I installed a TSU-750 in an Atlas HO S-2 following the artical in the December 2010 MR and the decoder overheats and shuts off after about 5 seconds. I am pretty sure the motor is not the problem since the decoder overheats when it is just sitting still with the sound on.
Has anyone else tried this install and had the same problems? Is there a simple fix?
Thanks for any ideas or insight.
Jim B.
If not moving, you have another problem. Verify all the wire corrections are correct. Are you sure the motor is not locked up? The decoder draws very little current when sitting still and you are not giving a forward or reverse command. I use the 750 and the wiring instructions are very clear.
Did you put the loco on the program track?
I see you have one post so you must be new at this. There is a fix for overheating which the 750 is known for but you have another issue.
The Yahoo SoundTraxx group has discussed this issue a lot. Attach the decoder to a piece of aluminum with a film of heat sink paste between them.
Rich
Look at the below link. Look at all his DCC stuff. Store the link in Favorites. You will need it.
http://www.mrdccu.com/curriculum/soundtraxx/tsunami.htm
Rich
I put a Tsunami into a Mikado tender. I also noticed how warm it was, just sitting there idling. These decoders just run hot. In the tender, it has some room for air circulation, but I’d suspect that confining it in a diesel body would be a problem.
Can you arrange for some air circulation? Perhaps upgrade the shell by adding see-through fans or grills?
IF, and I say IF, the voltage from the command station/booster is a bit on the high side, the Micro Tsunami WILL get hot just sitting there!
I had to lower the output voltage on my layout to avoid killing sound decoders.
What voltage were you measuring before and after you did this? Were you just using an AC voltmeter to check it?
What was your input power supply voltage, and how did you reduce it?
Finally, did you notice any problems with the lower voltage?
The motor is not locked up, I checked the loco before the install. It runs very smooth and draws less than .5 amp.
I am using an NCE Power Pro system.
The decoder is wired correctly, per instructions and it actually works properly for a few seconds, then it shuts off and the headlight blinks 9 times, indicating an overheating issue. It shuts down regardless of if the motor is running or not. The LED on the decoder remains lighted even when the loco is shut down.
This is not my first decoder, just my first TSU 750. I chose it because of space limitations in the HO S-2. I was wondering if others have had this problem.
Thanks
Jim
I have seen the overheating shut down before. But it usually take several minutes of running before it shuts down.
I would remove the decoder and hook it up to a known good test motor. See if it will run without shutting down. Check the lighting, speaker ohns? Change speaker for a test?
When possible I mount the TSU-750’s on a heat sink. I have had to do this when using the TSU-750’s in HO models. But even without the heat sink the models would run for 5 to 10 minutes before they shut down.
When you check the amp draw of the motor are you stalling the motor with about 16 volts applied?
Motors will draw a bunch more amps on start up than when running. Stalling is one of the best ways to test for amp draw.
If all else fails, change the speaker, and make sure it is an 8 Ohm and not a 4 Ohm speaker.
Does the Power Pro cab have the capability to show track current?
My NCE Power Cab does have the track current capability. I have used it.
What is the AC voltage reading on the track? My digital voltmeters show 13.6 VAC and that agrees with my DCC voltmeter and 'O Scope readings.
Rich
I have a transformer that has a output of 15 V (60Va). The track voltage was checked with a RRAMPmeter (from Tonys), and it was 22 volts on the tracks (square wave equalized). I made a rectifier circuit with 4 rectifier bridges (2 in each wire to the tracks). After that it lowered the voltage with 4,2 Volts.
I have seen no adverse effects after the modification. All decoders are cool to the touch now…
I also installed the Tsunami micro 750 in an Atlas S-2. The speaker I used was an 8 ohm mini oval with a QSI brand sticker on the envelope. I replaced the headlight bulbs with LED’s. So far, I have had no problems. I also have an NCE Power Pro system. My track voltage is somewhere around 13VAC (but not below 13VAC) when read with a Digital Mulitmeter on the AC scale, as far as I can remember.
I didn’t follow the article closely because I am an electronics technician, so I did it the way that I am used to doing electronics work.
I’ve had a couple Tsunami’s exhibit this. Lowering the track voltage did help. I also found that if I ran them with the shell off, they would last longer before shutting down. If I blew on them, they would last even longer. Obviously none of those answers solves the problem though.
Mine went back to Soundtraxx, and the replacements work just fine.
Mark.
22 volts on the track? Wow, you could fry 1:87 scale eggs on your locomotives with that much voltage. The recommended voltage for HO is in the 12-14 volt range. I’m not surprised that your decoders were running hot.
Actually, most DCC stations put out between 18-20 Volts. The RP for DCC voltage says that it is allowed to have 22 Volts to the tracks, but that N-scale would require 16-18 volts instead. I don´t see why HO couldn´t have the same standard…
Maybe most DCC stations made by Lenz and sold by Atlas, most US ones put out about 15 volts on the HO setting, if they have one, or generally between 12.5 and 14 volts for ones without settings. Spec or not, 22 volts is way high for HO and smaller scales. Maybe for G scale it’s ok.
–Randy