google-site-verification=ximqu9i2LRKyaJhJg33bbbHmBdOczA19Kmogx3rAi7A Garrard 301 refurbishment, Bath, U.K.

Garrard 301 Refurbishment

The Garrard 301 and 401 turntables are both classic designs which at some point in their life will need some sort of maintenance or repair. They have a fan base throughout the world and are a tribute to the company who made them.  

 

Following a request by a customer to refurbish an early grease bearing 301 turntable I thought it would be of benefit to record the basics of the work here.  I was very impressed to receive through the post a box lined with 5mm plywood within which was the turntable mounted on a temporary plinth. For anybody contemplating sending a turntable through the post this is a very easy way of ensuring safe transit.

 

The following information is taken in part from the rebuild of this grease bearing model and also from a later oil bearing model finished in a retro blue powdercoat.

The turntable as it was delivered in it's plywood cacoon

Warning

The links and associated metal parts are plated with Cadmium which is a heavy metal. Cadmium is dangerous and can cause local skin or eye irritation and may affect  long term health if inhaled or  ingested. The primary and most serious adverse health effects include kidney dysfunction, lung cancer and prostate cancer. Its use is now restricted in the UK to the defense industry only. With this in mind  always wear a mask and wash your hands after handling the links.

As I operate a business I will always send these links off to a specialist company who will replate them in gold passivated zinc.  Whilst this might not suit the purist it does ensure that the unit is safe in operation and you can pass it down to your children with impunity!

Dismantling

 

Before you start make sure you have a variety of sealable plastic bags to store all the components safely.

First up is the removal of the motor. Start by removing the long bolt holding the spark suppressor. It should come away with two plain and one grip washer and a nut.

 

Next remove the cover from the top of the switch which will allow access to the terminals. These just lift of their lugs. Remove the small bolts holding the switch assembly and store safely.

 

Looking at the speed adjustment knob, remove the nut and bolt from the clamp and gently lever the link off the spindle. Pull the knob off and recover 3 plain and one tension washer.

 

With a large flat screwdriver remove the 3 machine screws holding the motor cage. You can now remove the motor cage together with the speed adjustment arm and wiring.

 

Using a small bladed screwdriver slacken the 3 (or 4) grub screws on the motor pully and speed control disc and pull off the spindle.

 

The speed control magnet and lever are held in place by a split pin. Using a screwdriver and pliers bent the ends back straight and remove the pin. Remove the magnet assembly together with the control lever and recover the split pin, a spring and two washers.

 

It is worth noting at this point that some parts will be covered in grease and that some washers can be missed so dig around in the grease to find that last washer and make copious notes of where things go. I have found a few differences in these turntables with regard to washer positioning and can only conclude that some have been lost along the way during poor rebuilds.

 

The on/off lever and speed change levers can be removed next by removing the clamp bolts and tapping the shafts through using a drift and small hammer. You should find one washer between the head of the lever and top of the turntable. I have never found one on the underside between the base and the clamp but always add one when refitting!

 

Unhook the tension spring between the “trigger” lever and the on/off lever and set aside.

 

Remove the cage holding the speed change mechanism by removing the 3 nuts and bolts  together with washers, rubber isolating bushes and brass spacers.

 

Remove the pivot bolt (near where the capacitor mounting hole is) with 2 washers, nut and spacer bush.

 

Both levers can now be lifted away with the cage and all can be separated easily.

The remaining trigger lever (as shown in the photo below) is held in place by a copper rivet and this can be removed by drilling out from the top using a 3mm drill. Drill only into the soft copper and do not drill right through. Finish removal of the rivet with a small punch or drift. Retain the washer and spacer bush but discard the rivet.

 

Lastly remove the main bearing housing held by 3 machine screws and nuts and set aside.

Note

There are 3 options for refitting the trigger arm when the time comes:’

1) Reuse the old rivet ........... Not easy to refashion and has to be glued.

2) Use a pop rivet .............. This is the preferred option for some other companies and the easiest.

