Pre DCS/DCC??

It's conventional control.  Ie. speed controlled by your transformer throttle/voltage.

Here's a link to it's Product page.

MTH Pennsylvania O Scale Premier 4-6-2 K-4s Steam Engine w/Proto-Sound 2.0
20-3125-1

Clicking on the Support tab brings up links to the Operator's Manual, Parts List, and Exploded Views.

The box says "Protosound".  This is PS-1, which precedes PS-2 and PS-3.  As a result it can only be controlled conventionally.  No DCS.

Mke

We run it conventional but we just bought a WTIU for our newer MTH and were wondering if QSI was a precursor to DCS and it would work, much like Lionel Base 3 operates TMCC if you will.  Then it got to a situation where we weren't sure if it was the engine or operator error.  Thanks for your prompt replies.

QSI Protosounds was originally available on some Weaver locomotives as a separate sound module that plugged into the mainboard.  When MTH was formed, QSI was asked by MTH to make the sound module integral to the reversing board and some additional features were added such as the coupler control.  The less said about how this arrangement ended between QSI and MTH, the better.  More importantly, with all original PS1 MTH it is recommended to replace the nicad battery with a BCR as a low or dead battery can scramble the sounds.

QSI still supplies DCC components and other electronics.

My AC-6 is a solid runner and can pull really long trains. 

@GG1 4877 posted:

QSI Protosounds was originally available on some Weaver locomotives as a separate sound module that plugged into the mainboard.  When MTH was formed, QSI was asked by MTH to make the sound module integral to the reversing board and some additional features were added such as the coupler control.  The less said about how this arrangement ended between QSI and MTH, the better.  More importantly, with all original PS1 MTH it is recommended to replace the nicad battery with a BCR as a low or dead battery can scramble the sounds.

QSI still supplies DCC components and other electronics.

My AC-6 is a solid runner and can pull really long trains.

Where do I find the battery portal on the AC-6 to do this?? Or does the whole top come off ?? Thanks.

You will have to remove the shell to access the battery.

You might find this helpful.  Here is a link to the original manual.  It's been so long since I had mine apart, I honestly don't remember!

Southern Pacific O Scale Premier 4-8-8-2 Cab Forward Steam Engine with Proto-Sound | MTH Trains

To further complicate matters, some early MTH products that are marked ProtoSounds use QSI components as mentioned previously but many later ones do not.  The QSI products operate similarly to a conventional locomotive, and many (most?) don't have a battery.  Some boxes mention QSI and some don't, and the instructions are often inaccurate regarding whether or not there is a battery.  Does your head hurt yet?

Later ProtoSounds locomotives that don't use QSI components work a little differently - there is a startup procedure that must be followed, along with a complicated process for setting / resetting various features.  This is covered in the manual.  If your PS1 locomotive has a battery, it is recommended that you replace it with a BCR before trying to run it.  (Search the forum for BCR - lots of info.)  Also, later PS1 units work better with some transformers than others - there's a list in the manual.