TMCC Dash-9 (6-18252) sound unresponsive

Railsounds audio board is available from Lionel, so I have that option - https://www.lionelsupport.com/...p;resultsPerPage=150

I'm also going to see if another of my locos has the same RS audio board I could swap. My old K-Line big boy with TMCC/RS might have it but I need to check

The audio board will work in any RS4 locomotive, try it in another TMCC locomotive and see if it functions properly.  It can be either steam or diesel, it should work in any RS4 equipped locomotive.

Thanks, @gunrunnerjohn. The only other TMCC loco I have around that may fit the bill is an old K-Line Big Boy (3790-4015S). Do you happen to know if the RS audio board in that loco is the same?

It'll work fine, just pop your suspect board into the tender of the BB and see if it responds to serial commands.

I'll have to go the other way since the BB isn't functional at the moment, but I will try swapping boards and report back. Thanks!

This issue seems somewhat inconsistent. I was going to swap boards but figured I’d throw it back on the track first and see what happened. It ran totally fine! Then a day or two later I fired it up again and it was misbehaving. There was one instance where I was getting a lot of random crew talk when trying to trigger the horn and bell. I will probably try swapping the boards again, but any other thoughts?

Did you use a PLCC extraction tool and reseat the PLCC chips on the audio board?

Great suggestions here but since you said it started working again then stoped again try re-seating all the boards. Sometimes it’s a simple fix.

He reseated the boards, it's unlikely that oxidation set in so quickly.   That's why I'm suggesting reseating the PLCC chips, I find they are a problem more often than the board connectors.  The board connectors have a gold flash on the pins and mating connector, the PLCC chips are just tin plated, they're much more likely to oxidize after a few years, and the many I have fixed by reseating those chips bears that out.

I reseated both chips on the RS audio board with the PLCC tool but it didn't seem to help. I also swapped both the RS audio and power boards from the K-Line Big Boy I mentioned earlier in this thread. That also didn't seem to help. It doesn't seem like the R2LC would be the problem here since the loco responds perfectly to speed, direction, and coupler commands, but I'm going to try swapping that as well to make sure.

Any other thoughts or suggestions, please reply! I'll follow up with results

Thanks to all for the help so far!

The R2LC is the next step.  FWIW, the only use for the serial data out of the R2LC on that particular locomotive appears to be the sound, so if the serial data is corrupt or missing, the sound would be the only indication.

The reason that doesn't seem possible is b/c this loco has an ERR CC-M installed, with its serial RX soldered to the correct pin on the R2LC header. I guess it's possible that the issue is somewhere on the MLB between the R2LC output and the RS audio header? I will report back on the R2LC swap.

Actually, it's not only possible, but it's even more likely!  The forum is filled with stories about adding loads to the serial data causing issues with either the CC-M or the Railsounds.  I even built a special board just to fix issues like this!

R2LC Serial Data Buffer

The picture below is my new and "improved" serial data buffer that was an outgrowth of the above thread link.

If the R2LC swap doesn't do the trick, I'll probably have to try a buffer. I see you updated the board to use through-hole parts - great choice as many of us aren't very good at soldering I ordered a couple of the earlier version from you a while back and botched them both b/c I can't solder SMT parts to save my life

I do recall the CC-M feeling a little sluggish/unresponsive in the past while the sound worked fine. Maybe opening up the loco and fixing the antenna issue was enough to mix things up so that now the sound is having problems.

I converted the buffer design to thru-hole, and I also have offered them A&T for folks that don't want to solder them.

It's hard to say what is going on without actually seeing it, but what you describe seems serial data related.

I got a chance to work on trains today and swapped the R2LC with the one from the K-Line Big Boy I mentioned earlier - that seems to have completely solved the problem! I only got about 20 minutes of runtime so far but for all of that time the loco was running perfectly smooth and slow with the CC-M and sound was working perfectly. I can only hope this new good behavior persists

Thanks to all for the advice and helpful suggestions!

The other R2LC "may" work fine in the BB, give it a try.

I would but that loco isn't running anymore - it's a parts donor now.