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Saturday, March 29, 2014

NAD 5120 or Tesla NC470


I got back into vinyl records via my son, who started to collect LPs and i decided he should get a turntable as a surprise Christmas present back in 2011. I was an avid audiophile in the late 70s and my father had a great system,including a Thorens deck. With the arrival of CD, I whole heartedly  embraced that format and hadn't owned a deck since around 1981. I decided that a decent but cheap second-hand deck would be ideal for my son, it wasnt a main present, more a novelty to see if he liked the format, so i didnt want to get a more expensive Thorens or Rega, brands i remembered from my past. Why my son had started buying vinyl without a deck I'm not sure, I think he liked the aesthetic and tactile element of LPs, which i completely understand.

Looking on ebay, many of the decks i remembered were going for high prices second hand, and in the end i bid for and won a humble NAD 5120 . I looked for decks close to where i lived as i reasoned that without the original packing, delicate turntables wouldn't travel well. The price was good, around £20 i recall, and the seller was quite close to me, so i collected it. I had a vague memory of the NAD having some strange flat arm, and looking unlike other decks. I also recalled visiting Brighton around 1980 , and popping into a Hi Fi shop ( when such things were common), which stocked the NAD brand. The salesman was talking to a customer about the new wonder-amp, the NAD 3020, which was getting rave reviews and being coupled with very high end turntables including the Linn Sondek LP12. The salesman, as i recall, lowered his voice and said that NAD were going to bring out a Linn-killer deck for £100, and it was being built "behind the Iron Curtain", hence cheaper production costs, and the customer should delay any purchase til it came out.

It was a long time ago, but it stuck with me as I remember thinking "good"  - Linn were the darlings of the magazines and their dealers were zealots who rubbished anything which wasn't of that brand. I hated them.
Fast forward to December 2011 and I had a NAD 5120 , purchased secretly as a surprise for my son. I needed to test that it worked. I had an A&R Cambridge A60, which had a dedicated DIN phono input, and a pair of RAM 200 speakers, both of which belonged to my father and I helped choose with him. the speakers were made around 1980 by RAM, a long gone but fondly remembered British speaker manufacturer from Norfolk

The deck came with an unidentifiable cartridge so i ordered a budget Audio Technica AT95 on-line.

I'd heard the deck play when i collected it and it seemed OK though there was a little hum.

Its Czech , and its a Tesla !

I was immediately struck by how different this deck was in design. Substantially
 plastic, though its substantial plastic, with a very strange flat arm featuring a balance weight on a spring with an oil damping container on the arm; a lid with no end pieces, just high side "cheeks" on the plinth, and a strange platter that seemed to also be a mat. All finished in the NAD dark olive green . This truly was unusual, like a Citroen 2CV is an odd car.

I did some research on the web, mainly the wonderful vinyl engine web site and its associated forum, which has many friendly and helpful members.

I discovered that the deck was in fact a Czech design and in fact was simply a NAD re-badged version of a turntable widely sold on mainland Europe as the Tesla NC470, built in the Tesla Litovel factory in what was then Czechoslovakia. The designer was  Jiří Janda , about whom I could find very little, but some of his patents are here

He  developed a number of audio products under the noses of the authorities in then Soviet-era Czechoslovakia through Audio clubs where members effectively made amps and equipment as part of the club. It also appeared that many of his ideas went into the deck, built by Tesla, who perhaps were a distant relative of Pro-ject, one of the few remaining turntable manufacturers in Europe. It was intriguing and part of the purpose of this blog was to try and find out some more history of the development of this deck. Perhaps someone out there knew Jiri or worked on the development of this deck, if so I would love to hear from you. I did find out that Jiri died in 1993, a short obituary can be found here  , and a few pictures of him exist on the web and he looks a very kind man.

So i guess that the old saying that, necessity is the mother of invention, was true with this deck. I have come to appreciate just how clever the design of this deck is, and I guess that , where a material,technology or method was unavailable , a clever alternative was figured out. That flat arm, with its anti-resonance balance weight being a case in point.

I also discovered that while NAD actively promoted the deck as having a floppy arm, they later appeared to loose faith and reverted to a more conventional round arm for the deck.