3) Replace the rivet with a new copper one ...... My preferred method and not too difficult to do!

Shown on the right is the speed change cage minus the shaft and cam which is connected to the speed selector lever. It carries a cast aluminium arm which holds the rubber drivewheel in its bronze bearing. To replace the bearing and re-plate the metalwork this cage has to be totally dismantled. Look out for the washer often stuck with grease to the plate and the 3 brass bushes inside the anti vibration rubber mountings. As the metal items are to be re-plated I also remove the spring on the locking mechanism. As a replacement set of springs is purchased as a set this spring is automatically replaced although I have never found one to actually need replacement.

The Motor

 

The motor is suspended in a cast alloy cage by 6 springs. These are held at each end by a steel pin and two “e” clips. These are often wrongly referred to as circlips by some and can be prized off their pins with a small jewellers screwdriver. I remove all the clips and pins as I replace the springs regardless off condition but this is only because I purchase a full set of springs prior to each rebuild.

 

You will notice each spring has a rubber sleeve. These are to dampen any oscillation within the spring and should be supple and reasonably tight fitting. I always replace these with new rubber tube with an internal bore of ¼ inch or 6.35 mm.

 

The motor is constructed from two alloy castings held together by two long studs. If you want to dismantle simply remove the two nuts and grip washers (shown painted red in the photo) from the top section and lift the top off.

 

The bottom half holds the two coils and terminals and the lower bearing. The commutator shaft pulls straight out and the end of the shaft can be inspected for wear although there is nothing to be done as refurbishment would be prohibitively expensive. The shaft in the photo is typical, showing wear to the centre and is to be expected after 50 or so years.

The lower bearing consists of a bronze bush and a captive stainless steel ball. This is surrounded by a felt washer (identical to the one on the top of the main bearing)and spring washer which then sits in an oil reservoir/cup which is riveted to the body with 4 small copper rivets.

The bearing and ball will be covered in gunk which should be cleaned off so that the ball can be inspected. It is unlikely that wear will be apparent but if the ball shows a flat spot it will need to be removed and turned round. If it is OK it is only necessary to fill the bearing with oil and leave it to soak for as long as possible.

If you decide to dismantle,  the rivets need to be drilled out by carefully removing the tops with a 3 mm drill and punching through with a drift. The bearing retaining spring is quite strong so be careful that it isn’t lost when you remove the cup. Having dismantled the bearing, clean with WD40 or sewing machine oil and then recharge the felt washer with 3 in 1 oil and reassemble. New rivets and a setting tool are available from Perfect Sound. In my experience it is very difficult to refit these rivets and keep everything aligned and the oil in place as there is a lot of fiddling required. A solution to this is use bolts in three of the holes while a rivet is fitted  in the fourth. Bolts can be removed in succession until all rivets have been refitted. I suspect that bolts and nylock nuts would be a very good alternative solution to rivets if keeping everything original is not something that concerns you.

Having completed this part of the work I fill the bearing with oil and set it aside to soak until all the other jobs on the turntable have been completed.

I have found that the top bearing is not quite so dry as the lower one so I leave this in a shallow oil bath. The bearing material is designed/manufactured to be slightly porous so a good soak should be sufficient to recharge the internal felt washer.

 

Prior to assembly I check the field coils with a meter

 

Under the bakelite cover are two terminals for the mains supply and four pins connected by two wire links which are used to configure the motor for 230 or 110 volt operation.

 

In your head mentally number the pins 1, 2, 3 & 4.

 

In 230 volt operation the wire links are used together across the two centre pins (3 and 3) which puts the two coils in series with each other. The resistance across pins 1 and 4 should be 460 ohms.

 

In 110 volt operation  the links are used between pins 1 & 2 and 3 & 4 putting the coils in parallel with an overall resistance lowered to 115 ohms measured at pins 1 and 4.

 

Without the links, measure the resistance across pins 1 & 3 and 2 & 4. These measurements should be the same at 230 ohms.

 

Measure the resistance between any pin and the body of the motor. You should not be able to register any connection here unless you have a short in the coils. All being good the motor can be reassembled and tested.

