What's inside those Power "Bricks?"

[peteski]

"Brick" is more of an electrical/electronics term than model railroad.  As he said, a "brick" is usually something designed not to be opened, just use it.  Another use is to say something, such as a mobile phone, is "bricked", meaning it no longer functions, and is usable only as a dead mass - a brick.

I understand the term "brick" very well when applied to electronic devices. I just have not encountered it for describing (still still functioning) model RR power packs.

[brill27mcb]

He seems to use a number of unique terms.  - Rich K.

[$2 Bill]

If you want to get Picky... UL etc list most as "Hobby/Toy Transformers" and list them with various Numbers as times or version change the Safety testing for them. (Now many UL and related Marks also have More Numbers to fight Counterfeits.)

Bricks Fits because of Shape of many units but yes, most sold as One Shot "Sealed" Units. If you return most under Warranty, the Company may look just to see the problem or it's Dead, Trash it or now treat as E-waist to keep Gov happy, then send a replacement. Business won't waist Time or Labor to fix many here even 30 - 50+ years ago. The Warranty Claim or Return to Store likely already cost them the entire Profit for 1 unit but Often the Profit for Many Units.

Some now or soon Power Packs in this Thread are Not Working and are more truly Bricks. I won't even test the "Tank" Power Pack above with those weird Metal Rectifiers and acid attack wires.

Some also uses "Wall Wart" Transformers or Switching PSU that is a "Plug on a wall" type or like many Laptops the PSU in the Cord still counts as "Wall Wart" to many as External PSU that's often Lost or Stolen when you move a whole house or just Travel.

E-noise is general Electric Noise of all Types and all Frequencies. In 300 case above it let so much Noise that all you hear on Radio is Noise. Noise from it, Noise from Train's motor and Noise from pick power thru the wheels, etc. Most Train Engine DC Motors didn't even have Small Capacitors on the motor for the same + behave as simply "Snubbers" when power shuts off fast for any reason. Many DC Engine still don't have them. Other Do to often meet FCC et al anti-RFI rules.

[peteski]

E-noise?  A 100µF aluminum electrolytic cap is not suited as a noise filter. If anything, it smooths out some of the 120Hz ripple after the bridge rectifier.  Back when that unit was designed, what you describe "E-noise" or RFI was the furthest thing from American model train designers minds.  Neither the power packs or model locos had any "E-noise" circuitry.

[$2 Bill]

Here's last of 70-80's Brick I have right now...

AHM Model 70203. While this is sold under AHM, I believe maybe sold under Different Brand and same unit but label for Canada with CSA Safety Mark only.

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Has a Safety Plug and Riveted Case.

Inside it's the same center tap transformer but with 2 Silicone diodes.
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While a Label on the Bottom claims...
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No fuse I could find. These all so far are made before "Micro fuse" etc but maybe/likely some of the wiring is the Fuse to Blow. I've see this done in other equipment and parts. (Same idea for Fusible Links for Vehicles.)
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[$2 Bill]

E-noise?  A 100µF aluminum electrolytic cap is not suited as a noise filter. If anything, it smooths out some of the 120Hz ripple after the bridge rectifier.  Back when that unit was designed, what you describe "E-noise" or RFI was the furthest thing from American model train designers minds.  Neither the power packs or model locos had any "E-noise" circuitry.

The cap did the job at the time plus smooth ripple a bit so engines crawl better. Not recommended for many, more so as a bigger cap some like will use can push DC out to Peak Volts not RMS Volts and burn up even some DC motors.

While most old power packs and motors for train engines and other parts didn't and still don't bother controlling noise... Often they ignore the issue and hope FCC et al won't notice when they cause RFI and other problem.

Many newer DC trains has various EMI/RFI controls. And Not just because there "DCC Ready" Models. Some "controls" are just a very small cap on a motor or larger cap and inductor(s) etc elsewhere in the body. Oh they might push PR spin that they care but reality likely Failed FCC Et Al testing without this.