( Actually the arm is not floppy, its made of a ruler shaped piece of circuit board, and while it can be flexed , this is not normal, indeed the adverts NAD had showed it being bent over. do not do this as it will do no good to the copper tracks along the flat arm).

So you can see examples on ebay with both a flat arm and a round tubular arm. You can even swap arms as the arm simply plugs into a 4 hole socket which also forms the vertical bearing. Over time I have had a number of these decks pass through my hands in addition to the original flat arm example, as i have acquired spares and repairs decks to try and get them working.

Variations on a theme

Im not sure what the start and end dates of the production of these decks was, id guess from the early 80s to maybe the late 80s. Variations i have encountered are :

  1. Original flat arm model with orange bulb at front. Inside a DIN socket plug is used as a solder junction between the fine wires from the arm bearing to the signal cables. Sub chassis can be levelled using plastic washers as shims above the primary suspension springs and their rubber bushes.
  2. As 1. But with a round tubular plastic arm
  3. As 2. But the orange light bulb at the front is replaced with a Red LED and one less wire is needed to provide power to the front light.
  4. As 3. But additions include no longer using a DIN socket as a junction, but has moulded turret tags at rear right of deck. Also suspension springs can be adjusted via screws from below. Improved grounding arrangements in arm pillar reduce hum using a staple shaped metal insert to ground the arm pillar through its horizontal bearing.
In addition to these , i have found some minor differences in the arm and spindle bearing arrangements. Some examples sit the bearing on a tiny blue metal disc, size a hole-punched chad and housed inside the base of the brass and black plastic bearing sleeve assembly, cleverly common to both arm and spindle . Others used a nylon disk, and others no disk at all. Blue metal disks in both bearings is best for ground continuity.

One example I had had a staple-like metal link inside the arm pillar to improve the grounding from the external arm pillar metal case, via the arm horizontal bearing to the sub-chasis.

As far as im aware the only difference between the NAD and Tesla models was the badge and maybe the colour of the paint used ? not sure if Tesla sold the deck under their brand before NAD got involved or after, I do know that if you attempt to clean the plastic upper chassis of a NAD unit with alcohol, the olive green paint comes off revealing a more metallic grey underneath. I wonder is this was the original Tesla colour, and NAD just resprayed them ?

There is another variant which was sold as the Lenco L800, which looks to be a flat arm unit except that the upper half of the plinth was made from wood rather than plastic. I've only seen pictures of this, never seen one, but would be tempted to get one.

Generally the decks hold their value well on ebay, perhaps partly due to the NAD brand, with the tubular arm models occurring more often than the flat arm. In the UK you can get an example for around £40-70 depending on condition. Indeed honest sellers often advertise them as non working due a number of common problems :

  1. Speed selector not working. The selector doesn't cleanly nudge the belt to the correct part of the motor pulley
  2. Automatic function doesn't work. The Deck has a simple auto raise and turn off feature at the end of a side, this seems to work on some decks and not on others. Its nicely done and doesn't appear to interfere with the functioning of the arm either way
  3. Motor randomly turns either way. This is sometimes due to a bad phase capacitor. If the deck always turns the wrong way or has trouble holding speed, it could be a bad motor winding.

What is inside ?

First disconnect from the power, and i mean disconnect at the wall, don't rely on the power switch at the front, as the motor is always partly live.

So getting back to the run up to Christmas 2011, when i finally fitted the cartridge, aligned it, and tested it in secret, I had music through one channel and loud hum through the other. If this was to be a success , I needed to figure this out.

Despite the decks largely plastic construction,its well made, the plinth is in two sections , held by 3 Philips screws. I have taken my decks apart in excess of 20 times and not stripped any threads. I would say the plinth is less resonant than other plastic decks from Dual and various cheaper Japanese Direct Drive models.

So to open the deck up you first remove the lid, which slides out of the two rear hinges. The hinges pull out of their slots. Next you can remove the whole arm, it pulls away from the pillar at the point where it pivots. This requires some care , and if you have a stylus plastic guard or cover, its worth applying that first.

