Servicing the fan motor on the 535A. For the first 5 minutes after power up it would rattle and run at half speed. Once heated up would spool up to normal speed with no more rattle. So the sleeve bearings must be dry.
The fan is held on the motor shaft with a allen key which came out fine but the fan is pretty much seized to the motor shaft. I didn't want to pry too hard so I left it. In addition the motor is hard wired in so had to let it hang out as shown.
I found a date! June 3, 1966. That explains a number of things with this 535A. First, the BNC's rather than UHF connectors. Tek converted to BNC in 1963. Second, early 535A's had wax caps and “bumble bee” caps both of which went leaky. This one has epoxy caps which last forever. So this is a late version of the 535A. It went out of production in 1972.
I was able to get the backside of the motor apart and clean it up and re-oil the sleeve. I have a long pin point oiler so I was able to get to the front sleeve although couldn't clean it. Reassembly and the fan comes up to speed immediately with no rattle. Should be good for a long time.
Tomorrow continue with the filter cap change.