An update for everyone. I got the decoder back from Soundtraxx yesterday, they fixed a faulty diode. It now works a treat, no sign of any overheating.

For Rod, I'm trying to upload some pictures, didn't work first time so we'll try again. I used a loop of tape to secure the decoder and speaker to the tender sides. I had removed the weight at the front of the tender so these are put towards the front to go in that space. They need to be put as high up the sides as possible to make sure the shell fits snuggly back on the base. I had also removed the pcb board which gave more space at the back, but no need to remove that weight.

I trimmed down the plastic pieces that the screws holding the front weight were in and also trimmed down the rim of the circular area moulded in for a small round speaker.

I stuffed the wires into the back end of the tender shell making sure as best I could they did not block the screw holds to secure the shell back onto the base.

It's definitely a tight fit in there, especially with the size speaker I chose, but it sounds great!

Dan

Hi Rod

I certainly had to do some surgery and removed one of the weights. Even then with the speaker it was a tight fit. I'm on vacation right now, I'll have  a look when I get back to give you  a more detailed explanation of what I did. The decoder is at Soundtraxx right now, when I get it back I plan on tidying up how I had it fitted somewhat, shortening the rather excessive amount of black wire that is supplied in the tender for starters!

Dan

Got it to overheat tonight in the loco that appeared to run ok........... added aluminium foil heat sink, still overheated. Factory reset as suggested as a last resort by Soundtraxx, overheated. I'm done, sending it back to Soundtraxx, now all I have to do is get the dealer I bought it from to give me a receipt! Perils of buying at shows. Reputable dealer with a website etc so I don't think it will be a problem.

Dan

It was bothering me that I seemed to be able to run the decoder in another loco with no apparent problems. Having realized that the position I was able to fit the decoder was wedged in a spot where it was in contact with the metal chassis (probably a pretty good heat sink) I tried in another other loco this morning and it over heated. It certainly seems to be the sound that is the major culprit though. It was running fine just chuffing away, then I pressed function 2 for the long whistle and hey presto, over heat. I checked the speaker spec and it's 1 watt (8 ohm as said before) which ought to be ok right? It's sold by Railmaster Hobbies (DLG-8) for Soundtraxx decoders.

Dan

Had a response from Sountraxx who are recommending an aluminium heat sink with heat sink grease. Having run the loco for a while tonight I think I can see that although it overheats regardless of whether the lights or sound is on, but it happens faster and taskes longer to cool down with the sound on.

Dan

Don't worry Rich, I will keep everyone up to date.

As recommended by members of another forum I removed the PCB completely last night and hard wired the decoder. Firstly I was quite pleased with myself for just having done that, it being my first real soldering job. All ran fine for a couple of minutes, until ...... it iver heated again.

I was wondering then why it would work ok in one loco but not this one. The only thing I can think of right now is the position I had the decoder in the other loco it was wedged up against the chunky metal chassis so it could be I still need to work on a heat sink (it was out in the open air when I tested after hard wiring it in).

I'm going to contact Soundtraxx today anyway, see what they say.

Dan

It's supposed to be new from the factory and in looks to be in my opinion. I did get it at what I thought to be a pretty good price at the Greenburg show this weekend, but it was from a stand I have bought from before, a business rather than a private seller. I can't see any evidence of modification.

I meant the soldering from the factory is a bit of a mess, I haven't soldered anything apart from the speaker wires. Now, let me see.............

I have also just tried running this decoder, sound on in another loco and it went round and round quite happily with no problems, put it back in the K4 and it over heated. Hmm, loco issue??! Now back in the first post I did mention before I could run on DCC I had to fix a solder oops on the underside of the PC board. It was pins 4 and 5 where the solder joints were merged so left rail was going directly to the left motor, glad I found that before I smoked the thing! Anyway, could some continued voltage leakage be causing the excessive heating up? It's certainly a messy solder job on this board.

Dan

This is my first Soundtraxx purchase, other than OEM fitted in a little Bachmann 2-6-0 Alco and an Athearn Big Boy. I fitted an ESU Loksound and noticed this gets pretty hot too, but it's never had any overheating problems. I've never noticed any of the OEM fitted getting hot so I may open one up and see how it's installed.

Perhaps it is a decoder issue, I'll give the Yahoo group a try and then call Soundtraxx.
Thanks
Dan

Yes, I ran it with the shell off yesterday. It seemed it lasted a little longer before overheating, but hard to tell.

Hi Rich

ok, done that. Draw normal running is ~0.1A. Gently pressing down on the loco I got a stall current of 0.7A.

Thanks for your reply on the MRR forum also.

Regards
Dan

Will do Rich, thanks. I'm a bit of a novice though, do I simply place the multimeter leads on each track rail?

Thanks
Dan

Hi all
Hopefully someone can help. I bought a Bachmann K4 today and after fixing the solder short on the circuit board in the tender I fitted a Soundtraxx TSU 1000 and 8ohm speaker. Tight fit, but after some surgery it all went in. Ran fine for about 3 minutes until the decoder overheated. I then taped the flat side of the decoder to a metal weight in the tender to help cooling as recommended in the installation guide, still over heated. I then ran without the tender body on for max air circulation, still overheated.
Surely the motor draw in these K4s isn't too much for a 1A decoder?
Any advice would be greatly appreciated
Dan

Well me and the little guy had a great day. Got there in time to catch the end of the morning preparations with #90. #475 was steaming too for a while, but not running. Did the museum and the Choo Choo barn also.

Was going to get a bunch of pictures to postm but my wife too the camera with her on her trip.

Dan