Next you can remove the mat which is rubber with an inner plastic insert which has one of those 45 adaptors for DJs in the middle. The mat is unusual in that its also substantially the platter. These mats often discolour becoming a snowy grey colour, but washing and cleaning with platanclene rubber restorer will bring them up like new. Beneath the rubber mat-platter is a simple pressed steel sup platter which has an upward facing lip which engages in a trough on the underside of the mat.

The painted steel sub-platter comes off revealing another sub-platter made of plastic which has the spindle passing through its centre. This looks similar to sub-platters found on Pro-ject and Rega decks. Between the two sub-platters sits a humble and unnoticed copper foil washer which helps to provide a ground between the steel plate and the spindle. You notice the paint is removed so the washer makes a good contact.

The plastic sub platter can be removed , the rubber belt fits around this. Pulling the sub platter out by the spindle reveals the main bearing, which is narrower than the spindle. Many decks these are the e same or larger diameter. As with everything you remove ,these pieces should be placed somewhere safe and ideally soft, as the main bearing should not be scratched or damaged.

Now you can remove the upper part of the plinth as you should be able to clearly see 3 Philips screws around the circular central recess. Once removed and safely stored,you have the problem of separating the upper half of the plinth from the lower. Gentle steady pressure with the fingers through the circular recess into the base i find works. Gently ease the top plinth away from the base. Eventually it should come free, and again place it somewhere safe.

At this point you should be looking at the black plastic base with all the wires , levers , springs and metal sub-chassis

At the back left you have the AC synchronous motor, held in place by two brackets which also act as guides for the speed selector contraption, lets call it a sled, as it slides. AC motors spin at a single speed, and the tiny aluminium spindle connected to the motor sets the platter speed. The belt is guided between two diameters of the pulley when changing speed, rather like the de-railer  gears on a bike.

Centrally you have a metal sub-chassis which sits on 3 large springs via 3 rubber mounts. To the sub-chassis is attached all manner of bits, but the main things are the main bearing housing, that the spindle sits in, and the arm pillar, a fat circular metal tower on the right. It rotates with the arc of the arm, limited by a screw in a slot at its base. The sub-chassis normally 'floats' when the full platter system is present due to the compression of the springs. With the platter etc. Removed the springs force the sub-chassis up, but its limited by a locking wheel located beneath the deck. You can tighten this when shipping the deck to restrict the movement of the sub-chassis, loosen when its in its intended location.

There are two sets of wires in the deck. Power to the motor which is mains i.e dangerous , and signal wiring from the cartridge which are not dangerous. The mains cable enters at the rear of the deck and snakes around the partitioned wall to the motor, with further wires passing around the front of the deck to the switch at the front. Close to the motor is a silver phase reversing capacitor. Its function is to start the motor right direction as AC motors can turn either direction. A second suppression capacitor is located at the front by the mains switch and light bulb. The deck has no safety earth, but this is not uncommon and does not mean the deck is necessarily any more dangerous than any other household appliance, assuming its not been tampered with or modified.

The tiny thread-like wires emerge from the base of the arm pillar. These carry the signals from the cartridge via the arm. These wires are extremely delicate, as , by necessity, they are thick enough to carry the signal but thin enough to not impede the movement of the arm. These connect to the main signal wires either using a DIN socket as a junction, (no idea why ? Love to know, maybe for easy testing in the factory ?) or in later models via some solder tags moulded into the deck base. Conventional signal wires take up the audio story and snake around the back of the arm and snake around various partition mouldings in the outer wall of the base moulding.

A ground continuity wire also emerges at the same point from the deck, its anchored to one of the three screws at the base of the arm pillar. Its role is two fold, to ensure ground continuity from the deck to the preamp to avoid hum loops, and also to ensure electrostatic continuity from the spindle to a static point. Phono sections on amps usually have a binding post to attach this wire to.

There is a mechanical linkage from the front switch to the arm raiser and various springs and pulleys, some of which provide anti skate from the arm support arm, others provide the hit or miss auto raise function.

Now lets jump back to my sons deck. its now December and the big day is approaching and this deck is far from working. I have hum only on one channel . I decided that i must have an issue with the arm wiring, and gently tugging the coloured wires emerging from the base of the arm revealed that the blue one was not connected to anything.

