Presuming your installer did a good job, I would send the decoder back. Most likely the problem is with the decoder. As others have stated it is very unlikey that your shay is drawing anywhere near .75 amps. Of course a stall test with a ammeter will confirm this, but in my experience the modern offerings from spectrum all run under the draw that Cacole describes..
Gluing the decoder to the shell is not a good idea for lots of reasons, mainly being that it will be hard to remove the decoder if the idea doen't work. The protective wrap around the decoder is part of the temperature mangement system of the decoder, make sure the installer has not removed it or damaged it (another reason to be careful with ideas such as gluing the decoder in the shell).
The tender on the shay is a bit tricky to to remove due to the ladder on the end. It also has a couple of tabs that require some finesse to remove the shell (see your instructions or e-mail the B-mann on the Bachmann site if you have difficulty removing the shell.)
The Tsunamis tend to run hot and when they constantly show overload it is usually a defective decoder. My narrow gauge buddies have put these decoders in tighter installs than you are describing with good results, so it is not the tight fit (and lack of heat dissapation) that is causing the overload.
Guy
see stuff at: the Willoughby Line Site
If the problem is not with the current draw of the Shay's motor, you may have a defective Tsunami. I have installed the older SoundTraxx loco-specific decoders into 3 HO-scale Bachmann Spectrum 3-truck Shays and none of them exhibit the problems your Tsunami has. The Shay's motor should not be drawing more than about 250 mA unless something is binding in the mechanism.
The tender wall is plastic and will not dissipate heat. The installer may have inadvertently done something to the mechanism itself that is causing it to overload and shut down. If it was mailed to the installer, it may have been damaged in transit if it was not shipped in the original packaging material.
If it is over heating its probably due to the fact its only rated for 3/4 amp and the shay is drawing close to it or above that. You must find out how many amps the loco draws. Glueing the decoder to the tender shell will not do much unless the shell is metal and the decoder is insulated.
Pete
I pray every day I break even, Cause I can really use the money!
I started with nothing and still have most of it left!
I had a Micro Tsunami installed in the tender of a Bachmann 3 truck Shay. It runs for about 15 seconds and then stops. The installer says that it is overheating and is shutting down on thermal overload. He suggests "popping off the shell" and gluing the decoder to the tender wall.
I have never "popped the shell" off of anything. How does it come off? What are your thoughts about gluing it to the wall for thermal relief?
73
Bruce in the Peg