Avalon 741 fan always running at max

[Geronimoe]

Hiya hoping this is just a setting issue.
Just bought some used Avalon 741 units from cryptouniverse.

And when I say used I should say abused.
Two of them have big dents and casing not fitting correctly anymore and one of them hashes ok but fan is running at max even when temps are low and even when not hashing.
They where all full of dust and insects and smell like they where run in a chip shop.
Anyhow i have swapped fan from a known good unit so looking for suggestions what to do next.

cheers Geronimoe

[1715201667]

1715201667

[1715201667]

1715201667

[1715201667]

1715201667

[ecosprog]

Hi Geronimoe,

I have some of these used miners from CryptoUniverse as well, but mine were clean with just a few scratches on the cases.

I had a similar problem to you with one of my miners. The fan always ran at 5200 rpm no matter what the chip temperature. The good news was that it hashed at 8GH/s. I solved the fan issue by going in to the CGMiner configuration and setting the voltage offset to -1. The fan now behaves normally, and the hash rate is at 7.6GH/s.

Hope this helps.

[Geronimoe]

Cheers for the reply.
Found the problem was the small PCB between the fan connector and fan lead had a damaged track which was the yellow wire for controlling fan speed.
Repaired track and now working as should.
I think the problem with the condition of mine is if your a Business to Business customer there was no warranty offered on these.
Ergo the worst condition get sent to business custards.
2 of the units have about 10% device hardware errors and i am in the process of stripping, cleaning and re-thermal pasting them so fingers crossed.