I'm quite a practical person, and have some modest skill at soldering so I'm not too intimidated by these issues.

I realised that i needed to remove the arm pillar, and its held captive by a bolt in the curved slot at its base. Once this is removed you can carefully slide the whole arm pillar off its bearing. This reveals the same brass and black plastic bearing sleeve as the platter spindle uses. Neat, never seen this approach taken anywhere else. This is fiddly work as the heavy, substantially metal arm pillar is now only captive by 4 cotton thread-like wires, or in my case by only 3.

The wires solder to the base of the plastic socket the arm plugs into. The socket has two spikes which emerge from either side and sit in two cupped grub screws accessible from the outside of the arm pillar, forming the vertical needle bearings. Loosening the grub screws, only a little and the same amount on each side, eventually lets the socket piece loose of the top of the arm pillar and you can get at the solder tags on the base. However there is very little slack and these wires are hard to work with. I couldn't resolder the blue wire and ended up making things worse.
In the end i decided to run 4 new wires from the socket base to new RCA sockets which id fit to the back of the turntable base. Trouble was which wires to use. In the end i used computer mouse wiring which is very thin but not too hard to work with. This worked but was still a bit stiff for my liking , causing i felt some tracking issues with the arm, so in the end i got some fine Litz wire from ebay especially for arm rewiring, which is finer. This is all very fiddly and i have to say that unless you have a specific issue with the arm wiring , id leave well alone as :

  1. The wires are fine and the soldering is hard. If you overheat the tags on the base of the arm socket you could deform it.
  2. Loosening and tightening the side grub screws for the needle bearings is hard to judge. Too tight and the arm doesn't move freely, to loose and there is arm play.

The only other thing i have done on some decks is to lubricate the motor bearing. Again i emphasise that these decks carry live voltage, so only attempt this if the deck is disconnected and you are sure you can safely work with such devices.

On two decks i had noisy motors. The motor is clamped in place but what appears to be a black plastic thrust bearing protrudes from the base of the motor and through a hole in the base of the deck. Several of the decks I've seen have had the black bearing cap mangled. I assume owners have either :

  1. Tried to remove the plastic cap with pliers. Don't , its doesn't come off from the bottom, you have to open the motor to get at it
  2. Forced the motor stator down to try and reduce speed changer noise and unwittingly popped the tiny thrust ball bearing out through a tear in the base.

The correct way to clean and re-lubricate the motor is to remove the motor from the base, by removing first removing the motor spindle which is held in place by a tiny diagonal grub screw from the top, then remove the speed selector frame and its guides. They are held in place by two screws which pass through tags on the sides of the motor. The wiring from the motor has some opaque silicone sleeves to protect it .
If you remove the motor, beneath is a small circle of yellow foam rubber which provides some modest decoupling of the motor from the base.mi have tried replacing this with sorbothane rubber and got much more noise, so stick with the original foam, but it might benefit from a wash in warm water And a gentle dry in the sun.

Once you have the motor out, still captive by its wiring you can obtain more slack by removing the clip-on black plastic box section which protects the motor wiring. With now adequate slack, if you examine the seam around the edge of the motor there are 3 small slots into which you can get the blade of a screw driver into. By gentle and progressive twisting action you can slowly prise the two clam shell halves apart. The trick is gently and do a small amount of twisting in each slot. Too much in one slot and you'll warp the motor shell. Gently and slowly is the trick. After a while the two parts separate and you can access the central stator, and pull it clear of the two halves.

The lower spindle engages with a lower thrust bearing. That black plastic thing is a tiny well with a ball bearing inside.. You don't need to remove the plastic piece from the motor, but i found i could twiddle a wooden tooth pick around inside to remove dirt, then soft rag twisted in. Finally a small grain of rice sized blob of silicone grease. The upper bearing is a simple collar bearing and again a little silicone grease is fine, but make sure the rest of the stator is clean. In all the motors I've seen the motor is very clean inside.
Putting it back together her is a case of reversing the process. The two sides will only go one way with the wires together. Once in position gently squeeze the two halved together with grips, gently and again, a little rotate, a little rotate, a bit more, till the two halves are tight together again. This motor self centres, so you should find it spins freely after this process.

