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Rega RB300 Tonearm Problem

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Rega RB300 Tonearm Problem

Postby dilburt » 01 Jun 2012 18:24

I have a Rega Planar 3 turntable with a RB300 tonearm and Elys cartridge I purchased almost 30 years ago which has been trouble-free until recently. A while ago I noticed that the tonearm was loose so that it would move slightly when lowering the tonearm with the lever. At first this movement was very slight but it's increased over the past year to the point where it can cause the stylus to miss the intended landing point if I'm not very careful. My first thought was the large nut at the bottom of the turntable but I verified that this was tight. I eventually removed the tonearm and found that the problem exists between the base and the anti-skate body. The movement is perhaps 1-2 mm in each direction at the base but of course the distance is much greater at the stylus. According to diagrams I've seen, it appears there are 2 screws that fasten the anti-skate body to the base but these are hidden under covers. I have carefully tried to pry up the covers using very sharp tweezers but they don't budge and I don't want to tear up the covers or the anti-skate body.

I have a few questions I'm hoping someone can answer for me:

1. Is it likely that these screws are responsible for the movement between the anti-skate body and the base?

2. If so, what is the trick for removing the screw access covers?

3. Are there any potential problems I should be aware of when tightening these screws? For example, should I attempt to do this while the tonearm is attached to the turntable or should I remove it first?

D
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Re: Rega RB300 Tonearm Problem

Postby dilburt » 01 Jun 2012 22:43

Well, I solved this myself once I realized that one of my project objectives was simply not possible. You cannot remove the screw caps without doing some damage to them. However, I was able to minimize damage by using very sharp tweezers (needle-sharp) to dig into the edge of the cap enough to pop it off.

Once the two caps were removed I found that they covered small Allan-head screws. I don't have any calipers but I think the allan-wrench size that fit was 1/16" although it may have been an equivalent metric size. These had become remarkably loose and required 1-2 complete turns to fully tighten. It's possible to do this with the tonearm mounted to the turntable and you can almost reach the screws with the tonearm locked in place. However I found I had to move it a little to get the best access for each screw so make sure the raising mechanism is up to protect the stylus. Now that the screws have been tightened the tonearm is as solid as new.

Hopefully someone else can benefit from this info at a later date.

D
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Re: Rega RB300 Tonearm Problem

Postby ambrosia » 20 Nov 2013 03:57

i have a rega 300b tonearm , is there anyway of repairing or replaceing the bearing in the tonearm base housing ? for some reason the arm does not move smoothley and freely acroos the record ,it skips because apparantly friction is to high for the tone arm to follow the grooves . what could have caused this ? can anybody help ?
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Re: Rega RB300 Tonearm Problem

Postby JaS » 20 Nov 2013 09:47

ambrosia wrote:is there anyway of repairing or replaceing the bearing in the tonearm base housing

In theory, yes. I've never done this though and apparently it's quite easy to break the vertical shaft undoing the securing nut. I'd check it definitely is a friction issue first, then look for other causes like the tube hitting the lift platform, or badly routed internal wiring :-k

http://www.audiomods.co.uk/regafacts.html

Regards,
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Re: Rega RB300 Tonearm Problem

Postby zharca » 20 Nov 2013 15:03

The most common cause of the arm not swinging freely is a DIY rewire, and it's much more likely to be wiring than bearings, which are very reliable unless the arm has been dropped.

A repair on the horizontal bearings is not a diy job. Most common issues are breaking the plastic anti-skate mount, damaging the shaft or unscrewing the arm yoke instead of the shaft nut. Even if you get it apart, new bearings don't just press back. Without the right tool (which has a precision-ground 6mm shaft and threaded mandrel to align them properly) you are very unlikely to restore them to factory standard.

For a proper rebuild try Johnnie Nilsen at Audio Origami, who's done hundred of them.
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Re: Rega RB300 Tonearm Problem

Postby ambrosia » 20 Nov 2013 18:06

thanks guys for responding , i think i just found the solution ! first you must remove the tonearm from its mount and remove the wiring , i unscrewd the bolt that is inside the tonearm mounting shaft where the tonearm wiring comes out , then i used a 6 inch long 1/2 inch diameter piece of round wood that i had for makeing dowels , i inserted the round wood piece so it sat on the bearing shaft inside the bottom of the tonearm mountig shaft and with a rubber hammer tapped the end of the wood sitting on the bearing shaft and the tonearm mount lifted , and low and behold underneath was some gunk causing the friction , it was lodged on the sides of the inside botom of the lift where there are magnets attached on each side , i cleaned it and then gently pushed back in the mount so that it sat in its original position , i reinserted the small bolt on the inside of the mount makeing sure that i did not over tighten .
now the arm swings freely and tracks and follows the groove effortlesly .
the gunk got in there because i previouly tried to rewire the arm and when pulling the wires through they stripped and some of the lining got trapped underneath the inside the bearing housing causing the problem .
i am posting this in case someone else may encounter the same problem .
p.s it is not necessay to pull the arm mount all the way out ! you need just about a half inch of clearance so you can flush out the debris . pulling the lift all the way out is very risky ! you may not be able to reinsert it back in .
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Re: Rega RB300 Tonearm Problem

