Electric Blanket Controller - pics

[Mr Eastwood]

A few weeks ago our electric blanket died - so I opened one of the 2 controllers and took some pics; not sure if anyone is interested;   the larger chip on the reverse of the PCB is the LM324;  the other 4 pin one has been scrubbed.   I can't understand why it died, as I checked the blanket elements and they seemed ok;  the blanket was removed from the bed just prior to both controllers failing,  each within a few days of each other - could this have been a problem with ESD on the FETs when the blanket was physically removed from the bed?

[TechJunkie]

Probably not. The FET's are most likely protected. What is it doing? No power? Any indication of power? How comfortable are you with making to voltage measurements to check a couple things.

[Mr Eastwood]

Probably not. The FET's are most likely protected. What is it doing? No power? Any indication of power? How comfortable are you with making to voltage measurements to check a couple things.

Hi,  the failure mode was;- when the unit was plugged-in and then switched to the ON position, the filament bulb failed to light; the bulb light normally illuminated the numbers on the rotary settings dial from behind; and also the LED would constantly flash at a steady interval that I've never seen before.

I've cut both cable ends off the controller but would be happy to power it up and take some measurements :-)

[TechJunkie]

Check the input mains to the fuse and a couple points after. Then check the output terminals to the blanket heater coils and let me know what they are. Also, give the status of the LED when on. Blinking, Solid, frequency of blinking, etc.

[Mr Eastwood]

Check the input mains to the fuse and a couple points after. Then check the output terminals to the blanket heater coils and let me know what they are. Also, give the status of the LED when on. Blinking, Solid, frequency of blinking, etc.

Sorry for the delay;  the input to the module is 240v a/c;  the blanket coil voltage is ~ 1.5 a/c with no load,  and 0v with load.   The element coils are ~192 ohms each.  The indication LED lights briefly at around once every ~2 secs.