Heater Blower - Fail

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sideshowbob
Posts: 247
Joined: Mon Aug 01, 2011 2:18 pm
Location: Hampshire UK

Heater Blower - Fail

Post by sideshowbob »

My heater blower now only works on the maximum setting, this is the second time this has happened !

Having used the forum to research the problem I replaced the standard transistor in the module that is situated in the fan housing. I added an extra heat sink used thermal paste and I think I up rated the transistor to the 30A, 2N3771G. I also replaced the little resistor that fits across the transistor terminals.

This is where I might have gone wrong as the new resistor I purchased although a similar colour code as the original was a lot bigger in dimension.
I am therefore wondering was this the correct resistor, and if it wasn't could it have caused the rather unexpected premature failure, although I am also doubting my soldering ability !

Any how, I intend to remove the module and replace the transistor again with either another 2N3771G or possibly a NTE 130 transistor, but my question this time is do I need to replace the wretched little resistor across the terminals. If someone who has experience on this could advise on the best transistor and the use of resistor or not I would be most grateful.

As an aside I have also inspected the blower motor bearings and oiled them and made sure that the blower cages ran smoothly in the housing as I would think that any binding here would overload the motor and hence the transistor.

Any advice would be greatly accepted.
sideshowbob
Posts: 247
Joined: Mon Aug 01, 2011 2:18 pm
Location: Hampshire UK

Re: Heater Blower - Fail

Post by sideshowbob »

Getting near to replacing transistor (again) on the little circuit board positioned ion the drivers (Euro) air intake side of fan.

Not a problem but the resistor that goes across the transistor terminals is.....firstly, is it necessary, and secondly what is its rating.

When I did this job originally I lost the resistor, bought a new one that looked like the original but much bigger, replaced transistor but it only lasted a few days and then stopped working.

Will replace transistor with the 30 amp version but the resistor rating and whether it is needed is bugging me ....HELP
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