Manufacturers of DCC Products seems many are doing the same ignoring because have Chips of Many Types from tinniest MCU to full CPU and related Glue parts then add Bluetooth and other Wireless all required to have FCC Testing. Example: In the US, Your PC or Tablet likely has Passed FCC Part 15A or B Noise Testing for a start then more FCC tests for Bluetooth WiFi or Mobile (Cell) uses to prove they only work in the correct Bands etc. Similar requirements for selling in other countries.

FCC Testing is often done by Approved 3rd Parties with manufacturers often costing Thousands of $ per day for the services.

[peteski]

I was aware of all the info you mentioned.   Growing up and being a model railroader in East European in the '60s and '70s I was was well aware of the European countries governments very tight control of the radio frequency spectrum and strict rules about RFI.

I also believe the only reason most (if not all) made in China models of American prototype locos made in the last few decades have the RFI suppression circuitry on board is because the same Chinese factory making models for European market (where the RFI laws are still strict) are also making models for American markets so they include the RFI suppression components in all models.  Like you mentioned, we live in times of a global marketplace.

And I still say that 100µF aluminum electrolytic cap installed on the output of a bridge rectifier has nothing to do with RFI suppression (what you call E-noise).

[$2 Bill]

This week moving to more recent models...

The "Infamus" Railpower 1300... Cheaply made but way better then the Railine 300 & Tyco 895. (Let's ignore the Rapido vs MRC "war" for now.)
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To take it apart, need split slotted "Security" tip. Many Security kits has them but can't reach 2 with deep holes so I use various "Dremel" tips and made one to fit out of a wreck screwdriver.
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Not Much inside to see here but does have real Power Switch unlike many other Bricks. The "Breaker" is a (P)PTC auto breaker. (P) is because Littlefuse and some other is PPTC not PTC. Note: There is Nothing holding the board or heatsink but the Case Sections when screwed shut.
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Since it's "Dead" I took the broad out to show the bottom.
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Schematic is common to many commercial and DIY PSU/Bricks. BR1 Trip Point is likely very small, < 2 Amps. TIP102 NPN 100v 8a but the Diodes are 200v 1.5a. Also it has "Pulse Power" but in the bare minimum way with just a Resistor to "Bypass" the Speed Pot.
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"The Wars..." Besides issues in other treads, The DCC Decoders may "hate" the simple "pulses" method used in the 1300 and some others. As Shown, The pulses are directly tied to the transformer then passthru any problems from the 120VAC side then "Slames" DCC decoder etc.  That's on top of have no Surge protection etc like all others list so far and more. Many Transistor "Bricks" may make 120VAC surges etc Worse because the Transistor can Amplify those problems causing larger spike etc in the Low Volt DC output.

E2A...
This is an O-scope trace of my "Dead" 1300... Believe it's "dead" for bad Speed Pot or Diode Set.
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What happen when the Pulses simply bypass the DC parts of units then you get "Full Power" of just Pulses.
While Peaks @ 17 volts (5v/div) on the trace and You see 6.4 Volts on the meter but likely No Current to run the Train Motors. If you leave the unit On with this problem then might damage the motor.

Might Damage DCC anyway of high Peak power for the 1300 and others covered in DCC Trains vs DC Power Packs.  https://www.therailwire.net/forum/index.php?topic=59608.msg822492#msg822492

[Point353]

This week moving to more recent models...

The "Infamus" Railpower 1300... Cheaply made but way better then the Railine 300 & Tyco 895. (Let's ignore the Rapido vs MRC "war" for now.)
(Attachment Link)

To take it apart, need split slotted "Security" tip. Many Security kits has them but can't reach 2 with deep holes so I use various "Dremel" tips and made one to fit out of a wreck screwdriver.
(Attachment Link)

Not Much inside to see here but does have real Power Switch unlike many other Bricks. The "Breaker" is a (P)PTC auto breaker. (P) is because Littlefuse and some other is PPTC not PTC. Note: There is Nothing holding the board or heatsink but the Case Sections when screwed shut.
(Attachment Link)