To assemble give the bottom bearing a last look at a drop of oil and insert the armature. Locate the top cover and secure with nuts and grip washers. Twist the spindle by hand whilst tightening the two nuts. You should not find any difference in the spindle once all tightened up.

 

Fit the mains lead to the bottom two terminals and connect the earth wire under on of the nuts. I form loops in the wire and solder to form a ring for the mains connections and use a proprietary tag for the earth.

 

I found the following procedure  on the net . --  It is not really necessary and is dangerous and should only be carried out by a competent person as any mistake can result in an electric shock.

Ensure that your electrical supply is protected with earth leakage circuit breakers before proceeding:

To operate the motor use a clip to tie the two switch terminals together and wrap the whole temporary join with insulation tape.

Ensure that the terminal cover is fitted and secure and make a final check of the taped up terminals.

Connect the motor to the mains supply and switch on. With the motor running slacken the nuts slightly and holding the two halves of the motor twist slowly back and forth whilst listening to the motor. It is possible to find a sweet spot where the motor is at its quietest.

 

Finally the motor can be hung back in its frame. I use new springs supplied by from Perfect Sound, but I prefer to use an electrically conductive rubber tube for the dampeners. I mount the springs in the frame first and then connect the three top (shorter) springs first followed by the lower three. It is easy to loose “e” clips in this process and I always end up replacing one or two! To lubricate the springs and pins I use a teflon based grease which will not attack the rubber sleeves.

 

With the motor in place I fit the eddy brake disc and pully taking care to tighten the small grub screws equally. The magnetic brake assembly is fitted using a new split pin and graphite loaded grease.

Main Bearing

Both the grease bearing models (pre 1956) and oil bearing models use the same components for the shaft and thrust bearing. The differences are in the housings where the grease bearing has a brass cup or charger for the grease and grooved bronze bushes and the oil bearing has Oilite bushes and a felt oil pad to feed the top bearing bush. There are variations to this however with some grease bearing models having cast iron bushes and bronze being used on some oil bearing models.

I have found significant wear to the top of a grease bearing model but when cleaned and then recharged with grease the slackness no longer appears to be a problem. It seems that the grease bearing models were made slack so that the grease would reach each part of the bearing.

Your local Precision engineering company will be able to advise.  

 

The shaft was turned from mild steel and then case hardened. I usually see a small mark on the base which is normal wear. As the thrust bearing is domed slightly this wear is unavoidable and acceptable.

I do not recommend replacement of the thrust bearing with a small ball bearing alternative as wear to the spindle will only increase.

 

Lubrication:

For the grease bearing I prefer to use a 50/50 mix of automotive axle grease and Graphogen which is a mix of colloidal graphite paste and oil. I have found that it negates any slack and does not reduce start up times significantly.

 

For oil bearings I prefer SAE30 oil such as Castrol Magnatec 5W30 or 3 in 1 Motor oil which was developed for heavy electric motors and is a SAE20 oil.

If after cleaning the bearings and shaft you think that the fit is sloppy then use the thicker oil. I would experiment with thicker oils to stave off the day when the bearings have to be replaced.

Idler wheel and bushes

The idler wheel is held in a cast alloy cradle which is attached to the speed change mechanism. The cradle has a pressed steel arm screwed to the top and together they hold the bronze bushes that the wheel runs in.

Later Garrard 401 models used a wider cradle assembly which is superior and can be fitted as a direct replacement on the 301.

The bushes always require replacement and a kit is available from Perfect Sound (UK) or Audiosilente (Italy) consisting of the bushes, a drift and two small rivets and setting tool.

The lower bush does not support the weight of the wheel, instead a small plate of spring steel is held in place by the two small rivets. To remove the lower bush tap out both rivets using a small drift and remove this plate. You could remove just one rivet and swing the plate to one side but it is easier in the long run to remove it completely.