Much of the above is explained in a video I made of the repair of a noisy NAD motor, including the disassemble of the deck


peter said...
This comment has been removed by a blog administrator.
peter said...

Excellent article, thanks.
I have just been given a 5120. The plastic sub platter is very stiff and really not happy to be rotated by hand. I tried pulling it up but I'm wary of how much force to apply. I know it was in storage for a while. Not sure how to proceed. Shall I just twiddle the platter round and see it it frees? Can't see any other way of getting under it. The sub platter is rotating on the spindle, should the spindle not rotate?
not sure if my comment got through

Mr Ives said...

Thanks Peter,

Hmm, well it sounds like the spindle is pretty stuck inside the bearing well. So I assume you have removed the mat, and the pressed steel outer platter and you are looking into the recess at the centre of the deck. there is a brown sub-platter with a metal spindle emerging from its centre. This sub-platter and spindle are bonded together and the sub-platter should not rotate around the spindle. The sub-platter and spindle should easily pull from the bearing as its not held captive normally.

If you screw the shipping dial underneath this anchors the sub-chassis, you should be able to grip the spindle and pull, perhaps with some pliers with some rag in the grip to avoid scratching the spindle.

Some old grease may have hardened in there.

Alternatively you could remove the whole subchassis and remove the bearing from beneath, but that’s a long and fiddly process and the deck has a number of small springs which tweak the position of the sub-chassis.

I You can actually remove the upper part of the plinth too, its held on with 3 screws, and can be removed with the sub-platter still in place. This way you might be able to get some freeing oil into that bearing from the side with a straw or metal rod.

I hope this helps.

peter said...

The sub platter really doesn't want to come out! I've taken the top half of the plinth off and I'm giving the bearing a squirt of penetrating oil every day. It will come off eventually!
It's a nicely engineered unit, a lot of thought went into its design.
I'll let you know how I get on and thanks for your help

Mr Ives said...

Thanks Peter.

If you are really bold, having removed the top plinth, also remove the arm, it pulls off at the pillar, using a 4 pin socket.

Now if you remove the Cir-clip on the locking wheel beneath, you can actually remove the whole subchassis. A few small guidance springs have to be carefully unhooked.

If you do this you can get at the 3 nuts under the subchasis which hold the main bearing carrier to the sub-chassis. NOTE this innovative deck, as you point out, uses the same carrier for the tonearm

Anyway you can loosen and remove the three nuts at which point the sub-platter, spindle and main bearing carrier should come away. The underside of the bearing is now open and you could get some penetrating oil in there. and hopefully get the spindle out.

peter said...

I've done all that. I can see what has happened now I think. At the bottom there is a ball bearing and a brass sleeve. I imagine the shaft is supposed to rotate within the sleeve but it doesn't. If I grip the other end of the shaft and rotate the plastic bearing housing, the brass sleeve doesn't rotate, the plastic rotates round it. I can't imagine how that has happened. I'll continue with plusgas, see what happens

Mr Ives said...

Wow Peter, that sounds really jammed in there. There is no ball bearing normally, the spindle is narrower diameter below the plastic subchasis than above and simply sits in the brass sleeve. Normally that spindle sits on one of the following (seen in various generation 5120)

A tiny clear plastic disc , size of a hole punched piece of paper , which sits in a recess formed where the brass tube doesnt go right down level with the sub platter in the plastic holder

OR similar but its a blue metal disk

OR nothing,mi.e the lower end of the spindle rotates directly against the sub chasis surface

Never seen a ball bearing and i wonder if someone has mistakenly put one in which has somehow jammed, or worse used something softer i.e a lead shot. Are you sure there is a ball bearing in there and its not just the lower tip of the spindle, remeber the diameter is narrower than the end of the spindle which goes through the centre of the LP.

By all means get in contact with me, im jives11 over at , if you message me there, happy to exchange pictures etc. I may have spare tiny disks and other parts.

Jonathan Banks said...

My 5120 hasn't been used for ages and having just got a new TV and stand I moved the deck and amp etc to the new shelving in the hope that I might get more use from it. I was disappointed to find that the motor had jammed though so I couldn't use it after all. It was clearly getting power but not turning. I've used your article to see how to dismantle the motor and with some grease and brute force to put the two halves back together I now have a working motor and the platter is turning once again. Many thanks.

