MTH K4s (original Protosounds) using Lionel ZW-L

Original Protosounds was designed to work with pure sine wave transformers, like most postwar Lionel transformers and the Z4000. Original Protosounds will not work with chopped sine wave transformers, which all new Lionel transformers are. 

ProtoSounds is a MTH adaptation of QSIndustries electronic reverse and sound systems. All were designed for postwar transformers that produced "pure" (full wave) AC. Modern transformers like the ZW-L produce "chopped" AC: the crest of AC "waves" are cut off.  When these transformers came on the market in the 1990's, MTH and QSI customers complained that their locomotives wouldn't run. QSI manuals listed compatible and incompatible transformers.

MTH designed the Z4000 for QSI systems and even included a PROGRAMMING button for QSI /ProtoSounds features.

ProtoSounds and QSI products are designed for "conventional" operation with transformers that produce "pure" AC. They can't "read" or "digest" "chopped" AC. There are a few exceptions, but "chopped" AC will damage or "fry" the boards eventually.

PS-2 and PS-3 are more tolerant of "chopped" AC. But an upgrade may eliminate some PS-1 sounds.

Jim R,

   Simply use an old KW or ZW Transformer, with 10 Amp Resettable Breakers or a Z4K and your P1 MTH Engine will work just fine.  

PCRR/Dave

Thanks guys. I thought it was likely the wave signature of the ZW-L.

Since it is a club layout, Dave, I probably won't be able to pick what transformer I use, but with this information, I might convince the club to keep at least one of the layouts, of the 11, hooked up to a Z-4000. The club actually just replaced the Z-4000s with ZW-Ls this month, and some of the Z-4000s are still on hand. Obviously, most guys aren't running original Protosounds anymore at the club, but there may be a few. This info helps.

Some of what was said above is not accurate.  EARLY QSI and MTH units DO require pure sine wave so that is probably your issue.  Later QSI improved the design to work on modern transformers and even had a reset state for selecting transformer type.  Later MTH starting around late 1996 could work with modern transformers.  I run my MTH PS-1 on ZW-C, Power Master, and a K-Line (CW-80 like) transformer and they work fine.  BUT, early stuff can be an issue, and sometimes component tolerance change (capacitors and such) and engine won't respond right on certain modern transformers.

Basically hit or miss.   G

This is good to know as I have one older MTH PS-1 engine and a Weaver engine with QSI sound system. So my older transformers are good to use with PS-1.

I can't afford a new transformer at over $650.00 for one so I am sticking with post war transformers like the ZW & KW with added on circuit breakers and TVS units.

Lee Fritz

As I stated in your friend's thread, try putting a lighted caboose or passenger car in the same power block as your PS-1 locomotive, and it should leave reset.  Once I started doing this with my PS-1 locomotives, I've never had a locomotive not leave reset on any of the non-pure wave transformers people claim they won't work on.

Sinclair,

   Which lighted Caboose works the best, Lionel, MTH, Atlas, list a few for us to know exactly which one's are getting the job done for you, when running the P1 Engines with the ZW-L.  Remember however if you do this near your Legacy you could have other problems with it, and can they be LED lights in the Caboose.  Note the unlighted Caboose in the picture that now runs at the end of my Legacy controlled Christmas Box Car Train.  Was pulling the light Weaver Shriner Caboose and it totally killed the Legacy Signal. Further will the Search Light Car accomplish the same running stabilization as the lighted Caboose for the ZW-L/P1 Engine combo.

PCRR/Dave

Sorry, Sinclair. Adding the five lighted passenger cars made no difference. 

Jim R. posted:

A friend tried to post a question on my behalf, but mingled it with a question of his own, which complicated the matter. So, to simply, I'll restate the question I have.

I recently began running an MTH Premier K4s, which is equipped with original Protosounds and a BCR (in place of the original NiCad). The engine runs fine using my MTH Z-4000 transformer. I simply charge up the BCR for a minute at 10 volts, turn the throttle down to under 10 volts, and then take it out of reset with a push of the direction button. No problems whatsoever.

