My Home Depot must have less-informed help. No go.

I bought a pair of R3ZZ's from VXB via Amazon, $6 including shipping. That's got to be less expensive than the router set.
I'll report how they perform when I get around to installing them.

Dave Wise

Amazon! Of course! They have everything! I had called a local hobby shop only to be told that they didn't have R3ZZs in that size. If they work for you, I'll try a pair too.

I just visited Home Depot and checked out the Diablo router bearings. $17 for a set! Way too much for an experiment to see if they work in a Tek scope. In fact, that's almost as much as I paid for the scope!
-DS

Almost all bearings are metric, which seem odd except I believe ball bearings were first made in Europe and that set the standard.
Just about any ball bearing will do -no high heat no super high speed [e.g. 10,000 rpm]

I got the R3ZZs. They have a moderate amount of viscous friction. I am not sure the motor can spin them. The original bearings turn freely but are noisy. We'll see. At least they ought to be quiet.

Dave Wise

"... in this size of R3ZZ..."? I thought R3ZZ is the size.

If they have the rubber dust shields, you can try popping them off. Sometimes they add quite a bit of friction.

No visible rubber. I think it's the grease.

Dave Wise

R3ZZ is the NSK number for the bearing under discussion.

Cross references are:

Single shielded
NSK = R3ZZ
NTN = RA3ZZ
Fafnir = 33KDD5
SKF = WY3/16ZZ
KOYO = EE1SZZX
MRC = R3FFM
Dayton = 1ZGC1

Double shielded
NTN = RA3LL/1E
Dayton = 1ZDG1

Dimensions:
Bore = 0.1875"
O. D. = 0.500"
Depth = 0.1960"

Grainger carries both the NTN and Dayton brands. Part No. = 5U482
Daytons are about 6 bucks each.

<No affiliation>

HTH

Bill

You can get 2 r3zz bearings off of the auction site right now for $4 with free shipping.

I just did a search for r3zz, no connection with the seller, etc.

Just picked up a Tek 453 today,low serial # inthe 9000s.Same problem,nosy cooling fan.I will probably find a replacement to fit .Scope works fine only problem is dirty jumpy controls especially intensity and ch2 vert pos.Lots of brightness on CRT.I used to use one of these in the 1960s.Paid 10.00
Jim

Good job, Jim! And thanks for the tip, Paul. Just for the heck of it, I found a couple more model numbers. Some people list the depth as 10/51" (ten fifty-firsts of an inch) instead of 0.1960" or 4.978mm. What an odd size.

EBC R3-2RS
Associated ASC7935
Novak NOV5936 and 5938

The R3ZZ is still the cheapest and most abundant.

I still haven't put them in my 453, but I'm getting closer as my HP 203A Variable Phase Function Generator winds down.

Dave Wise

Maybe x/51" is an attempt to relate to 0.5mm?

Maybe; it's really close to 5mm.

Dave Wise

Update: I put in my new bearings on my early 453. It was a piece of cake. The biggest risk is breaking off the orange wire; reaching its far end would take some disassembly, but I didn't break it.

First the rear cover plate; four #2 phillips screws.
Then the fan assembly; three #2 phillips screws.
Remove the metal blade; one 3/32 hex setscrew.
Separate the bracket from the motor; three slotted screws.
Remove the motor's rear cover; one internal snap ring.
Remove the rotor and bearings; they just slide out.
Remove the old bearings with a bearing puller.
Press on the new ones by tapping on a length of tubing.
Assemble in reverse order of disassembly.
Done in 1/2 hour.

It's much quieter.

I left it running.

Overnight the HV fuse blew. More fun!

Dave Wise

That's how you find those impending problems.. fix something else!
Been there, got the rework.

Dave, you make the bearing replacement look easy. On my 453 the fan leads as very short and I can only move the fan about an inch. There is no way I can even get close to the snap ring. I'm sure the bearing part will be easy once I remove enough components to get access. Any idea how you could do this job on a 453 with short motor leads?
Keith

My fan wires were very long, and I just bulled ahead in the direction of least resistance.

But here's an idea. If your motor's like mine, the housing is bored clear through and there's a snap ring on each end. Instead of accessing the rear like I did, remove the front ring, and pull the rotor out by the shaft. Unfortunately, the bracket is too small to pull the rotor through, so you will still have to remove it and take it off the motor. There is also a chance that the rear bearing won't come out. If you're lucky and it does, do this with the scope on its face so the rear wave washer stays centered, otherwise you'll have to tack it in place for reassembly.

If that fails, just cut the wires, leaving enough pigtail off the motor to splice in some extra later.

For what it's worth, I know where three of the four wires connect, if your 453 is built like my early one. Green and black (shown as one wire on the schematic) go to the far end of the 0.5uF bathtub cap, and blue and a non-motor wire go to the near end. Orange goes to the line voltage switch but I couldn't see just where. The schematic shows it in the junction between (a) one of the high-low common contacts , (b) a 115-230 NC contact, and (c) a 115-230 NO contact. It's possible to distinguish this node from the other high-low common; the latter goes to a 115-230 common. Just start tracing at the high-low commons, and use the one that goes to two terminals (not one) on the 115-230 switch. It should be possible to figure this out with an ohmmeter. If the orange wire does break, just snake it out to the high-low switch and solder it there. The other wires can be soldered through the mounting hole.

Dave Wise

After confirming that the HV supply had no shorts, I popped in a new fuse and it went on its merry way. I Will Be Watching...

Dave Wise

Vintage Dave: I'm wondering where you find a bearing puller for these small bearings. Maybe an RC hobby shop? (Edit: I managed to remove them with an old, cheap bearing puller that had been rusting in the bottom of my toolbox for decades.) Also, what is the proper order for the three or four types of shims that are inside the snap ring: four thin shims, one thick shim, one springy shim. The first time I took this motor apart the shims popped out and flew all over the place. I lost track of their proper order.
-DS

Sorry, DS. My bearing puller came from a garage sale, and my motor doesn't have any shims except for the compression (wave) washer against the rear bearing. That is, if it has shims in front, I don't know it, because I never looked, nor turned the housing wrong-way-down and dumped them.

I would think that if it has shims, their purpose is to center the armature within the stator, for maximum torque. If you have a depth gauge and a flashlight, you can probably measure the position of the pole pieces, compare to the rotor, and calculate a shim stack that will center it.

Dave Wise

Well, since my fan leads are so short I decided to take vintage Dave's idea to try to remove the armature by removing the front C-clip and pulling the shaft out from the front. Cutting the wires was't even an option since I can't even pull the motor out enough to cut them. The shaft came right out but the rear bearing stayed in place. The front bearing was shot and had so much play that the fan was hitting the shroud. I suspect that the front bearing took most of the wear so I'll replace the front with a new bearing and I'll oil the rear bearing with synthetic oil using a long needle on a syringe. At least the fan won't be hitting the shroud anymore and with oil on the rear bearing I suspect this thing will be silent.
I'm ordering a bearing tonight and I'll post again if I'm successful.
Thanks for all the help.
Keith