Mr Ives said...

Many thanks Jonathan, glad this rather rambling post was useful. Listening to mine now, they are very good decks.

nostromo74 said...

Great post. I found it looking for advice on my 5120. I have the round arm, red led version, picked it up for only £7! Just needed to replace the Ortofon cartridge. It plays well but I was looking to fix a couple of issues:
The turntable nearly always starts when it's in 33rpm but can sometimes need a little nudge to get started, occasionally it starts in reverse. It is never able to start up in 45rpm, I always need to be in 33 then switch up to 45. Is this just a matter of replacing the phase capacitor, if so, what kind should I use?
The 'lift' function in the 'stop' mechanism does not lift, is there anyway to fix this?
There is a light ticking sound that comes from the turntable, as far as my ears can tell, it's not being picked up by the stylus. Is the motor on it's way out do you think?
Hope you can help ;-)

Mr Ives said...

Greetings Nostromo74 ,

thank you for your kind words. You got a bargain for £7 !, the hinges alone on ebay can go for £20 as they are the same as the Linn Sondek hinges which seem to be in demand. The arm too will fetch at least £10, so no matter what happens with this deck, you are in profit I reckon.

The reverse direction is a symptom of the phase cap needing replacing which is a 250v 0.22 Polypropelene or polycarbonate axial capacitor. Maplin sell the correct value in the UK. Its a soldering job, you need to disconnect the deck from the mains, remove the arm (it unplugs at its vertical bearing), the lid and unscrew the three screws that hold the top of the plinth on. My blog has now a link to a video I did on servicing the motor and this has a lot on dismantling. The phase cap is on the left hand of the deck where the motor wires solder to some fairly ugly contact points. I don't know if you are happy soldering ?

if you have access to a a mutlimeter it may be worth desoldering the motor wires at the same junction and measuring continuity (resistance) across the 4 wires from the motor. There should be two separate circuits through the motor wiring i.e you should have continuity between two pairs of wires. if you dont have that , you have a break in the wire for one coil and the motor is half dead.

I've worked on 7 of these decks and not had a dead motor yet, but it can happen. if the coils are good, it may be worth watching my video which shows how to clean and relube the motor and get it back to smooth operation.

The motor always spins at a constant speed set by the mains frequency, 33 and 45 are simply blet positions on different radius sections on the motor pulley, and the speed changer is a bit of problem. Removing the platter will show you the motor, but it's hard to see how the belt sits, as the weight of the platter holds the sub-chassis down. If you are safe around live mains, it can be insightful to remove the top half of the plinth, then put rest of the deck back together, you can then see how the sled works with the platter in place and with the motor running. HOWEVER THIS IS DANGEROUS, as the mains wiring where the motor wires connect is exposed, so please be careful if you decide to do this, keep hands and tools well away.

the ticking, is that present with the platter removed, , then try with the belt removed ? it could be just dirt in the motor, so the video might help.

Did you replace the ortofon cartridge or just the stylus ? the arm can be used with other cartridges, and with the damping adjustment, theoretically it could be used with an extremely wide range of compliances.

I would also suggest posting in the vinyl engine forum . google vinyl engine and join the forum. I frequent it most days, and there are a lot of very friendly and expert fixers in there.

Good luck and maybe see you in the forum or please feel free to post here more Questions or your results

nostromo74 said...

Thanks for the pointers Mr-Ives.
Yes, I just replaced the stylus, not the whole cartridge.
I'm fairly handy with the soldering iron so will give that a go. I've a multi-meter as well so will test for continuity.
I've not tested the ticking with the platter or belt removed, I'll try that. If the ticking persists with no platter/belt, would that indicate a faulty motor?

Mr Ives said...

thanks Nostromo74

I dont think that ticking is necessarily an indication of a failed or failing motor, it could just be some dirt or hardened grease in the motors thrust bearing which acts like a tiny cam and raises and drops the motor spindle every revolution.

