It is to my understanding that this board is a bit dated however I would like to know if any techie would have any insight to a problem that occurred under no fault of the board. I set up all new components however the only thing that matters is the case intake fan which was under 125mA, this and the AMD brisbane fan was controlled by the PWM fan control 'smart fan'. Well upon booting the system it didn't boot, hard rebooted pressed/held insert key and re-started, it booted and went to Bios blah blah blah....
Anyway get the mother setup and running, then I decided it is time to put the new intake fan on to see if the fan throttling deal works it did and a few days latter the HA8550 Planar transistor went poof ahh the smeal. Tested every fan I got in there and it turn out that the fan I just got shorted power from this tranny to ground, openned the fan and a stupid solder ball was crossing a gap from a joint towards the center to ground dead short however the fan works after rework.
I am wondering if this PNP epitaxial planar trans has any current protection against the base in this case, the datasheet says 100uA under test conditions. I already found a suitible replacement STX790a. Basically the collector drove a load of zero ohms to ground and the SYSfan PWM driver transistor went nukular.
I have not pulled the mobo out to view underneath I doubt this circuit is in the 2 or 3rd layer as it is higher current, the only thing I see that would be in the layers is the pwm signal. The processor fan is locked in at 65 and can be changed manually but won't throttle untiI re-flash I already know that the PWM module has a lockout under a fail contition in bios.
This weekend I and pulling the bruised part and re-flashing the bios and hope the pwm circuit throttles the cpu fan.
Anyway get the mother setup and running, then I decided it is time to put the new intake fan on to see if the fan throttling deal works it did and a few days latter the HA8550 Planar transistor went poof ahh the smeal. Tested every fan I got in there and it turn out that the fan I just got shorted power from this tranny to ground, openned the fan and a stupid solder ball was crossing a gap from a joint towards the center to ground dead short however the fan works after rework.
I am wondering if this PNP epitaxial planar trans has any current protection against the base in this case, the datasheet says 100uA under test conditions. I already found a suitible replacement STX790a. Basically the collector drove a load of zero ohms to ground and the SYSfan PWM driver transistor went nukular.
I have not pulled the mobo out to view underneath I doubt this circuit is in the 2 or 3rd layer as it is higher current, the only thing I see that would be in the layers is the pwm signal. The processor fan is locked in at 65 and can be changed manually but won't throttle untiI re-flash I already know that the PWM module has a lockout under a fail contition in bios.
This weekend I and pulling the bruised part and re-flashing the bios and hope the pwm circuit throttles the cpu fan.
Facebook
Twitter
Instagram