Atlas GP9 Sound Issue

Check the speaker & its connections thoroughly.  It could also be a bad speaker. Those are usually 8 ohm speakers, check to make sure the resistance is around that value, anywhere from 7.5 to 8.5 should be okay.

What voltage is on the track?

The reason I ask, in the video if track voltage is low, then the railsounds power board may cut in and out. It sounds exactly like this is I'm starting my track at low voltage.

Otherwise, reseat the railsounds and power board on the pins.

Again, the other thing that happens is the daughter cards get loose and poor contacts on the pins of the motherboard.

Looking at the boards and no EOB. I’m guessing early production. I don’t know about the Geeps. But the early RS1’s had issues with the volume pots. I know on mine. A few twists back and forth got it working again.

Atlas is famous for bad speakers, so that's the first thing to check.  Next is the volume control, another weak spot.  Finally, reseat the two RailSounds boards and if all else fails, try reseating the two PLCC chips on the audio board with a PLCC extraction tool.

Thank you all for the feedback. So, taking the Gunrunner’s expert advice, I thought I’d take a look at that speaker. Its way down under the board package.  Getting to it puzzles me. Any one ever been there? Do you just pry it from the clips holding it? Looks like a screw could be holding the package to the loco’s frame. Are there more? If I remove it will she pop free? Love the loco and hate to blow it.

Larry

Start by measuring the resistance with a meter on the speaker leads.  Normally, if there's no sound and the speaker is bad, it's open.

How do you get bro the speaker? Its in the tank but covered by the board package. Are the boards screwed to the frame? They don’t seem to budge for me. Thanks for all the help.

Larry

Where are the speaker pin-outs? Just not familiar with the board layout.

Since I have no idea what board is in that specific engine, I can't really tell you where the speaker terminates.  Ditto about accessing it, though I do know that some Atlas stuff you have to take a lot apart to get to the speaker.

Go to. www.atlasrr.com.   Go to O scale and bring up parts diagrams and click on your model. Maybe of some help.  You should be able to drop the fuel tank with the speaker. Looks like it screws to the chassis. Maybe enough to identify the wires going to the speaker. The boards on the chassis should be mounted to a bracket that acts as a heat sink. If you can access the mounting screws you should be able to move it enough to fish the speaker wire through.

I don’t get into these that much. Anything I’m not familiar with. Take some pictures as you go along. Any questions on reassembly you have something to go by.

Guessing it has a TAS board. Go to the TMCC section of the Forum. You should be able to find some manuals regarding TAS or EOB installs.

Well, the picture is a TAS board, that's for sure!  Sometimes the screws are under the air tanks.

Fuel tank speakers with generic TMCC railsounds had/have two problems.  The speaker comes on at start up, full volume, which if it has a sound control pot, can be turned down. The speaker, (a large magnet), also picks metal debris from the track bed.  IMO, Mike CT.

Happy New Year. Good feedback, so thank you all. Seems like there is one screw holding down the mounting plate that is also a sink. If I can lift that package up it should expose the air tank screws. After the tank comes out, the tank screws should be exposed. Here I go. BTW; whoever designed this is a either genius or madman.

Larry

@Mainliner posted:

BTW; whoever designed this is a either genius or madman.

Realistically, neither. The tooling is an adaptation of the Red Caboose GP9, which had a horizontal motor instead of 2 vertical motors, and the motor mount was held in by 5 screws, 3 holding the fuel tank, and 2 holding the air reservoirs on. The fuel tank on the RC model just holds a weight, not a speaker, but if you need to take the frame apart, then the drivetrain needs to be disassembled.  

Atlas just dealt with the hand they were given. Combine that with the very large SAW board packaging of TMCC, and you've got what you have on your hands now.  

Honestly, screws is better than some of their other models, where things like air tanks are held on by fragile tabs.

I think I feel better…but encouraged

Found the problem. It was the sound chip. In checking out the recommended points, I noted that when I got around to what I assume is the sound personality chip the sounds came alive when putting mild pressure on it. I applied a bit more pressure and the chip further seated itself. After that I could the problem to repeat. So happy since I still have no idea how you get to that speaker. Tomorrow I will call Atlas and see if they know how to do it. If they have the magic answer I will post it. Thanks all for your help.
Larry

It's very simple, but you need an inexpensive tool.  You need a PLCC chip extractor, you simply pull the chip out and reseat it.  The contacts develop oxidation and need a new surface, it's a very common issue.

Don't try to pry the chip out without the correct tool!  You'll break the socket and then you need a new board.

Sweet. I ordered one and hope it can also help with that left molar of mine haha.