25 Sep
2015
25 Sep
'15
7:18 p.m.
On 09/25/2015 03:45 PM, devin davison wrote:
I have a BA11K power supply out of a pdp 11/34 that
has frozen up fans.
They are frozen up pretty bad. I heard from another list member here they
are repairable, any advice on how to do so?
--Devin
Generally, you can remove a snap ring and pull out several
components from the hub of the fan. Then, there is a TINY
phosphor-bronze snap-ring on a post in the center. When you
remove it, be careful to shield the fan with your hand to
catch the ring if it flies off. Then, the fan can be
removed from the motor stator. If ball bearings, you can
measure and buy replacements from Boca Bearings (or other
source). if sleeve bearings, you may have to drip solvent
into the bearing area first to loosen it up, then it will be
possible to remove the fan, and clean the bearing and post.
Then, oil liberally with 10W oil and reassemble. Be sure to
oil the felts as well. For sleeve bearings, this is usually
a stop-gap, but will work for seldom-used gear. The Boca
Bearings bearings usually get noisy sooner than the OEM
bearings, but they will still last several years of running
time.
Different brands have slightly different construction, but
many of them follow the above general design.
Jon