Apparently RESET 18 has no effect over RESET 27 (chuff rate), but defaults everything else back to the factory settings. Based on my findings with multiple healthy PS1 engines. Sound correct?

By using reset 18.  From a PS-1 manual after the reset 27 instructions:

sinclair posted:

By using reset 18.  From a PS-1 manual after the reset 27 instructions:

 

NOTE: Special note for steam engines only. Once you have reached reset

18 you have two options. Option 1 resets all the reset features except for

reset feature 27 (Chuff Rate) back to the default setting. Option 2 resets

all reset features back to the default setting. For Option 1, press the

horn/whistle button once after you have heard the 3 clanks and 3 clinks

this will reset all the reset features except reset 27 (Chuff Rate) back to

the factory settings. For Option 2, press the horn/whistle button again

you have now reset the remaining reset feature 27 (chuff rate) back to the

factory setting. All the reset features now have been set back to the

factory settings.

Brilliant. I don't have this in a single one of my PS1 manuals. Thank you so much. CASE CLOSED.

MTH didn't always get all the info in the manuals for the Protosounds, as they were still tweaking it, until they went to PS-2.  Now here's the best part, the manual this came out of was for the PRR S-2 steam turbine, so it doesn't even have chuff sounds!

Code evolved over time, and manuals where cut and paste too much.  So editing doesn't always catch this stuff.  I have posted this info before, and folks have questioned that I was correct.  I have never used reset 27 other than at school when they trained us.  I just double select on reset 18. G