Bachmann K4 with Soundtraxx TSU 1000

[Cooped]

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

[richg]

Remove the decoder and plug in the DC adapter. Hook up your multimeter using the DC amps option. Run the loco on 12 volts DC and do a current check.

Rich

[Cooped]

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

[richg]

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

For a current check, put the meter leads in series on one wire and the power pack. Look at the below link. Scroll to the bottom of the link. The light bulb would be your loco on the track and you can see the battery would be the power pack. Start with the highets amps scale.

http://www.allaboutcircuits.com/vol_6/chpt_2/4.html

Store the link in Favorites.

Rich

[Cooped]

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

[richg]

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

The Tsunami 1000 should not overheat if running at a normal speed for that loco. Have you run the loco with the tender shell off to see if there is any difference?  Just might be a decoder issue.

Rich

[Cooped]

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

[richg]

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

Right now I am guessing at a decoder issue. You could email SoundTraxx or try the Yahoo SoundTraxx group.
Any chance you have another TSU 1000 to try?
I and others have run these decoders with no temp issues.

Rich

[Cooped]

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

[richg]

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

All the OEM's to my knowledge have a open PC board design. No idea on how the components used on each "might" differ.
The shrink wrapped Tsunami seem to have a temp issue but all the temp issues I have seen so far are with the 750 Tsunami.
Another thing to try is to get some heat sink grease from Radio Shack and put a coating between the bottom, flattest part, of the shrink wrapped decoder and use small nylon ties to clamp the two items together. I get those small nylon ties at a hardware store. That has been suggested as well on the Yahoo SoundTraxx Group.

Rich

[Cooped]

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

[richg]

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

Confession is always good for the soul. lol
That could be the issue.
Use a fine tip conical 40 watt soldering iron and solder wick to clean up the mess. Then do a good soldering job. If this takes care of the issue, make sure to let everyone know in the other forums.
Check with your ohm meter between the two terminals. Rail pickup to motor lead has killed more than one decoder.

If you have a magnifier or Optivisor check carefully. A strand of wire might still linger.

Rich

[Cooped]

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.............

[richg]

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.............

Is this loco new from the factory or maybe modified by a previous user?
I have not run into a poor solder connection on a Bachmann but it may have happened.

Rich

[Cooped]

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.