Mighty Sound of Steam Questions w/ Pics

here's a box and the instructions...$4 so far.

http://www.ebay.com/itm/LIONEL...;hash=item419630fd8c

Thanks Guys

I have all the packing but not the Instruction sheet.

There was no "wax" on the "pots" and I have been attempting to adjust for some kind of results......I just don't know what results I'm adjusting for

Seems to work well......it's just those "pots" that have me curious.

Whistle is okay........anyway to increase the volume?

Dave

There are many different versions of MSOS some have a single wire some have two and some have three. In my experience when the foam deteriorates the board just grounds out but I've never had one complete fry. The pots will adjust tone, no volume control there aren't a lot of steps in them so you have to make some pretty drastic changes in position to notice any difference. It looks like both of yours are set at about 11:00 which in my memory is the position I usually see them in when I initially open them up. I've been using the chassis body from a Milwaukee Special tender with my Southern Crescent so I could get a whistle which the Southern did not come with. I think it took me about an hour to tweak the pots so the whistle would sound different than my Milwaukee Special which often runs on the same display.

I'm not familar with the Berkshires but I believe they have a two wire tether and the chuff sounds and smoke puffs are controlled by a cam  on one of the drive axles that raises and lowers a lever pumping the smoke piston while also making an electrical contact which creates the static chuff. That's only a guess from looking at the schematics.

Don't know about the instructions but the schematics are downloadable in supplement 1 - 9 on this web page... http://www.lionel.com/Customer...e/service-documents/

Dave,

Thanks for the email.

the pot on the right, is the sound pitch for the whistle. Turning it to the right with a jewelers flat headed screw driver will turn the pitch sound of the whistle higher. Let it be.

This SOS board gets its power from the locomotive. The chuff sound on this engine comes from a ground strap on the tender that has an axle the has a sleeve attached to it, that when turning, strikes the switch and causes the chuff sound.

Hope this helps.

Thanks Matt

Two wires to the tender....the old postwar cam on the drive wheels to puff smoke.

Some sort of cam system on the one tender set of wheels for chuff I presume.

No pick up rollers.

I see now how those "pots" adjust tone and pitch of the whistle.

I just had to replace the speaker.......sounds went out and I thought I may have overplayed my hand fiddling with this.

Went to the speaker first......original and replaced.

I cannot read the Watts and Ohms on the original speaker...

Could you let me know what they are?

I replaced with an MTH PS 1 speaker and seems to work okay.

Dave

Thanks for answering back Mark

"Let it be"....best not to fiddle with it?

What is the pot on the left for?  It seems to have something to do with the whistle too.

However, I am not sure.

My first venture into this Mighty Sound of Steam....our trains have come a long way!

Dave

I have seen 8 and 16 ohm speakers.  Usually low watts at .2 or .5W.  Why fiddle with it if it works?  G

Answers:

The two pots adjust the frequency of two phase shift oscillators used to simulate a 2 tone whistle sound.  I believe the optimal frequencies are 440 and 746 Hz.  This copies the tones of the air whistle closely.  The reason for the phase shift oscillators is that they generate a sin wave, thus the two frequencies do not generate nasty nasal harmonics (non-technical terms). 

The sound of steam is created by a reverse biased npn transistor.  This generates what is known as Johnson noise.  It is amplified and sounds like a hiss.  It is pulsed by looking at the armature comutation.

Regards,

Lou N

G  ........... "Why fiddle"......it's just what I do..... 

I like to understand how something works .....then tweak it!

The speaker that I had to replace the original with is an MTH PS1 I had about.

It also has the "writing" on it smudged so I cannot read the specs.

Does 16 ohm.....5 watt on the replacement speaker sound about right and okay for this purpose?

Thanks G

Lou N

Thanks Lou for your post.  Very clear and most interesting.

I've been adjusting both pots.....carefully... and see how the whistle pitch and tone can be manipulated.  I'll Goggle a few of your terms to better understand.  

Although 35 to 40 year old technology...I find it very interesting.

Appreciate your input.

Dave

I think you are fine with the PS-1 8 ohm.  G

Here is the link to the instruction manual.

http://www.lionel.com/media/se...ents/70-8002-250.pdf

Link to parts diagram. Hope this helps.

http://www.lionel.com/media/se...ts/13100Complete.pdf

Thanks Gene

Very helpful.

Dave