Blower motor Transistor substitution/check

[ashfixit]

A question for the analog design enabled among us.. The blower motor transistor from my 94' is a Toshiba 2SD1460 which may or may not be well on my car - but has failed for numerous nsx lovers; and has left production for good reason.

The toshiba part is a darlington NPN for Hfe > 1000, @ Ice = 20A Vce = 5v; and it's got some pretty hard looking extremes.
http://www.datasheet-pdf.com/datasheet-html/2/S/D/2SD1460_Toshiba.pdf.html

Does anyone know how to characterize a failed part with a meter ( Diode check on b-e? ) or does it require a rig to exercise it's Hfe?

If this brave NPN has gone to join chip-valhalla - have we identified a substitution part? Quick parameterization with mouser suggests the NPN side of this couple for a big $5::triumphant:

http://www.onsemi.com/pub_link/Collateral/MJ11012-D.PDF

I may try this and get back to you before you can warn me about choosing a device based on Hfe and a dartboard.

 

[Old Guy]

The go-to replacement seems to be MJ 11016 which is available at Digikey and a number of other vendors. Toshiba 2SD 1460 has a collector current rating of 30 A and a Vce of 100V. MJ 11016 has a collector current rating of 30 A and a Vce of 120 V. I didn't confirm the specs on the Darlington pair you identified; however, a Vce of 5 V definitely won't cut it. The continuous current rating is also marginal. Switching transistors tend to run off or in saturated mode, so the Hfe value isn't a huge factor.

If the blower motor runs with the fan speed setting on high, that pretty much confirms that the transistor is toast. On the highest fan speed setting, there is an external relay which shorts across the collector and emitter of the transistor to apply 12 v continuously to the fan motor.

 

[nikey22]

so far, mine is working okay - I cleaned the heat sink (its huge).

 

[Briank]

The stock transistor is very robust and I have never seen a failed one. Inside the assy their is a thermo fuse that goes out that can be replaced but with the potting its not worth the effort. Installing a new power transistor assy is the fix if its truly bad. About 95% of the blower issues are caused by the control unit. The problem that causes the thermo fuse to fail is a bad blower motor (drawing too much current) so if you have a bad power transistor assy the blower motor needs to be replaced at the same time.