Can an A&H official explain how the CQ12T is supposed to behave ?
At startup, core temp is around 72 C and the fan is around 1000 rpm.
Core temps quickly raise to 77 C and Fan goes above 2300 rpm.
I never noticed that behaviour before, because my fan rpm was always around 1000 rpm whatever the core temp.
I noticed it because of the fan noise at 2300 + rpm witch is quite annoying now.
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I think it is safe to say that the fan has a controller on it that speeds the fan up as the internal temps rise.
There are several reasons why this might be happening now when it hasn’t in the past. First, if it’s summer where you are, the operating conditions might be hotter. Second, the air vents might have gotten fouled with dust or other material that is restricting the normal air flow. You might need to clean the vents/housing to restore good air flow. Third, it’s possible that A&H adjusted the fan controller settings during a firmware update because they realized the internal temps were getting too hot.
It’s also possible that the fan’s bearing is simply louder than it was originally. Therefore the fan might be spinning at the exact same rate as aways, but it’s louder than it was originally. This could be lead you to believe something has changed with the fan controller when it fact it might be a worn bearing.
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Thank you for the prompt reply.
I might have found the reason of this issue and I share with you my stupid mistake.
Last week I removed the backplate of my CQ and the fan to carefully clean the inside after a week of usage in a very dusty and hot environment.
By mistake I mounted back the fan upside down.
It was not blowing fresh air inside anymore but trying to extract hot air from the inside.
This was not as efficient as originally designed I guess.
All is OK now (running a test while I am writing this reply), fan idling at around 1000 rpm, core temp steady at 76 C.
Apart from that, all you mentioned above is fully true and it might be that one day the fan goes down.
Should this happen, I think that swapping with a new spare fan is an easy operation (if your mixer is out of warranty of course) and because I opened my CQ up, I can share with you the characteristics of the fan.
It is a PWM (4 wire) 12V size 60x60x15.
There are lots of silent fans (Noctua) that would match.
Thank you sic0048.
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