XR15 Fan always full power

[Slig1980]

Hi all. I recently replace an led of my XR15 G3 Pro and the LED's are now working again but the fan is now always at full power and very loud.

I have checked the RT1 Thermistor and it reads around 11k with the power off, however when I turn the light on I get OL which could explain why the fan circuit thinks it is too hot and needs to be on full speed but don't know what could be causing this behavior.

Any thoughts would be very helpful as not sure what else to check.

 

[oreo54]

Hi all. I recently replace an led of my XR15 G3 Pro and the LED's are now working again but the fan is now always at full power and very loud.

I have checked the RT1 Thermistor and it reads around 11k with the power off, however when I turn the light on I get OL which could explain why the fan circuit thinks it is too hot and needs to be on full speed but don't know what could be causing this behavior.

Any thoughts would be very helpful as not sure what else to check.

Possible help? It gets into the thermistor circuit.
https://www.reef2reef.com/threads/debugging-a-busted-radion-xr30w.708739/

 

[Slig1980]

Possible help? It gets into the thermistor circuit.
https://www.reef2reef.com/threads/debugging-a-busted-radion-xr30w.708739/

Thanks, that's the thread that brought me to the forum, unfortunately they never got to the specific fault. I have been over as many of the components trying to trace the circuit but struggling now to the bottom of it.

 

[_AV]

Assuming the fan worked properly prior to the repair, I'd start by taking a real close look at the cluster and make sure no traces got damaged or pins lifted.

 

[Slig1980]

Assuming the fan worked properly prior to the repair, I'd start by taking a real close look at the cluster and make sure no traces got damaged or pins lifted.

The fan wasn't working prior, think that's what caused the led's to overheat and stop working originally. I tried to get the fan working again once the led's were fixed, took off a couple resistors to measure on the fan control line from the MCU and they read fine out of circuit. Put them back on and the fan started working again, just at full speed. I have traced all led's and components on the cluster back to the pins and they all show continuity to the connecting pins. Just seemed odd that the thermistor changes value and goes open as soon as the lights are powered on.

I will open it back up tonight and recheck to be safe.

Thanks

 

[_AV]

The fan wasn't working prior, think that's what caused the led's to overheat and stop working originally. I tried to get the fan working again once the led's were fixed, took off a couple resistors to measure on the fan control line from the MCU and they read fine out of circuit. Put them back on and the fan started working again, just at full speed. I have traced all led's and components on the cluster back to the pins and they all show continuity to the connecting pins. Just seemed odd that the thermistor changes value and goes open as soon as the lights are powered on.

I will open it back up tonight and recheck to be safe.

Thanks

Did you find that the original fan failed shorted?
Also, I wouldn't trust resistance readings on the live circuit. Voltages - yes, but not resistance/capacitance.

 

[Slig1980]

Did you find that the original fan failed shorted?
Also, I wouldn't trust resistance readings on the live circuit. Voltages - yes, but not resistance/capacitance.

no the original fan is the one working now, tried other fans too but same fault. I agree with you on the readings that's why I removed the 2 resistors to check out of circuit as the readings on the boards didn't seem right but once removed they tested fine to put them back on and the fan just started working again

 

[_AV]

no the original fan is the one working now, tried other fans too but same fault. I agree with you on the readings that's why I removed the 2 resistors to check out of circuit as the readings on the boards didn't seem right but once removed they tested fine to put them back on and the fan just started working again

Yeah.. My bet is that either the traces got damaged or pins got lifted on the cluster when you put the components back on. This effectively disconnected the speed control part of the circuit, which previously won't let the fan turn on, and now the fan is running full speed unchecked.

 

[Slig1980]

Yeah.. My bet is that either the traces got damaged or pins got lifted on the cluster when you put the components back on. This effectively disconnected the speed control part of the circuit, which previously won't let the fan turn on, and now the fan is running full speed unchecked.

Just checked again and all the led's light up so they are connected ok. Traced back between all other components on the cluster and they all connect to each other and back to the pins (going to the motherboard). Only changed an LED on the cluster.

The 2 resistors I took off to check and added back on were the 2 in the attached picture on the main circuit board. one looks white just cause it went back on upside down but that shouldn't matter. There is also continuity between those resistors and connecting components as well as back to the MCU