Skip to main content

A few months ago, I was watching one of Benz Trainz videos where he used an inexpensive DC power supply for his 0-gauge trains. I was intrigued, so I bought one like this: a YUNBO Adjustable Voltage Power Supply Adapter AC 100-240V to Variable Voltage DC 3-12V 5A 60W.

mceclip0

This worked well for a little while, but the 5-pin, B5K on-off potentiometer is not very robust, didn't last long, and I discovered that it is really a PITA to replace. The enclosure was not easy to open, and after an extensive web search, I realized that the pot is a real specialty item, with a long shaft, 3 long pins and 2 short pins for direct mounting on a PCB. I wasn't able to find a replacement, so I just bought another power supply.

However, I thought I'd do a little experiment to see if I could repair the old power supply. So I opened up the case (not very easy), and desoldered the pot, which is physically connected to the PCB via the 5 pins. I wired-in a new SPST rocker switch and a new 3-pin B5K pot with connections to the PCB.

It works!

See the picture below for the hasty, experimental setup. The red and black wires from the switch are routed through the pin openings and are soldered to the terminals at the backside of the PCB. Likewise for the blue-green-yellow wires from the new pot.

Eventually, I will install all of this is a new enclosure. The remote switch and pot configuration will allow for an easier replacement the next time either of these components fail. Hopefully, the power supply will last longer and will be more reliable.

PXL_20230304_201743805

Attachments

Images (2)
  • PXL_20230304_201743805
  • mceclip0
Last edited by Mossback Mike
Original Post

Replies sorted oldest to newest

@romiller49 posted:

Why not just use a HO power pack.

Rod - That is worth looking into.

The power supply that I described in my original post, costs $19.95. That's pretty affordable. Recently, I have been putting train sets together for my grandchildren, and the children of my nieces and nephews. I have been buying old Lionel and Marx stuff from the bargain bins at the local train shows, fixing it up and sending it off - usually with one of the cheap $19.95 power supplies, or with an original Lionel transformer - if I can find a working one at a reasonable price.

Rod - That is worth looking into.

The power supply that I described in my original post, costs $19.95. That's pretty affordable. Recently, I have been putting train sets together for my grandchildren, and the children of my nieces and nephews. I have been buying old Lionel and Marx stuff from the bargain bins at the local train shows, fixing it up and sending it off - usually with one of the cheap $19.95 power supplies, or with an original Lionel transformer - if I can find a working one at a reasonable price.

Mike, I get these HO power packs at train shows for $15.00 or less. The accessory terminals are AC approx 17 volt and the variable side is DC volt 0-13

Attachments

Images (1)
  • image

@Mossback Mike, I'm not the electrical expert as are a few others on this forum (who I have learned some things from), but I do run my layout on DC current. My reason for this was quite accidental. While adding weight to a 1990's era Industrial Switcher with a DC can motor, I shorted the circuit board reverse. Well, without the circuit board I could add easily add more weight, but to have forward and reverse operation, I'd need to have DC current.

In the early 1990's, Lionel made a rectifier box for the purpose of using a normal Lionel transformer to run their line of G gauge trains that ran on DC current only. So I made my own version of this, adding a heat sink and air slats in the housing for ventilation.

I use a Lionel 1033 transformer which has the unusual feature of differing voltages to the track. The B-U setting of 0-11 volts is perfect for the modern era starter set variety of engines which have smaller truck mounted DC can motors. Whether in sets or as individual sale, these locos were advertised as being AC/DC compatible.

I at one time had experimented with the HO power packs mentioned above. Most of the black box/red handle variety (also the kind that came in the DC only starter sets) have a starting voltage of 6 volts, which makes these locos take off like jack-rabbits. Bachmann had a nice little DC power pack which I tried, BUT these DC power packs DO NOT have the amperage to run much more than one of these starter set locos and maybe one lighted caboose. Add more to the track and the power pack trips. It certainly wouldn't have the power to run an open frame AC motored loco or probably a loco with larger vertically mounted DC motors.