Since it's "Dead" I took the broad out to show the bottom.
(Attachment Link)

Schematic is common to many commercial and DIY PSU/Bricks. BR1 Trip Point is likely very small, < 2 Amps. TIP102 NPN 100v 8a but the Diodes are 200v 1.5a. Also it has "Pulse Power" but in the bare minimum way with just a Resistor to "Bypass" the Speed Pot.
(Attachment Link)

"The Wars..." Besides issues in other treads, The DCC Decoders may "hate" the simple "pulses" method used in the 1300 and some others. As Shown, The pulses are directly tied to the transformer then passthru any problems from the 120VAC side then "Slames" DCC decoder etc.  That's on top of have no Surge protection etc like all others list so far and more. Many Transistor "Bricks" may make 120VAC surges etc Worse because the Transistor can Amplify those problems causing larger spike etc in the Low Volt DC output.

Just a resistor, a capacitor and a Zener diode away from having the same circuit as in a Tech 7 780 power pack - aside from the power indicator.

[$2 Bill]

Just a resistor, a capacitor and a Zener diode away from having the same circuit as in a Tech 7 780 power pack - aside from the power indicator.

According to Schematic shown on http://www.sumidacrossing.org/Musings/files/140126_MRC_Tech_7_780.php 10Kohm at top of the drawing is same Pulse Power setup as 1300. Other parts mention have nothing for that. C1 smooths DC Ripple as peteski said about my old 300. D1 & 270ohm maybe try to regulate DC power or like just set max power to the Base of the transistor. 270ohm mainly keeps D1 from Frying.

If MRC claims D1 is for "Surge Protection" or whatever... Likely won't help much if any. Is only rated 1w 15ma

Not just that unit. Many MRC Tech __ models pushing "Pulse Power" hype are variances of the same often with minor changes like "Power Monitor" Light that's just wired across DC output.
Only 1 or maybe 2 so far that doesn't simply bypass the Speed Pot to have "Pulse Power" will be here later.

Is likely why many say later Tech series see no diff from Tech 2 or even worse depending on exact models involved.

But More confusing, even within Tech 2 etc... Models can be way different then others even when look the same or close to it on the outside. I'll cover this as well in future posts.

[mmagliaro]

I doubt MRC would claim anything about D1, or any other component.  They never comment about their circuit designs.
But D1 is clearly there to limit the top end voltage, which makes sure you never get 19v, 22v, or whatever
peaks out of the throttle, especially when it is lightly loaded.  Ironically, that is similar to the suggested mod I posted on the 1300
to keep its pulse peaks from hitting 25v under low load.

[$2 Bill]

You could mod a 1300 and others as stated to limit pluses...
But 780 10K bypass the D1 Zener and likely won't limit pulse power at low speeds. Need to see the trace of that output. LTspice etc doesn't like to emulate these packs so often doesn't match output on real O-scope.

780 C1 should makes output behave sim to Tech 2 1500 I'll post next. First I'll post 1400 because DC output is "in between" different versions with or without filter caps, the 470uF and larger.

[$2 Bill]

Here's the MRC Tech 2 Railpower 1400
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Inside it's similar to the 1300 and some others... Also switches On/Off 120VAC
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But they move the "pulse Injector" to the Speed Pot itself that is a custom part.
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Results is the Pulses don't go to "Full Power" when you "Crack the Throttle" but move up faster then main power. (5v per Div)
0%
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25%
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50%
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75%
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100% 13.4v on a "true RMS" meter but Peak is 18v a bit Higher then 1300 above.
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[peteski]

That is some nice vintage o-scope you have there.
My oldest is Tektronix 465B which doesn't even hold a candle to yours!

[$2 Bill]

Is a Tektronix 545A with CA Dual Trace plugin. On Tektronix Fixed Cart that have a drawer and space to store 2 plugins but don't have any extras.

This has way more features then I or most others can use. Also can heat a room if On for a few hours.