# TSU-750 vs TSU-1000 heat...?



## Brakeman Jake (Mar 8, 2009)

I have two Athearn articulateds that had their coal loads cave in thanks to MRC decoders that had started to melt before I noticed.They've since been replaced with TSU-4664N decoders that ran just fine when I tested them.Locos are now stored until layout is functional.

I just purchased a Spectrum 2-8-8-4 that I'd like to add sound to.It has a quite large tender so that a TSU-4664N would be an easy fit if I could find the special connector wich seems to be Athearn typical.

My other option is a wired decoder like the TSU-750 wich is a pretty hot runner and that's bad to me.Soundtraxx say the decoder can handle it wich I believe.However,it's the costly plastic around it that worries me.

I measured the inside of the tender and found that a TSU-1000 would likely fit in there.My question is this...will a TSU-1000 run hot too?What causes the heat?Is it the traction power or the sound processor?I'd hate to melt another tender.


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## NIMT (Jan 6, 2011)

The TSU-4664N decoders are discontinued and I don't know of anyone that has any stock anymore.

Traction power is where the heat comes from.
A TSU-1000 does run the same heat wise it just seams less because of the larger heat sink area.
One option is to add another heat sink( a strip of aluminum works great) to the TSU-750's, to get it to spread the heat out better.
that ran just fine when I tested them.Locos are now stored until layout is functional.
FWIW: I have never melted a tender or engine with a TSU-750, I do know it's a fair amount of heat but it's manageable.


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## Brakeman Jake (Mar 8, 2009)

I've installed a TSU750 that I purchased from the LHS (gone since) over three years ago and the sounds all work right.The only problem...rear light turns on (dim) as soon as track is powered.It does turn on full when loco is backing up though.It seems I crossed some wires wich I can't see,or the decoder is defective or it's the original PC board that does this,although everything was normal with the original Lenz decoder.Could it be a programming feature I don't know about?


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## NIMT (Jan 6, 2011)

No sadly that's a sign that the decoder is damaged, if you send it to me I think I can get it fixed for you.


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## Brakeman Jake (Mar 8, 2009)

Sean,thanks for the offer,you're most helpful as always.The decoder,except this defect,is absolutely perfect...all features work and it programs easy so I just cut the yellow wire.I don't mind not having a rearlighton a steamer anyway.

I chose to spend my efforts making an airtight speaker enclosure in such a tight space and got good results...sounds are quite nice even without the tender's shell.

The next chore is designing a heat sink to glue to the decoder that will fit inside the tender...not much spare room there...just another challenge...love it though.


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## rrgrassi (May 3, 2012)

Use some thermal paste instead of glue. Glue can block the heat transfer to the heatsink.


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