There are also some other liabilities using DC current. There are some Lionel locos, like with "Trainsounds" where you will ruin the circuit boards if you run them on DC current.

Engines with AC motors, like the ones seen in your video Mike, will also get HOTTER much quicker on DC current... this is something to be well aware of. I've read about this on the forum and it is indeed true. You could warp the plastic shell on your engines (those that have plastic versus die cast). I can't imagine getting so hot is good for the engine motor either. So I run MPC era locos for either shorter stints, or I have my layout set up to go back to AC current to the track and will run locos with open frame AC motors on AC.

The heat factor is also true of accessories with solenoid activation, like a crossing gate. I run my not off track power, but off secondary DC power (no buzzing noise) with a momentary push button for activation. At one time I had one wired to a toggle on/off switch so I didn't have to hold while the train passes. Once, I inadvertently left it on, and it didn't take very long to overheat and burn out the solenoid coil. Again, be forewarned of this. Normally I don't activate a crossing gate every time a train passes. So DC current for occasional operation like this is this is fine, just make sure you use a momentary button.

Also some operating cars will NOT operate on DC current. I have the post war operating merchandise car, operating milk car, and operating barrel car: All operate fine on DC current. The solenoid driven operating search light car does NOT: The light housing does not rotate. This is true of the postwar Lionel and the modern MTH versions.

Another liability which I've read about on this forum, is that DC current seems to attract dirt and grime to the rails. One of the electrical experts here explained it, but I couldn't repeat it. I do know though, that it is true. I clean my track a little more frequently on DC current than I ever had to on AC current.

But I find the types of locos I have run more smoothly on DC current, and with the smaller locos, not having the circuit board inside allows more room for added weight, so those locos not only run better but can pull a decent length train.

Last edited by brianel_k-lineguy

@Mossback Mike, I'm not the electrical expert as are a few others on this forum (who I have learned some things from), but I do run my layout on DC current. My reason for this was quite accidental. While adding weight to a 1990's era Industrial Switcher with a DC can motor, I shorted the circuit board reverse. Well, without the circuit board I could add easily add more weight, but to have forward and reverse operation, I'd need to have DC current.................



Brian - Thanks for the tips. I checked out your repaint thread. Amazing workmanship. IRT the power supply, I am probably just going to end up using it for accessories. I certainly have enough Lionel transformers kicking around for my old trains. However, I spent $19.95 on the variable voltage DC power supply, and it didn't last more than a couple of months - so I have to get my money's worth. That's why I decided it might be fun to try and fix it.

If you have an old PC Tower laying around not in use, take out the power supply unit and use that for a DC Power Supply. They have 3.3, 5, 12 volt outputs, some have a -12 volt output. You could put a pot in line on a output so you can have a variable power supply. If you use +12 for your positive and do have -12 also, use that for your negative and you can adjust with a pot from 0 to 24 Volts. I'm not sure what pot you would need. I use the 3.3, 5, and 12 volt outputs on my train layout for DC Accessories and Lighting.

Very nice gunrunnerjohn, perfect for the professional technician like you who needs and demands accuracy with all the complex projects you make in advances to our train hobby. I figured it was probably way out of my price range, not bad at all, only $69.99 on the A website, I thought it would be much more expensive.  Unfortunately all our medical issues, appts, testing, meds, and travel to the big city for our care come first.  That's why I only have a fairly small conventional power layout with starter set trains. But I can dream can't I?😁

Last edited by Gary P

I use them for powering projects on the bench as well as testing smoke units, etc.  For most uses, they're probably overkill, but I really like them.  I've checked the accuracy of the voltage and current readings, and once you get past about 10-15 milliamps, both meters are spot on.   I really like the wattmeter feature, as well as the current limit.  They'll either trip on an overcurrent or go into constant current mode, that's programmable.  There's also an upgraded model with a computer interface to set parameters and read back the status of the power supply.

Add Reply

Post

OGR Publishing, Inc., 1310 Eastside Centre Ct, Suite 6, Mountain Home, AR 72653
800-980-OGRR (6477)
www.ogaugerr.com

×
×
×
×
Link copied to your clipboard.
×
×