I can advise you use NE555 schematic for cheating the Z1 Pro firmware. I use it and use big and quiet canal fan for cooling. Schematic very simple like this - https://forum.bits.media/index.php?/topic/86018-antminer-z9-mini/&do=findComment&comment=1603612 and canal fan Binetti FDS-150 - https://bt.rozetka.com.ua/benetti_fds_150/p32889159/?gclid=EAIaIQobChMInMamm4r35QIViOAYCh2tBgJeEAQYASABEgKhU_D_BwE . Also i use another one little schematic to control FDS-150 speed like this - https://ru.aliexpress.com/item/4000141348880.html?spm=a2g0o.productlist.0.0.695a2d24nTBdO9&algo_pvid=b93d3086-5645-469d-9f26-d632b7219b18&algo_expid=b93d3086-5645-469d-9f26-d632b7219b18-54&btsid=979f8bbd-1b54-4b3c-9d14-b19c1125fe74&ws_ab_test=searchweb0_0,searchweb201602_7,searchweb201603_52 and already ordered Wi-Fi dimmer for that fan. When i get it i will control fan speed remotely - https://ru.aliexpress.com/item/4000060437817.html?spm=a2g0s.9042311.0.0.5afb33ed6unt1Q . As for me i use speed lower then a half.