Postby awty » 20 Nov 2013 20:28



Wish I saw this before I replaced the bearings in my rb300, then I would of known about the screws in the vertical shaft #-o .
Still not a hard job, not sure what all the fuss is about, certainly a lot easier than doing the bearings on a ortofon as212.
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Re: Rega RB300 Tonearm Problem

Postby ambrosia » 22 Nov 2013 06:27

i just finished installing my rega 300b tonearm on a garrard 301 , after several tests all seemed well , but when i finally installed it and secured everything in place , re installed a stanton cartridge , set tracking force and antiskating , went to play some vinyl and a big problem pops up , the arm will not follow the grooves , the antiskaing keeps pulling the arm to the right ! whats going on ! has anybody got a solution ! i have installed cartridges , set tracking force and anti skating many times on other systems with no problems , this is the first time i came across this , i increased the tracking force for experimental tryouts and it seemed a litle better but when it reaches the last tracks of an lp it will not go into the end of play grooves , it keeps jumping back into the last tracks .
the arm glides smoothely across the lp with no apparant friction but when in the grooves it keeps pulling to the right or the outside of the record . even when i set the antiskating to zero .
any advise would be greatly appreciated .
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Re: Rega RB300 Tonearm Problem

Postby zharca » 22 Nov 2013 07:17

ambrosia wrote:i just finished installing my rega 300b tonearm on a garrard 301 , after several tests all seemed well , but when i finally installed it and secured everything in place , re installed a stanton cartridge , set tracking force and antiskating , went to play some vinyl and a big problem pops up , the arm will not follow the grooves , the antiskaing keeps pulling the arm to the right ! whats going on ! has anybody got a solution ! i have installed cartridges , set tracking force and anti skating many times on other systems with no problems , this is the first time i came across this , i increased the tracking force for experimental tryouts and it seemed a litle better but when it reaches the last tracks of an lp it will not go into the end of play grooves , it keeps jumping back into the last tracks .
the arm glides smoothely across the lp with no apparant friction but when in the grooves it keeps pulling to the right or the outside of the record . even when i set the antiskating to zero .
any advise would be greatly appreciated .


The anti skate generally still exerts some force when it's set at "zero" but not enough to cause problems. This sounds like twisted wiring in the base is the most likely cause. Has it been rewired or has the base plug ever been removed?
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Re: Rega RB300 Tonearm Problem

Postby ambrosia » 22 Nov 2013 18:10

hi! yes i rewired the tonearm and also the base plug was removed in order to lift the arm support so as to remove debris from the base of the tonearm that was preventing the arm from swinging freely and smoothely , i solved that problem only to encounter this one .
the arm keeps pulling to the right when trying to play a record , otherwise it feels very smooth and moves freely and effortlessly from left to right , just when i try to play a record this happens no matter what position i set the antiskating .
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Re: Rega RB300 Tonearm Problem

Postby awty » 22 Nov 2013 22:57

The anti skate works by using magnets, the closer you push the magnet to the arm base the more anti skate you get. Set at zero the magnets are too far apart to cause much anti skate.

As said before its most likely the wires. I had a similar problem when replacing the original wires with a kit I bought from ebay. The wires were single strand silver plated and it didnt matter what I did I couldnt get it right, especially bad with a light tracking force, the wires were too stiff. Replaced the wires again with Litz 33 AWG multi strand copper and it worked fine.
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Re: Rega RB300 Tonearm Problem

Postby zharca » 23 Nov 2013 01:12

Yes, sounds like a typical diy rewiring issue.

The type of wire used and the dressing of them within the base are important. Also whether the original rubber plug within the bearing shaft has been retained or removed and how the ground wire has been refitted.

The 300 is less forgiving of a rewire than the 250 series because the bearing carrier allows less flexing of the cable. You need a wire no stiffer than the original Rega one and dress it carefully so that it can flex over the whole length of the bearing shaft without catching or rubbing on the shaft.

When using replacement wire it's best to install the loom from the base as having enough spare wire in the base to be able to remove the plug won't work with anything but the original.

You might get an improvement by rotating the plug anti-clockwise, worth a try or it could make it worse!
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