 

Tap out the old bushes from the cradle and top plate. At this stage you can insert the new bushes and refix the bearing plate with the new rivets supplied. You will in all probability find that the wheel will be stiff in use and will not spin freely. It is possible that the top and bottom plates are not aligned correctly due to manufacturing tolerances or that the bushes have distorted slightly when they were inserted. To prevent this I re-assemble the cradle before fitting the new bushes and with a reamer I very carefully clean out both holes together so that the two holes are perfectly aligned before fitting the bushes. If this is not done then, when the wheel finally does bed in and runs free it will be in an elongated hole and the working life of the bushes will be reduced.

 

The wheel is checked for flat spots in a lathe and given a fine sand with wet and dry 600 grit paper before fitting in the cradle.

Linkages

 

The links and associated metal parts are plated with Cadmium which is a heavy metal. Cadmium is dangerous and can cause local skin or eye irritation and may affect  

As I operate a business I will always send these links off to a specialist company who will re-plate them in gold passivated zinc. Whilst this might not suit the purist it does ensure that the unit is safe in operation and you can pass it down to your children with impunity!

If you don’t want to remove the plating then clean only in warm soapy water, dry and spray with WD40 or similar and wipe off. This will reduce dust whilst you are handling the links and re-assembling the turntable

Chassis

If you go as far as a total strip down and repaint of the chassis it is worth getting the chassis sandblasted. There are a variety of coatings available but the most appropriate are either spraying with a 2 part epoxy paint system as used in the motor repair industry or electrostatic powder coating.

The blue chassis was powder coated and is a great success. The finish is not perfect and shows all the defects present in the original (poor quality) casting but it looks totally natural and retro and in my opinion is more in keeping than one with a  perfect finish. In fact the quality of the casting is so poor that this chassis was stripped and recoated 3 times in order to get an acceptable finish.

For the purist the best option is a repaint in old english white in a modern epoxy paint finish.

Reassembly

Legend Plates

If you have repainted your chassis the legend plates will need to be refitted using new rivets and a setting tool (shaped punch) either in a special press or in my case a pin hammer. I reuse the existing plates and new rivets in most cases.

New plates are available from Perfect Sound but only in black.

Reassembly

t is possible to refit the plates and set the rivets with ordinary common hand tools and it is advisable to use an assistant whatever tools you have available. I use an assistant to hold the chassis upside down over a piece of hardwood. One rivet is placed in position and with the assistant pressing the chassis down very firmly the rivet can be set with a centrepunch and mallet. Failure to keep the chassis held down can result in the rivet expanding in the wrong place i.e. between the legend plate and the chassis. It is worth purchasing a few more rivets in case this happens!! Set each rivet in place and finally check each one for tightness. I find that I have to strike the setting tool about seven or eight times before the rivet is sufficiently tight.

 

Trigger Arm

 

As posted under dismantling there are 3 options for

refitting the trigger arm. I prefer to replace the rivet with a new one.

The arm is left to swing on a small spacer and under a washer. I grease the spacer before setting the rivet in the same way as the legend plates.

Main Bearing

With all the rivetting work out of the way I prefer to fit the bearing next simply because one nut is difficult to access after the speed change assembly is fitted. Fit just the sleeve at this time leaving the shaft until later in the rebuild.

Speed Change Cage

 

Assemble the cage and links, remembering to fit the washers in the same position as they were removed. The pin holding the cam has a flat on one side so you cannot make a mistake on the positioning of the link. Refit the strong spring to the cam locking mechanism and the longer and weaker return spring for the idler wheel carrier. Fit the idler wheel carrier with its circlip and connect the spring. I like to paint the ends of each spring with red paint just to "stick" them in place as is stops any rattles in use. All moving parts are lubricated with silicon bike grease!

The cage is held on 3 rubber isolating grommets which should be replaced as they go hard over time. I have found that available  replacements are too hard so I have sourced my own with a Shore hardness rating of 50' although buying in small quantities is extremely expensive!

Fit with the 3 long bolts, sleeves and washers remembering that the cage "floats" on the rubber grommets.

The pivot to the link is held by a bolt, spacer, washer and nut and the end of the linkage is held to the spindle of the speed change lever by a clamp bolt.

