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25 replies

Damaged Sound on Atlas-O SW

C ctrOGR Forum Member SUPPORTING MEMBERDIGITAL SUBSCRIBER

Today, I used an Atlas-O SW with TMCC and Railsounds to test the functioning of a MTH Z750 controller.

 

Everything worked the first couple of times that I ran the tested.

 

Then when I pressed the bell button, the sound system became very distorted.

 

Under TMCC command mode, the horn and engine sounds responded to TMCC Commands as did the speed and direction. But the very distorted sounds continued. There is no bell response. 

 

I did a reset; but nothing changed. 

 

Any thoughts as to the cause or the cure?

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Roger L.Roger L.OGR Forum Member DIGITAL SUBSCRIBER

Mike,

 

I have an Atlas NH SW1200 which went silent on me within the past year.  I tried re-seating the sound board, etc, etc, to no avail so i think it's the speaker.

 

How do you go about replacing the speaker?  Can you get at it from the bottom, or do you need to replace it from the top?  When I had the shell off, I couldn't see where the speaker was.

 

Mike CTMike CTOGR Forum Member
Originally Posted by Roger L.:

Mike,

 

I have an Atlas NH SW1200 which went silent on me within the past year.  I tried re-seating the sound board, etc, etc, to no avail so i think it's the speaker.

 

How do you go about replacing the speaker?  Can you get at it from the bottom, or do you need to replace it from the top?  When I had the shell off, I couldn't see where the speaker was.

 

Hood off, remove the screws from the motor mounts. Move the motor to the side, that should allow access to the two screws that hold the speaker in place in the fuel tank.  Remove the speaker mounting screws.  The Speaker can be lifted with the speaker wires.    Carefully solder wires to a new speaker and re-install.  Not an easy project.  Nothing with an Atlas SW is easy. 

 

 

C ctrOGR Forum Member SUPPORTING MEMBERDIGITAL SUBSCRIBER

Sounds like I need a new speaker. Lucky me!

The sound in conventional is very loud and there is no volume control. Probably a coincidence that it failed when I was ringing the bell.

I usually operate in command mode and turn the sound down immediately. So I have never had a speaker at maximum volume for long.

I will check with Bill Seratelli to confirm.

Thank you for quick response and analysis.

 

Has anyone tried using a diode in series with the speaker to reduce the volume?

Last edited by ctr
JohnGaltLineJohnGaltLineOGR Forum Member

I don't think a diode would work here, as audio is essentially AC current, so you would lose half the wave form.  You would also have open impedance on the output on that half of the wave, which may or may not be an issue depending on what sort of audio amplifier is used to drive the speaker.  You would probably be better off using a potentiometer, though that has it's own host of issues on the high side of an amplifier...

gunrunnerjohngunrunnerjohnOGR Forum Member SUPPORTING MEMBERDIGITAL SUBSCRIBER

If the locomotive has Lionel RailSounds, there is a provision for a volume control somewhere.  Pins 16, 18, and 20 on the RS4/5 board are the volume control, if it's hard-wired as high, you can cut the trace on the motherboard and wire in a volume control, it's a 10k pot.

 

If you have the new RailSounds board like the ERR RailSounds Commander, it has a volume pot on the board.

 

G GGGOGR Forum Member
Originally Posted by ctr:

GGG,

 

Have volume control in TMCC mode. Can't hear bell, #2 or #7 messages. But could be due to speaker distortion.

 

What do you think about using diode in series with speaker to reduce volume in Conventional Mode and protect speaker?

I think you get a better speaker or install or use the volume pot.  G

N NortonOGR Forum Member

Timely thread. I just picked up an Atlas SW8 with a dead speaker. It has to be the smallest speaker I have ever seen in an O gauge engine. About the size of a half dollar in diameter and thickness. The speaker measures about 11/4" but the fuel tank could actually accomodate one about 1 3/8". Anyone found a better speaker for these engines?

 

Pete

Mike CTMike CTOGR Forum Member

The speaker is under the electronics boards and horizontal motor.

Speaker.  This is an early SW frame, before TMCC and the speaker in the tank.  The tank has been altered to accept the wafer speaker.  Early SWs with Dallee electronics had the speaker in the hood under the radiator exhaust grills.

 Have fun with your project.    Note that even though it is a small speaker, the magnet is very strong, and will pick metallic debris from the track/track ballast area. Sometimes, just cleaning the metallic debris from the speaker face, will correct the sound problem.  

 Mike CT

Atlas speaker pictured is 30 mm X approximately 4mm.

Last edited by Mike CT
gunrunnerjohngunrunnerjohnOGR Forum Member SUPPORTING MEMBERDIGITAL SUBSCRIBER

I have a bunch of oddball sized speakers that I've accumulated over time.  Since I'm kinda' into upgrading small stuff with sound and command, I have my share of small speakers of various sizes.

 

For this issue, I'd look at the spot for the speaker and see if it can be hacked to fit an existing speaker.  If not, I'd go on a quest for the right sized speaker.

 

Mike CTMike CTOGR Forum Member

Speaker replacement can be a project, under the horizontal motor, and TMCC boards, which at the least would have to be loosened, and moved to access the speaker and the screws that hold it in place.   Speakers were available from Atlas. 

Part of the speaker problem is that the speaker volume is full, when the engine is first started, and usually has to be turned down.  IMO less volume would extend the life of the speaker, IMO. 

Last edited by Mike CT
D DMBXOGR Forum Member

I have a NP SW1200, all sound functions work but very low volume (at max TMCC setting).  It seems to slightly inceease a bit when running for a while but very very quiet. I tried resetting the reciever (AUI, 8) but no change. Is there anything else that could improve besides speaker replacement as I hesitate from recent experience to take these apart  ..

D DMBXOGR Forum Member

Thanks John, I think you are correct.  Oddly I let it idle on the track for about an hour and is gotten back to normal-ish sound (still not amazing, and less than any other I own) but I think I will live with it for now.  Could it be that sitting for a while and some component improved with use?? Anyhow if anyone else has this, give this a try as its way easier than taking apart an Atlas loco....definite PITA +++!

D DMBXOGR Forum Member

I hear you (pun intended)😜....but its still a nice loco, not gonna pull a giant passenger train either, but I will give Atlas credit, they did ok for such a small unit (circa 1999 by stamp on fuel tank)  I actually wish Atlas would re-run some diesels with their great tooling and not all these former MTH ones....which just are not 'Atlas O' in my books.

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