DCC Specialties PSXX2 Circuit Breakers

PSXX Full Manual
PSXX Short Sheet Manual
PSXX Hints & Tips

PowerShield XX Series Circuit Breakers for DCC You can purchase your PSX Circuit Breakers in three configurations:

1. PSXX-1 DCC Solid State Power District Circuit Breaker, 1 Block, 0-10 Amps.


2. PSXX-2 DCC Solid State Power District Circuit Breaker, 2 Block, 0-10 Amps/Block.*


3. PSXX-3 DCC Solid State Power District Circuit Breaker, 3 Block, 0-10 Amps/Block.*

*The PSX circuit boards are scribed and milled so you can separate (for example) a PSXX3 into three individual PSXX boards if necessary.

The PSXX is designed to specifically handle low power starter systems:

• NCE Power Cab


• Digitrax Zephyr

The PSXX has a default trip rate of 2.0 amps

• The PSXX series has the most reliable operating features that protect model railroad equipment and wiring from damage during a short circuit, including fast-acting, solid-state electronics.


• The Power Shields are available in 1, 2, and 3 circuit-breaker models, allowing you to divide the output of a single booster into independent power districts.


• The PSXX circuit board is wired between the DCC system’s booster and the track bus.


• The PSXX includes screw terminals for easy connections from the booster and to the track. There is also an extra pair of terminals for linking the booster power input wires to additional PSXX breakers should you need to add extra PSX protected power districts.

The PSXX series is a product of Larry Maier's years of research and experience into problems dealing with false overloads that cause premature shut down of DCC Boosters and other Circuit Breakers. These false overloads are caused by large capacitors used in sound systems, decoders and lighted passenger cars. The overload appears as a short circuit until the capacitors are charged. The PSXX Series determines if the load is a true short or just an overload due to a discharged capacitor.                                  

• Advanced Circuit Design limits current to selected current value before circuit opens regardless of severity of fault


• Current Limiting will charge sound decoders without exceeding booster current capability


• Default Current Limit/Trip Current 2 amperes will work correctly for most layouts.


• Select Trip current values 1 – 10 in integer steps (1, 2, 3, …., 10) using CV 49


• Jumper Select Current limits of 1, 2, 3, or 4 amperes


• PSXX circuit boards are perforated with score lines so you can physically separate and divide PSXX-2, & PSXX-3 into individual PSXX-1 units if needed.


• Power On/Off by DCC: Turn on/off output track power with your DCC Throttle!


• Manual or Automatic Reset: Automatic reset: Breaker tries to reset every 2 seconds. Manual reset: Once the breaker trips, it remains off, ensuring complete isolation of the faulty block. The breaker is reset either by a switch or by a DCC command.


• All Solid State Operation: Fast, solid state design with reliable quiet action.


• Adaptive Load Reset: Electronically determines if the overload is a real short or due to excess capacitance in sound decoders or lighted passenger cars.


• Auto Stop with DCC Reset: A photocell can be connected to a PSXX input. Normally, covering the photocell will not cause any action. If the photocell is armed with a DCC command, the PSXX will turn off the next time the photocell is covered. A DCC command can restore the track power when desired.


• Photo Cell Controlled Block Power Off: Stop position control and occupancy detection for hidden tracks.


• Block Detection: Either a photo cell or block current draw can be used to detect a train in a block and to trigger a Block Occupied output. The current trigger level is programmable.


• Block Occupied Trip point can be automatically set to compensate for current flow in unoccupied block


• Very Low Voltage Drop: Total breaker on resistance is less than 0.060 ohms, so the PSXX has a very low voltage drop even at high currents. Better than detectors that use a diode voltage drop.


• Programmable Power Up Status: When power is applied to the layout, the PSXX can be set to always turn on, always remain off [power on as needed by DCC command], or to use the power status present when the layout was last shut down.


• Outputs for LED Indicators: Remote LEDs can be added to monitor the input/output power and the status.


• Network Feedback: Isolated outputs designed to provide Block Occupied, Block Shorted, and Power Status to a discrete interface for remote display or computer control. Will work with Digitrax LocoNet, NCE Cab Bus, ESU ECoS, and Lenz XpressNet interfaces.


• System Reset: CV63=42 sets all CVs and addresses to original factory values.


• Output for Audio Alert: An audible sounder can be added to the PSXX to provide an audible alert if there is a short.


• No Power Supply Needed: The PSXX uses the track DCC power to supply its operating power. Each PSXX draws less than 0.04 amperes.


• Easy to Install: With 4 mounting holes sized for a #6 screw.