On/Off links

 

These are in four parts which are riveted together in two places. Together the assembly is held in place on a chassis pin and circlip and provides an interlock which prevents the user from changing speeds whilst in operation, operates the switch and pulls the idler wheel into contact with the motor pully. At one joint there is also the brake arm which can be adjusted to operate (or not which is my preferred option) and is self explanatory in its simplicity. The assembly works in conjunction with the trigger lever and tension spring (not shown in photo above).

I use silicon grease on the post, the trigger lever and the interlock mechanism.

Fit the tension spring between the trigger lever and links at this stage. A tiny screw on the arm near the pivot post provides final adjustment of the assembly and should only by tightened when the switch is fitted and you are ready to test the operation of the levers.

Fit the on/off lever with washers top and bottom of the chassis and clamp with the machine screw and nut.

Finally, fit a new spring between the idler wheel carrier and the arm assembly.

General view of top with bearing housing fitted prior to fitting the motor, switch and speed adjustment knob

Speed adjustment knob

 

The motor speed is regulated by a magnet which acts as a brake on the eddy current disk. It is held on a post which is permanently fixed to the body of the motor. The magnet assembly sits over a spring and is held in place by a washer and splitpin. To this part is attached an arm which holds a small disk drilled with 3 holes. This disc sits over a small spacer in the same way as the trigger lever and is free to spin.

As the links are plated this part of the assembly is dismantled and rebuilt with a new rivet to avoid it sticking in the replating process. A suitably sized bolt and locknut would do instead of a rivet.

Three new springs are fitted first to this disc and then to the larger speed adjustment link. This is a fiddly job so take your time and don't stretch the springs. When fitted I dab a bit of red paint on each loop as an anti rattle measure.

Fitting the Motor

 

The motor is held by 3 machine screws and is fitted with the speed adjustment arm, switch assembly and suppressor.  To neaten the wire to the switch fit the switch body first then the motor (3 machine screws) and suppressor (one long bolt) and then plait the switch wires before finally fitting the brass contacts over their respective lugs on the switch base.

Fit the control knob through the chassis with washers top and bottom as before and fit the speed control arm clamp with machine screw and nut.

I use a silicon thread seal on the 3 screws holding the motor cage.

When fitting the suppressor be careful to rotate it to a position where it will not foul the toothed interlink of the on/off mechanism.

View showing the main bearing, speed interlock, speed adjustment arm with its new springs, switch and spark suppressor.

Note the chassis post where I like to use a piece of heatshrink tubing which lessens the "clunk" from the mechanism in use.

Main Bearing

 

The bearing can now be fitted in its shaft. Working from underneath, lube the shaft and pin before inserting. Insert the thrust bearing and spacer (if fitted) and clean the mating surfaces of the shaft and bottom plate before fitting the gasket. Secure with the two bolts and grip washers. If the gasket is damaged you can either purchase a new one from Perfect Sound of use a silicon gasket/sealant as supplied to the automotive industry.

 

For the grease bearing I prefer to use a 50/50 mix of automotive axle grease and Graphogen which is a mix of colloidal graphite paste and oil. I have found that it negates any slack and does not reduce start up times significantly.

 

For oil bearings I prefer SAE30 oil such as Castrol Magnatec 5W30 or 3 in 1 Motor oil which was developed for heavy electric motors and is a SAE20 oil.

If after cleaning the bearings and shaft you think that the fit is sloppy then use the thicker oil. I would experiment with thicker oils to stave off the day when the bearings have to be replaced.

Platter

The Platter does not require much work and unless you want to repaint it all that is required is to clean the inside "track" with a very fine wet and dry paper used wet to remove any marks. I have used a black stove paint from a rattle can to good effect by mounting the platter on its bearing and sparaying the edge whilst it is spinning. When dry sand back the paint to expose the strobe marks.

 

 

THE END -

I may add refinements to this page at a later date. I hope it has been useful

If you found this piece helpful please buy me a pint. Thank You!

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