Lionel legacy 2033600 static sounds.

I'd be looking at giving the volume control a shot of contact cleaner and running it up and down a few times first.  Check all the connections to the sound board and the speaker.  Could there be a bunch of little magnetic material stuck to the speaker cone, that will cause a fuzzy sound.  I had one that picked up a bunch of steel tailings from drilling, it sounded awful!

Thanks for the info on speaker, I'll check that and other stuff out. The volume control knob is consistent throughout rotation, no burst of extra static anywhere so not real sure but worth a try.

If the chip's connection were bad, what issues does the sound exhibit?

Was going to mention number boards are on as soon as voltage is applied, but it appears from searching, they are directly connected to track power. I hadn't noticed this on my two heritage engines from 23.

Looked over what I could. Speaker looked good, all connections look intact. Didn't try electronics cleaner yet, wasn't 100% where it would best be applied (photo with red mark is about the only place I see to apply.

Is this the sound chip in photo below?

Glad to remove shell, the black/red left front ditch wire was pinched between body and chassis.

I'll add that when operating volume control knob, static is consistent, gets louder and quieter with sounds as knob is turned. Turning counter clockwise, about an 1/8" from full stop, I here a 'click' in the speaker as the sounds completely stop, before full stop counter clockwise.

That's the Bluetooth chip

@Rod M. posted:

Is this the sound chip in photo below?

That is the bluetooth chip, the sound card is as below:

As a quick test, disconnect the Volume pot from the main board and carefully short 3V3 to the middle pin (VOL) with a flat head screwdriver, to eleminate the volume pot as the problem. If you still hear the static doing that, the amplifier chip (U5) is bad and will need to be replaced.
If you do find the static issue is still there, take the fuel take off and check if any of the speaker wires are touching the speaker frame. I had an AC6000 get its sounds messed up from that.

Ok, that board was standing vertically behind front motor.

The board you are asking about in your photo is a Legacy Bluetooth Board, not the sound board. 

Check my first reply for some tips to help troubleshoot the volume pot some more

@MichaelB posted:

That is the bluetooth chip, the sound card is as below:

As a quick test, disconnect the Volume pot from the main board and carefully short 3V3 to the middle pin (VOL) with a flat head screwdriver, to eleminate the volume pot as the problem. If you still hear the static doing that, the amplifier chip (U5) is bad and will need to be replaced.
If you do find the static issue is still there, take the fuel take off and check if any of the speaker wires are touching the speaker frame. I had an AC6000 get its sounds messed up from that.

Just getting ready to try your quick test. I've disconnected the plug for the volume control. Upon powering engine, I have sound at a level of what I assume is what the volume control was set to last time run. Sound is still static.

I haven't shorted volume to 3v3 because I wasn't expecting there to be any sound with knob disconnected. And if there should be sound, but it's still static, what is shorting the two pins going to do?

@Rod M. posted:

Just getting ready to try your quick test. I've disconnected the plug for the volume control. Upon powering engine, I have sound at a level of what I assume is what the volume control was set to last time run. Sound is still static.

I haven't shorted volume to 3v3 because I wasn't expecting there to be any sound with knob disconnected. And if there should be sound, but it's still static, what is shorting the two pins going to do?

From what I remember, with the volume pot disconnected from the board, it will default to 50% volume. So your result is normal, but the static still being there is not. Shorting 3V3 and VOL pins will set the volume to maximum.

From what I can see, you have a damaged amplifier chip. Since the static is still present with the volume pot taken out of the equation. I would check next if the speaker has the correct ohms reading (8 ohms from a multimeter) at the speaker connector and also check if each connection isn't shorting to the chassis

Thanks, I'll check speaker ohms.

I removed the plastic baffle on interior side and checked wires shorted to frame where they're routed between that baffle and frame, they appeared fine.

If it's the amplifier chip, on Lionel support, they don't show this specific rail sounds light board, but they do for several other sd70 and sd70ace engines. Would any of them work to replace this board and/or can the u5 chip be replaced itself?

@Rod M. posted:

Thanks, I'll check speaker ohms.

I removed the plastic baffle on interior side and checked wires shorted to frame where they're routed between that baffle and frame, they appeared fine.

If it's the amplifier chip, on Lionel support, they don't show this specific rail sounds light board, but they do for several other sd70 and sd70ace engines. Would any of them work to replace this board and/or can the u5 chip be replaced itself?

You can for sure go with the route of replacing the entire sound card, but that will be 100 dollars if you do. Replacing U5 isn't easy, since it it soldered on and you need to be extra careful to not damage other parts of the board with your soldering iron or unintensionally desolder other small components.

You could try unsoldering it and replacing it with a new component, if you are fully confident you can do that. If not, see if someone on the forum can help with this. I would be more than happy to do this repair for you free of charge, so long as you pay for shipping to me. I will also test it in one of my engines for 4 hours, if the repair is successful, before sending it back to you (I will gladly pay for return shipping too).

Also, see if Lionel will still warranty this item. They should replace the sound card free of charge and will test it out to make sure the issue doesn't come back.

Edit:
Also, when checking for shorts between the speaker connector and speaker. Please use the multimeter in continuity mode (beeping mode), checking from the metal part of the receptical to any screw on the frame (those will give you the best connection to the frame). If you see no short between any of the speaker connections and the frame, you don't have any of the wires shorting to AC ground

I recently thought I had a bad sound board on an earlier Legacy diesel.  Speaker measured 8 ohms resistance.  I did not measure to ground (my bad) and eventually found speaker clamp touching speaker terminal.   All I needed to do was rotate speaker slightly and tighten down.