My current fan controller has 3 configurable dials

1. Temperature
2. Maximum Speed
3. Minimum Speed

The problem is, the Maximum dials range is between 50% and 100%... I need it to start lower.

See "Max. Fan Speed" Dial




The moment the room temperature goes above the temperature set by the dial, the fan immediately jumps to 50% speed or higher, but I would like the fan to first start at around 25%, then 30, 35%, etc...

Here's a picture of the underlying PCB, is there a way I can modify or swap over some of the components?

One idea I had was to buy another identical unit, unsolder the bottom dial(minimum temp) from the new unit and swap it with the middle dial(max temp) on my current unit, ideally hoping to get a range of 20-100%... but this may not work as it could be the other components which control the range...


I would be willing to pay - upfront - for some help to resolve this issue as quick as possible.

Regards

 

All your issues are probably coming from the likelihood that it is a "Triac-type" Dimmer-Circuit.

And, many Fans will not "Start" at less than ~50% Power,
especially if the Oil in the Bearings is starting to get a little old and "gummy",
that's why it was designed that way.
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.
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All your issues are probably coming from the likelihood that it is a "Triac-type" Dimmer-Circuit.

And, many Fans will not "Start" at less than ~50% Power,
especially if the Oil in the Bearings is starting to get a little old and "gummy",
that's why it was designed that way.

LowQCab, Thats not true, The fans will run at 1% onwards. They are new EC PWM controlled fans
If you take a look at the first picture, it shows the minimum speed starts at 20%.

This is futher validated by using the controller it came with(that doesnt have temperature settings). the speed adjustability is huge.

Im willing to pay upfront if somebody can provide a workaround

 

The PIC16 controller on that board actually sets the speeds and temperatures. The initial speed is set in the controller firmware, you would need to change that. No idea if there are user modifiable defaults but there might be a procedure in the user manual to change defaults by some sort of 'secret' sequence at boot.

 

What is the min setting for if it always goes to the max setting?

 

No schematic and no source code. Your chances of success appear to be vanishingly small. Developing your own custom version from scratch might be quicker and cost less.

 

What is the min setting for if it always goes to the max setting?

The min setting is what it runs at before triggered by exceeding set temperature.
Then it goes straight to 50%, IE overkill.

 

The PIC16 controller on that board actually sets the speeds and temperatures. The initial speed is set in the controller firmware, you would need to change that. No idea if there are user modifiable defaults but there might be a procedure in the user manual to change defaults by some sort of 'secret' sequence at boot.

Thanks, how would you advise connecting to it to see if I can modify any defaults?

Checking this video now which seems useful

No manual comes with this controller, its too commercial/for profit for that sort of thing

 

Thanks, how would you advise connecting to it to see if I can modify any defaults?

Checking this video now which seems useful

No manual comes with this controller, its too commercial/for profit for that sort of thing.

If, you're, very lucky, there is an ICSP header on the board that might be able to read the firmware if it's not (but very likely is) code and data protected.
http://ww1.microchip.com/downloads/en/devicedoc/40001839b.pdf
If, by some miracle, you can download the intact firmware binary then someone would need to disassemble the code into something understandable to alter the contents, make changes, create a new binary and reload the chip with the new firmware.

It's not like the movies, this takes real skill, time and luck with luck being a big factor in success.

There is also what looks like at TTL serial header that might provide some sort of info

 

It sounds like it maybe easier to build a complete pwm controller start to finish...