SVT-3 PRO fan problem

[ghurm]

Just picked up a SVT-3 PRO sounds great with one caveat: as soon as it
is powered up the fan runs full blast. This never stops as long as the power
is on. Running idle and cool, fan still going full strength.
Could this be a bad sensor? Amy ideas?

Thanks for any help
ghurm

[tim]

If I remember correctly, there is a transistor switch in the fan enable circuit...I don't have a schematic in front of me to know for sure...someone with a schematic will surely chime in eventually...

[ghurm]

More Fan Info

After further investigation seems a previous owner blew the bearings on the fan ('98 era), so may not be speed as much as very noisy fan. Need to replace fan "Comair Rotron Sprint DC ST24A3". Does anyone know if they upgraded this model since '98 or if there is a quieter substitution?

[warnergt]

Looking at the Comair Rotron website, it appears that there is a fan equivalent
to the Sprint DC ST24A3 but with ball bearings. That fan would be the Sprint DC ST24B3.

And it appears that Digikey sells the Sprint DC ST24B3 for $39.58.