - I just pulled out the 5V (for electronics) and the 12V (was going) to power Tortoises and such. Not sure where it got to, or I'd post a picture of it.
I took the top cover off but didn't rip the board out of the chassis. I put a switch on the control line to turn it on and off, and an LED and resistor on the PSGOOD line. I put those in the lid of the case - drilled out for the LED in a simple bezel, the switch, and 3 binding posts (5, 12, and GND).
DO note that in many compute rpower supplies, they don't regulate well without some amount of load, so on mine I mounted a 5 or 10 watt sandbar resistor to the case with thermal adhesive and connected it across 5V and GND. I forget the value, but you can calculate it. Mine worked without it, but the 12V line was rather low, down near 11V, until I added it. Really old ones - 386 and 486 days, often wouldn't even turn on without a minimum load.
Also be careful - if you only recently unplugged the power supply, there are a couple of capacitors in there that are charged up to well over 200 volts and can give you a heck of a jolt.
mbinsewi rrinker Although truth be told, I can do all that with my electronics lab power supply, set it to constant volts, 12V, stall the motor, and read the amps right off it, no meters needed. Electronics labs power supply, do you have info on how you set that up in your web site? Mike.
rrinker Although truth be told, I can do all that with my electronics lab power supply, set it to constant volts, 12V, stall the motor, and read the amps right off it, no meters needed.
Electronics labs power supply, do you have info on how you set that up in your web site?
To measure current put this in series with the outputhttps://www.amazon.com/DROK-Accuracy-0-3-0000A-Ammeter-Amperage/dp/B00QDD38UW/ref=sr_1_10?ie=UTF8&qid=1522861173&sr=8-10&keywords=digital+ammeterThis will result in a slight voltage drop though. (The only downside) The new Bachmann wall warts ARE JUNK. I had two in a row putting out voltage WELL ABOVE spec.
Have been reading the replies. Not usually a "worrywart" but have a basic question.
The youngster next door has been playing with his Bachmann HO train set given to him a few years ago. I know for sure he is using a 6607 power pack. If I get the opportunity to speak to his dad, what should I suggest would be the least expensive alternative?
As always, thanks.
I have something like this, actually, this same model.
https://www.ebay.com/p/Instek-Gpd-3303s-195w-Triple-output-Programmable-Linear-DC-Power-Supply-30v-DC/1642370231?iid=202268212686
I also have an old HP one that only has a single output (The Instek has 2 variable outputs plus a fixed 5V output)
OK, well, I just thought you had a set up of some electronic stuff, on a panel, or something, with gauges, etc., and maybe a section of track, on which you did all of your electronic testing, from stall current to DCC.
Maybe I'm misunderstanding what the "electronics lab power supply" that you talk about, actually is.
Not really. Not too hard to work - typically there are 2 knobs, voltage adjust and current adjust. Pair of displays, one for voltage, on for current. Sometimes 4 - the set point and the current readings at the same time. Two modes - constant voltage and constant current. Constant voltage - the power supply will keep upping the current, to its limit, to make sure the output voltage remains at the set point as the load changed. Constant current - it will adjust the voltage up to the limits of the power supply to makew sure the current stays at the set point. Constant Current is how you test LEDs - set it to 9ma, and it doesn't matter what the voltage is set to, it will never deliver more than 9ma into the attached load. Constant voltage to test stall current of motors - as you put more and more load on the motor, it will draw more and more current, but in constant voltage mode the power supply will keep increasing the available current to make sure the voltage never drops. So your current will be the true stall current at a full 12V - since in a DCC loco, the motor is always getting full voltage, just in varying width pulses. You need to know the current when stalled at 12V.
Thing is, it wasn't on high. Since Thomas only came with a circle of track, no strights, he, or more often, Annie or Clarabelle, would imitate a classic Lionel O locomotive and roll right off the rails at full throttle. So speed had to be kept down.
A junk box I bought cheap (got some good useful stuff out of it that was definitely worth more than I paid for the box - a Tech IV, couple of nice locos such as an Atlas/Roco S2, couple pieces of rolling stock worth keeping, though much was Life-Like train set level) has like 3 of those type power packs in it. I'd give them away, as I have no use for them, but I really don't think they are a safe design. I have a Railpower 1370 (and now a Tech IV 220) for DC testing before installing decoders. Either one will do a better job of holding up 12V when stall testing the motor. Although truth be told, I can do all that with my electronics lab power supply, set it to constant volts, 12V, stall the motor, and read the amps right off it, no meters needed. I've already done that to test out the two locos I picked up since not having a layout, rather than dig out a power pack. It's very smooth DC, too, so it has no problem with a loco that already has a decoder in it (got one loco super cheap because the seller said it didn't run - only tested on DC, and the decoder was set to disable analog! Actually, it runs great.)
I still use one to power a test track I have set up for stall current testing. I can imagine if you left one of these on, throttle on high, for a long time, something would give!
These came with the different train sets that I bought through the years for the kids, like Tyco, Bachmann, and Life Like.
I can see why they are no longer allowed.
Certainly one advantage of the new unit is that it can be sold worldwide - just include the appropriate power pack for the destination country. The speed control unit itself remains identical.
That same type of pack was included with the Lionel G scale Thomas train I got my older son some 24 years ago. They are dangerous JUNK. It literally melted out the bottom, luckily did not set the carpet on fire. I wouldn't use one for ANYTHING.
Rich: Mike: I have seen the many on Ebay. Called Bachmann. The representative was cordial but declined any information other than a "Federal Government Regulation" prevents them from selling them. Advised me to purchase the new transformer/speed control combo. (@$90.)
Was just curious. Thanks for your replies.
Thanks for you
I did find a comment on the Bachmann forums that the pack was sold in the 1970's. I can see why a lot are on ebay. Not very good except for AC to operate twin coil turnouts.
Speed control is lousy with todays loco motors. A PC board with a series of contacts connected to different low voltage windings on the transformer. Couple resistor I think. The speed control picks up a contact.
Two forums, Bachmann and MRH, had photos of the inside but administrators pulled the photos.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
You might go to Bachmanns site and dig around, and ask in the forums. There are always plenty of them in Ebay.
While I was looking around, I read a post in the forums where someone had just ordered one, and it was dated 2013, not that this info has anything to do with exactly when they stopped making them.
Good luck!
Hello: Fast question....
Would you know when Bachmann stopped making the power pack HO/N #6607? (That is the older single unit which has been replaced by a transformer and speed control unit)
As always, many thanks.