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We have a new 3rd Rail L-105 Locomotive, and in manual it specifically says not to use MTH Z-750 and Z-1000 transformers because they are cut wave transformers and will damage the electronics.  We have always run with a Z-4000 transformer.  Does anyone know if Z-4000 is also cut wave, or is it safe for 3rd Rail locomotives?

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This is really funny as TMCC and Lionel stuff is all chopped wave and thought to run better on it.  They may use higher peak if I remember correctly.

Z-750 and 1000 are electronic chopped with the 1000 typically a nicer curve if I remember right.

What typically is the issue is that Lionel likes a max of 18VAC track power and MTH transformer can deliver near 20 to 22VAC.  So you do not want full track power from a MTH transformer.  G

@GGG posted:

This is really funny as TMCC and Lionel stuff is all chopped wave and thought to run better on it.  They may use higher peak if I remember correctly.

Z-750 and 1000 are electronic chopped with the 1000 typically a nicer curve if I remember right.

What typically is the issue is that Lionel likes a max of 18VAC track power and MTH transformer can deliver near 20 to 22VAC.  So you do not want full track power from a MTH transformer.  G

Good info to know GGG, thanks.

Actually, if my 'scope isn't lying, all the Z-controller stuff, the Z-500, Z-750, and Z-1000 have pretty much the same looking chopped waveform, see sample below  The Z-4000, OTOH, has a synthesized pure sine wave and for all intents and purposes can be considered a pure sine wave as far as our trains are concerned.

Z-Controller Z-1000 Half-Throttle Waveform

Z-4000 Waveform

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I just had an old RK starter set engine on my bench that has the PS1 Allegheny board stuffed inside. I took the stock PS2 board out for another engine. No matter what I tried, I couldn't get past the 2 clanks with my Z1000 on my bench. The engine would not run.

I put it on the upper loop and controlled it with my Z4000 handle. The engine ran on the first try.

Very interesting and insightful information.  After I blew up my first PS MTH loco with a Lionel "Z" I learned the hard way about voltage spikes and went straight to a Z-4000 that I bought from Elliot Scher way back when through this forum.

The wave forms that GunrunnerJohn show remind me of the old MRC DC power packs where they had a pulse setting to smooth out the running of older open frame motor locomotives.  One could turn off the pulse for a full sine wave for more modern locomotives (this was in the 80's and 90's for me so modern is a relative term here).

To the topic, I use a Z-4000 for all my 3 rail and an old 180W DC power pack by PDH if I recall for my 2 rail.  The majority of my locomotives at this point are 3rd Rail.

Last edited by GG1 4877

Actually, if my 'scope isn't lying, all the Z-controller stuff, the Z-500, Z-750, and Z-1000 have pretty much the same looking chopped waveform, see sample below  The Z-4000, OTOH, has a synthesized pure sine wave and for all intents and purposes can be considered a pure sine wave as far as our trains are concerned.

Z-Controller Z-1000 Half-Throttle Waveform

Z-4000 Waveform

The scope outputs are good information.

The clipped waveform is worse than just a clip, which would simply limit the sine-wave output to a constant value during each (positive or negative) half cycle, and that would be a better input for the electronics. It looks like the clipped wave may be the initial part of the sine-wave (at each zero-crossing) with the power being regulated by the duration of the pulse. The clipped wave rises abruptly to near its maximum value and is composed of higher harmonics than the pure wave - possibly not good for the durability of the circuits that it's driving.

MELGAR

Last edited by MELGAR

John, you have to remember that there were several variations of controller over the years.  Bricks too.  Also, what the wave form looks like at various voltage matter too.

For PS-1 operation....not the original topic....I have seen folks have trouble with z-750, but not as much with z-1000.  Getting initial voltage low enough is important.  Remember PS-1 does not come out of INITIAL RESET state unless track voltage less then 10V.

As far as transformers blowing up PS-1, I have not seen that.  85-90% of the time it is a software conflict.   They do have  occasional faults with motor transistors, rectifier diodes and traces burning up.  I still have them come in with the wheels worn off the loco and the electronic PS-1 still working fine, even with white batteries.  G

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