How to debug possible fan incompatibility ?

[4erk4]

I'm seeing fans that appear to ignore (or mostly ignore) the fixed, <PWM> setting, as measured by the RPM readback, and by visual inspection.

The fan seems to move faster with a jump from 10-100 - but this is subjective.

The current configuration is just 2 fans, identical Coolermaster Sickleflow 120.

fan1,"fan1",660,22.01,100.0
fan2,"fan2",663,22.11,50.0
fan3,"fan3",0,0.00,100.0
fan4,"fan4",0,0.00,100.0
fan5,"fan5",0,0.00,100.0
fan6,"fan6",0,0.00,100.0
fan7,"fan7",0,0.00,100.0
fan8,"fan8",0,0.00,100.0

Fan1 should be at 100.0 PWM which should translate to 1800 RPM (as per spec)
Fan2 is at 50.0 PWM which should be about half that.

I am not using the mbfan at all.

Link to specification:
https://www.coolermaster.com/catalog/coolers/case-fan/sickleflow-120/#specifications

I am using the 804D kit, self-assembled, without a display
TJKO Industries,FANPICO-0804D,<OMITTED>,1.4.1

The fans section from config seems reasonable:

"fans": [{                                                                                                 [168/1502]
"id":   0,
"name": "fan1",
"min_pwm":      0,
"max_pwm":      100,
"pwm_coefficient":      1,
"source_type":  "fixed",
"source_id":    100,
"pwm_map":      [[0, 0], [100, 100]],
"rpm_factor":   2,
"filter":       {
"name": "none"
}
}, {
"id":   1,
"name": "fan2",
"min_pwm":      0,
"max_pwm":      100,
"pwm_coefficient":      1,
"source_type":  "fixed",
"source_id":    50,
"pwm_map":      [[0, 0], [100, 100]],
"rpm_factor":   2,
"filter":       {
"name": "none"
}

Any thoughts as to what I can try?

[tjko]

Those fans seems to be standard 12V PC PWM (4-pin) fans, so those should just work...

Are you able to try some other brand/model PWM fans, to see if those behave any differently?

I did quick test on the 1.4.1 firmware and I didn't see any problem setting fixed PWM output for fans, so I don't think its firmware issue.

Can you try increasing logging verbosity maybe to "INFO": sys:log INFO

Then manually switching PWM frequency and see what gets logged. When I tested it seemed to work fine (on a Noctua and Corsair fans that I had laying around).

sys:log info
[272088.948827][0] Change log level: NOTICE (5) -> INFO (6)
conf:fan2:source fixed,50
[272104.908242][0] fan2: change source fixed,100 --> fixed,50
[272105.685004][1] fan2: Set output PWM 100.0% --> 50.0%
[272106.185254][1] fan2: Input Tacho change 58.12Hz --> 56.27Hz
[272106.685201][1] mbfan2: Set output Tacho 58.12Hz --> 56.27Hz
[272107.185257][1] fan2: Input Tacho change 56.27Hz --> 41.98Hz
[272107.685197][1] mbfan2: Set output Tacho 56.27Hz --> 41.98Hz
[272108.185248][1] fan2: Input Tacho change 41.98Hz --> 32.22Hz
[272108.685219][1] mbfan2: Set output Tacho 41.98Hz --> 32.22Hz

(change on fan speed should be almost immediate and at least on my test fans there was audible change on noise level)

(If you have access to Oscilloscope it would be interesting to see what you see on the PWM pin of the FAN connector...)

[4erk4]

Wow. Thank you!

I've confirmed that JP1 is set to AUX. All jumpers are set to AUX, since I wouldn't be using the MBFAN interface.

Is there a LED or other quick way of checking the 5V rail. The Pico itself seems to draw power from USB instead of the 5v on aux, and remains powered on the 5v standby rail.

[tjko]

LED D4 should be illuminated when there is 5V power (there is test point TP3 next to it to measure the voltage as well).

You should also see "12V AUX" LED (D2) illuminated as well as "3.3V" (D5) illuminated?

[4erk4]

There is a constellation of lights, so I didn't realize there was another one there. D'oh!

LED D4 isn't lit, and the testpoint doesn't seem to have any voltage
3.3v and 12v aux are both illuminated

sensors on Linux doesn't give a 5v rail, but since USB2 works to power, I have 5v. I haven't measured at the floppy connector yet.

[tjko]

If D4 is not lit, that would point the 5V rail being down, and that would explain why fan speed control is not working (as the TTL voltage level converter chips need 5V power).

5V power rail is either powered from the MBFAN1 connector or AUX power connector, JP1 controls which is the source. So you'd want to double check that pins 1 and 2 on JP1 are connected together (with a jumper)...

Btw, you may want to double check all soldering joints for the connectors and headers/jumpers. I've myself several times missed soldering joint or two when trying to quickly assemble a FanPico...

[4erk4]

One weak solder joint. One
And on the JP1 side ..
3.3v lights up, 12v lights up.

I'm deeply sorry for causing trouble. At best, I can be an example to others of what to check for

[tjko]

Glad that you got yours working. I updated Wiki with list of LEDs and test points, and added note about making sure that "5V" LED is lit.

[tjko]

If you have an oscilloscope, you should see 25kHz PWM signal on the PWM (4th) pin on the FAN connector.

It should measure 50% duty cycle when PWM output is set to "50%" on the fanpico for that fan port:

And there should be constant ~5V signal when PWM output is set to "100%":

Also, with a digital multimeter you should see about 5V on the PWM pin when output is set to "100%" and close to 0V (in practice you probably see 0.2-0.3V) when output is set to "0%". Also some multimeters will display about 2.5V when output is set to 50%, but that depends on the meter (how its acquisition/measurement works).