But when I took it to my club to run on one of the layouts there equipped with Lionel ZW-L transformers, I couldn't get it out of reset following the same procedures. No matter what voltage I use, I get the "Clang Clang" signal -- but thankfully not the "Clang, Clang, Clang" -- and the engine stays in reset or neutral.

I took it home again later that night and again ran it on the Z-4000 again. Again, no problem. It ran perfectly.

So, can anyone here tell me whether original Protosounds and the ZW-L simply don't play well together? Any solutions? Would an upgrade to PS3 make a difference?

It's too bad you couldn't trick the engine , Start it up with an old lionel pure wave transformer or Z-4000   and run it out to the main controlled by the Lionel  L.  .  Should be good until next  power down.

Jim R,

   This is why I wanted Sinclair to advise you of just which Coboose he found that actually made the difference, for some reason it does matter, some work some do not.  For this reason I gave you the advise, to use the different transformers that actually cured the running problem.  

PCRR/Dave

Where they LED?  All mine are still incandescent bulbs, so I never thought about testing with LEDs in the cars.  And no, it didn't matter the brand, but I can say most of my lighted cabooses and passenger cars are MTH.  I have not had any issues with my Legacy signal.

There can be a lot of variables in the PS-1 electronic and the Electronic Transformers that allow one to work and another not too.  There have been plenty of folks that have an issue with early PS-1 and certain transformers.  Despite lighted lock-on and cars.  The manufactures, both QSI and MTH had some warnings and QSI modified the board.  So I doubt a simple bulb solved everyone's problem.  Otherwise why modify the electronics?  G

One thing I've found to damp the effect of the sawtooth waveform from electronic transformers is a 10uf 50V non-polarized capacitor across the track feed.  This seems to have a very beneficial effect in most cases.

I changed out the sound chip and it fixed the problem for me.  I don't know if anyone else here has tried that. I got the chip from a RK K-4.

I like GRJ's suggestion.  I've never 'scoped the waveform of a ZW-L, but based on our club's experience with Powermaster PM-1's, I suggest at least 100uF, especially if you want the sound to work (chuffing speed may be off though.)  Some of those early PS1s are pretty finicky.  Also, put the cap in a ventilated metal enclosure.  Because it will get hot, and you don't want to be near it if it bursts!  -Ted

Thanks guys. Obviously, I don't want to force the club to make changes on my account, especially when I have other options. But this info will help me decide how to manage my future home layout (aside from my 3 x 8 foot O27 layout) for the broad mix of Lionel, MTH, K-Line, Williams and other large locomotives I have. 

gunrunnerjohn posted:

One thing I've found to damp the effect of the sawtooth waveform from electronic transformers is a 10uf 50V non-polarized capacitor across the track feed.  This seems to have a very beneficial effect in most cases.

John, wouldn't that defeat some of the slow speed startup capabilities of a chopped wave form? Thinking it would make a square wave look more like a sine wave?

Not really.  It doesn't do much to the waveform, it just rounds the edges a bit and knocks out the higher harmonics.

gunrunnerjohn posted:

One thing I've found to damp the effect of the sawtooth waveform from electronic transformers is a 10uf 50V non-polarized capacitor across the track feed.  This seems to have a very beneficial effect in most cases.

Make sure you read GRJ's post carefully.  The part NON-POLARIZED is essential.  So is the value, 10uF.  When Lionel made their first solid state transformer (MW?) the output driver was a triac.  I used a much larger capacitance value and it causes the triac to loose its mind and turn full on.

I had this experience recently running a friends Williams GP30.  The TruBlast plus has a large input cap that, once again, caused the loco to go full runaway.

Heed GRJ's advice given above.

Lou N

You're right Lou, I guess I should have put non-polarized in bold and italics.