Adding a thermal switch to subwoofer Chip Amp

[Mister Audio]

Hello there folks,
I am repairing a friends Yamaha active subwoofer. The amplifier module (CHIP) is a 60 watt Sanyo STK device.
The maximum operational thermal rating = 125 degrees Celsius.
With no cooling fins, the sub. design uses only the sheet metal of the control panel for cooling.
I am fairly sure the reason the Chip Amp/module blew-up was heavy drive at high temperature.
There is room close to the Chip Amp/module for me to add a 240V thermal switch.
My local electronics shop has a 100 deg. C thermal switch.
My question is >
Is 100 deg. too low, too high or just right for such an aplication ???

 

[Mark Tillotson]

Heatsinks shouldn't be getting hot enough to burn you, so 50C is more plausible if attached to the sheet metal, but if on the amp module itself maybe 80 to 100? And figure out if more cooling metalwork could be added?

 

[Mister Audio]

Thank you for your post.
For an extra $20 I will be recommending to my friend the addition of a 'proper finned heatsink' added to the
outside of the 'sheet metal control panel'. I think this will require stripping the black paint back to metal + transfer compound.
I also have the choice of both 70 & 90 degree thermal switches locally.
Cheers

 

[Mister Audio]

If I'm not mistaken, the STK series of power-modules don't have a very good reputation for quality (?)
Other types of Chip Amps have thermal/current limiting built into design. Some are even output short circuit protected.
Why would a company as large as Yamaha choose such a device ???
( at least there is a DC protection relay circuit incorporated )

 

[JMFahey]

You opened 2 threads on the exact same subject.

 

[Mister Audio]

Yes >
I hoped I would get more advise & opinions that way.
I hope I didn't do anything wrong

 

[Michael Bean]

Would it make more sense instead of repairing and modifying the existing amp to just replace it with something actually designed for that application?
ICEpower 100AS1 Class D Amplifier

Mike