Lionel GE Demonstrator AC6000 sound card issues

Sure, maybe if you replace the amp IC, maybe it improves sounds on the current semi working sound card. The non-working sound card, again maybe but I've yet to see a Railsounds Lite style board fixed. In other words, I've seen a few dead ones, they aren't coming back to life. This is the nature of electronics sharing a common low voltage power supply- but source voltage is AC higher voltage. If any one part fails- that common low voltage DC bus potentially can cascade fail any and all other sections of a board.

Further, if you go down this path- I would test the sound card in conventional after the repair without first connecting serial data. This way, you cannot pass a failure up the serial data line into other parts- like your RCMD.

Again for testing, I would only connect power in, speaker, and vol pot. Again, for isolation and conventional testing, I would only plug in those 3 connectors.

I've replaced the amplifier and the bridge rectifier on those boards, those two are not too difficult as they're not the really fine pitch parts like some other parts.  I have actually brought a couple back from the dead from the very flaw you speak of, shorting a speaker lead to the frame.

I am coming back to this topic briefly to ask another question, as I will be going through with attempting to repair the sound cards soon. In regards to simple testing of the sound card, what needs to be connected for it to play sound? Just speaker and power input plug?

I want to attempt to revive both sound cards, including the completely dead one. So in testing each one I want to simply plug in enough recepticals to just make it play sound and give me an idea if my repair was sucessful

@MichaelB posted:

I am coming back to this topic breafly to ask another question, as I will be going through with attempting to repair the sound cards. In regards to simple testing of the sound card, what needs to be connected for it to play sound? Just speaker and power input plug?

@Vernon Barry posted:

Again for testing, I would only connect power in, speaker, and vol pot. Again, for isolation and conventional testing, I would only plug in those 3 connectors.

I would start out using a 9V battery as a current and voltage limited source (your could use a fancy supply or get serious and use meters to monitor voltage and current draw). Yes, while DC and likely to be seen as a horn/whistle or bell input, it's enough to power for a second and give sound or not give sound, and current limited enough to hopefully not cause more damage if something is wrong. Again, you are NOT plugging into the normal battery connector- you are instead using a battery to power the main power input connector "RET/3RD". Also, other details like the speaker is only the outer 2 pins of that connector- skipping over the middle pin that is not used. Also, in the volume pot, for max volume, just in theory connect 3V3 to middle pin VOL for max volume.

Got the parts today and have done the fixes

Gonna post some videos on how they perform in command mode too

Testing of both sound cards in command mode

Final command mode test with shell on

I will test it at my local club layout later in the month for a couple of hours and report back on if the sound card is still working good. I said 8 hours in the final test video, but it'll probably be more like 4-6 hours of testing

Haven't had a chance to to a shakedown test of the sound card yet, but I have another question. I plan to add in the ground lights that were not added to the model, at some point in the future. Once I know the sound card will be good. The main board already has the outputs functional for the ground lights (I saw 4.7 volts on the ground light pins for the main board when the ground lights commanded on), I just need to add 2 more wires for the ground lights to the lighting harness so the ground lights get power.

I plan to have the housings 3D modeled and printed to add them to the model, but I also need to get the wiring finished up. So I need the receptical type Lionel usually uses (including the types of pins I will need for the connector) and also what gauge wiring the lighting cord uses.

From the factory the location on the lighting board for ground lights (J3) doesn't have a receptical added. Although I could just solder on the wires for the ground lights directly to the pads instead.

Took the engine to my local club and ran it for 6 hours in total, sound card did not fail.

I will run it for another 6 hours in total another day, but so far the repair looks promising

Isn't it the greatest feeling when you repair/replace components in these electronic devils, and everything starts working again properly, and as they should, straight out of the box!!!!

Well done Michael!!!

Peter.....Buco Australia.