• Flash Programmable: The PSXX firmware can be updated by Tony’s Train Exchange as new features become available or if older units need to be matched to a recent purchase.


• Discrete Input allows on/off control of track voltage for yard or other track section isolation. Compatible with any system that has a relay or isolated transistor control output including LCC, WiFi, etc. or can be used with manual toggle switch.


• 4 Indicator LEDs: Booster power (green), Block power (green), Block shorted (red), Block current limiting (blue)


• +5V and Ground Outputs for powering LEDs, no resistors needed


• Power On Status can be on, off (yard or staging sections), or status at power down.


• DCC Accessory command control on any Accessory address 1 – 2042.

Protected by U.S. patent numbers 7810760, 7810761, 7810435.

!!! DCC Specialties is so confident about the PSX's quality and performance that they are providing a 1-year "Goof Proof Warranty"!!!

The PSXX Circuit Breaker uses a new advanced design to provide a new level of over-current protection for your layout. Before the advent of the PSXX, all circuit breakers used a simple low resistance switch to turn of the current if it exceeded a set value. The layout is protected, but for the time between the onset of the short and the output switch turning off, the fault is connected directly across the booster terminals affecting all blocks connected to the booster. The booster will supply up to its maximum current trying to maintain the track voltage. Currents as high as 48 amperes can result, depending on your booster and wiring. The large current draw then means there is no current left for any other block even if they are protected by their own circuit breakers.

Customer Comments:

"I was having a new furnace installed and the furnace crew, while I was upstairs answering the phone, ran around in haste flipping every switch they could find in the basement to test out some electrical circuits. They turned on the railroad while all the metal items they dropped on the track were all over the place. Naturally, I had no idea the railroad was on, and it remained in a state of constant shorting for well over 2 weeks. I unplugged the system but wondered if it would ever work again.

You see, when my friend and I finally were able to reach the railroad system area to begin testing for problems, we fully expected all of Tonys Trains Powershields to be dead. We also expected the NCE system and booster to be dead. Upon turning on the system we found disappointing strange glowing lights, no track power, and no other signs of life. Eventually, we tried to reset one of those fancy computer circuit breaker multi plug in boxes that was used to plug everything in to. This test was met with a loud pop, a bang, and was complete with blue smoke. The thing was dead. After carefully testing each item out, all plug-in circuits, etc, we then came to the point where we could plug the system back in to a new surge protection strip. Much to our surprise the system not only came up, but all systems were working fine. When I realized that while one of those expensive computer surge protection boxes had taken a major hit, and that instead every single one of Tonys Trains Powershields, used to protect each town in the event of a short, had protected the railroad and all operating equipment, and had even survived themselves for well over 2 weeks of constant shorting."- Bob D.

"I received my new PS-X 4-circuit circuit breaker yesterday and installed it today in place of my existing 3-circuit circuit breaker. I purchased your new one because it was advertised as being able to handle the inrush current of sound-equipped locos, and it worked beautifully! I am using an NCE PowerHouse Pro system, and when a short-circuit occurred, I had to shut down the system using the Emergency Stop button on the ProCab. Disrupting to the operating session, to say the least! My 'acid test' consisted of shorting out the power district containing at least three sound equipped locos, removing the short, and watching the system come on automatically. This is EXACTLY what I have wanted for a long time (well, since I got into DCC). Thanks again." - Don M

"Figured I'd let you know. Got the PSX-AR and replaced the Digitrax AR-1. Took 5 minutes. The sound decoder that wouldn't make the loop before works perfectly! So, for what it's worth, at least with the NCE Power Cab, this makes a HUGE difference with sound decoders. And, it's definitely quieter and smoother with all my engines. Thank you." - Mike C. 

"I've seen a demo of one of the new 'adaptive' breakers from DCC Specialties that was nothing short of phenomenal. We had no less than 14 sound locos in the district - more than half of them older QSIs ... and it recovered from a quarter test short without having to roll any of the locos off of the track! The breaker just kept feeding the power "slowly" until everything was running normal. And it was a reversing section and it worked just as well when reversing. We just could not create a scenario where the breaker would fail to recover. So - if you've got one of those beautiful lighted Cal Zephyrs and an ABBA set of sound-equipped Fs to pull it ... this breaker will allow your layout to come back to life normally after I or someone just like me blows a switch. I know -you- never do this but you see I'm an old fart who can't see very well and so this happens more often than I wish. So, if recovering from shorts is a problem for you ... this is one suh-weeeeeet breaker!" - Jim B., California