I think your problem is related to loose heatsink and I think you will need to find that chip to reattached the heatsink.
But if you don't have some tools to reattached those heatsink this guide below to refresh your miner and hashboard and it might also solve your overheating issue on some chips.
can you send the command for autotuning of chips, my one chip is exceeding 120c mark and voltage is around 338, although miner is working good at 82th stable.
can you share the command line please,
thanks , looking forward for your reply
Try to refresh the miner's ASIC chips through the FMS tool you can download it from this link below
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https://canaan.io/wp-content/uploads/2020/03/FMS_V2.3.3_Windows.zipAnd then look for the aging tab and select any hashboard with high ASIC chip temp.
If it still overheating manually set the fan speed to 100% to test if it can help to cool down those chips
To set the fan speed you must have the FMS tool and then go to diagnostic and put this command below
[b][{"command":"ascset","parameter":"0,fan-spd,90"}] [/b]
Fan-spd,90 it's a fan speed with 90% you can replace it with 80% or 100% to try if it fixes the issue.