Trio Kenwood KD-1033 turntable main bearing service

 

One of my first posts in this blog was regarding the servicing of the Pioneer PL12D turntable, and that has proven to be the most popular by a significant margin. The Pioneer PL12D had its competitors, and probably the most popular alternative was the Trio Kenwood KD-1033 turntable. I use both names (Trio and Kenwood) as the company operated under different names in different markets. In the UK they were Trio, possibly because the brand Kenwood was most famous here for food blenders.

95% of a KD-1033 is similar to  Pioneer PL12D, and servicing them is very much the same process. Both are belt drive , have an AC synchronous motor,  mechanical speed change , a main bearing, sprung top deck and rubber motor mounts. the KD-1033 uses a different type of anti skate mechanism, employing a thread and weight. The plinth is shallower with an internal cross brace.

One aspect that is different is the design of the main bearing, and servicing it is a little harder than a PL12D. The Pioneer main bearing is a Brass well into which a ball bearing sits, with the spindle on top. the spindle is held captive by a side screw. Its very easy to dismantle and service.


The KD-1033 uses a brass well, but has a hole at the bottom, making it an open bearing. Inside it has both a metal disk to cap off the hole at the bottom, and had a plastic thrust pad, on which the ball bearing sat. The ball bearing is held captive by a conical recess in the base of the spindle.
The spindle is held captive not by a side screw but by a side rivet. I have seen posts on forums where this is referred to as a blob of solder, but it is a rivet.

If you are restoring a KD-1033 it's worth properly servicing the bearing, as the original may exhibit a number of problems, including the original grease drying out, and the thrust pad crumbing with age. These issues can cause the platter to rotate at the wrong speed , and sit too low . 

The whole assembly is threaded at the collar and uses a brass nut and washer to attach to the turntable top plate. Servicing is much easier if you undo the nut and remove the whole thing, taking care to keep the nut and washer safe. Here you can see the whole assembly. I have replaced the retaining nut and washer to keep it all together. You can also see the side rivet, here after loosening 

The service guide for this deck doesn't cover this process. The whole bearing assembly has one single part number and exactly what is inside is not explained in any exploded views

Service guide exploded view

I have read of people using either pliers to extract the rivet or drilling it out. I found I could fairly easily tease it out with a sharp knife. Its held in by a snug fit and some threadlocker adhesive, the latter can be scraped away first with the knife. With the blade I teased the edge of the dome and was slowly able to lever the rivet out

With the rivet extracted, you can disassemble the bearing assembly into its constituent parts . You can see the metal disk , which sits at the bottom of the bearing well to cap it off. The ball bearing is still inserted in the base of the spindle in the picture, being held in by gravity and any residual grease and will come away with cleaning. The ball bearing appears to be 4mm diameter. NOTE I found no plastic thrust pad, though the metal disk and spindle had blobs of an unidentified green substance. This might be old grease, but I suspect the original pad has completely disintegrated and mixed with the grease.

I thoroughly cleaned the parts to remove the old grease from spindle and brass bearing sleeve.

I ordered some PTFE sheet of 1mm thickness. Possibly the deck originally used Delrin for this pad, but PTFE is even better and cheap to buy from ebay. After one attempt with a  knife, I found the easiest way to make a pad was to punch them out using a desktop hole punch. They are slightly smaller than the hole but were good enough and it's an  easier and neater solution.

Assembly involved a blob of silicon grease to adhere the ball to the end of the spindle and the pad to the ball. I purchased a pack of new 4mm bearings as they are cheap and the old one was pitted. I also put a smear of grease around the bass of the bearing well to make an oil-tight seal with the disk.

NOTE The disk had a dimple which was the contact point with the ball bearing. I assume this was from wear with the ball, and I kept this surface facing upward, with the PTFE pad now seperating ball from disk. I put a few drops of oil along the sides of the spindle shaft, thus using a mix of grease and oil as lubricant , as per best practice with the Lenco GL75 open bearing of similar design.

Finally I reinserted the rivet and resealed with a drop of loctite Thread Bond

The bearing felt noticeably smoother to turn and I await feedback from the owner to see if it has addressed speed and fouling issues he was experiencing. if successful I plan to offer this as a service for people who want to restore KD-1033 turntables and might like to have someone service the bearing for them, it's cheap and easy to do by return of post.