The thrust bearing on that motor sometimes gets abused. It's visible beneath the deck, and some times decks have been abused where the motor has had a heavy downforce by owners frustrated at the speed selector sled not working. Also I have read of people cutting the plastic cap to get oil in, which is a mistake as there is a tiny ball bearing in there which will get lost or shifted off centre, so its possible that the motor is not turning on a a lubricated point on a ball bearing. How does the plastic cap on the underside of the motor look, you can see it from beneath as it sits in an exposed hole ?

The plastic sub platter also has a peg which is used by the auto-raise at the end of the side, it might be the cause. it also could be the belt rubbing in a very localised spot.

nostromo74 said...

I took the platter off and the noise persists. I'll have to take it down off my shelf to have a look underneath for the cap. I fixed the lift function though! It was just a matter of raising the small metal screw on the lifter. I've also picked up a 220nf 500VAC capacitor from my local Maplin, so will get busy with the soldering iron and report back.

nostromo74 said...

Phase capacitor replaced. It's starting up and turning the right way each time. Not sure when I'll get a chance to dismantle the motor (we had twins last month!) but I can live with it for the minute.

Mr Ives said...

Great news Nostromo74 - congratulations (On your twins)

also well done on repairing the deck. The motor dismantle is not so hard but I understand. if the ticking is not really audible then I'd leave. When you said you removed the platter, did that include the plastic sub-platter with the spindle through it ? I ask as this has a peg beneath which catches the auto-raise mechanism. removing just the belt is another ay to isolate wether the issue is your motor

BTW assume your a fan of either Heart of Darkness or Alien, or both

nostromo74 said...

Thanks Mr Ives. Yep, the film.
I took off the sub platter and belt. It was noticeably quieter and I touched the plastic surround to see if I could feel vibrations; nothing. Will report back when I give it a go. Would you recommend I stick with isopropyl or could I use a bicycle degreaser to get bearings clean?

Mr Ives said...

Thanks Nostromo74,

Degreasing the bearing needs to be done with a method that leaves no residue, so I favour Isopropyl Alcohol and cotton buds. > How you clean the bearing itself doesnt matter, as its easy to wipe clean any excess, but the brass sleeve that it descends into is better done with a solvent that dries clean.

Anonymous said...

Anyone any idea what fluid to fill the glass damping fluid 'bottle' with?

My deck is as good as new as it's been sat in the loft for around 20 years. However most of the fluid seems to have either evaporated or leaked.


Mr Ives said...

Hi, I used 200,000 PST Silicone oil for Radio Control Cars shock absorbers

György Cserkuti said...

Congratulations!!! Very correct article!

Here is my page:

Oh, Jesus...
Now i see your question from 2013...
I'm working not too much on this blogspot-page. :-)

My answer:
Most likely lead over the 3,3nF 400V capacitor, which is connected in parallel with the switch. The replacement will usually solve the problem.

George Cserkuti

Mr Ives said...

Thank you György,

I appreciate your kind words , it seems these decks were most popular in CZ, HU and UK, and their value seems to be going up second hand.

I still want to find a Lenco L-800 version with the wooden top plinth, to complete my collection

Tommaso Miraglia said...

Help! I can not remove the pulley which is at the beginning of the motor, I know that there is a small screw removable with the screwdriver but I do not know how.

Mr Ives said...

Greetings Tommaso ,

The screw is a slot head (not a philips) and require a very fine screw driver. In the UK these are called "watchmakers screwdrivers" as the screw heads are very small i.e. as found in watches. However there is sometimes a small amount of enamel to prevent access to the screw head, and you need to scrape this out first. Do you have a very fine screw driver i.e 1mm wide ?

Tommaso Miraglia said...

Please, is the grey (bigger) or black (little) hole?

Mr Ives said...

Its the black hole and the screw is at an angle approx 45 degrees, as it engages with the motor spindle (the larger grey hole in your picture) so you need t0 approach the black hole with your screwdriver from an angle, if you see what I mean. I show this in the video I mention at the end of the article.

Tommaso Miraglia said...

I believe that after so many trials without success the screw head is ruined :-(

Mr Ives said...

Greetings Tommaso, I'm sorry to hear that. Can you see the head of the screw in the hole ? Tesla put some black paint down the hole to seal it, so you might find you have to pick the paint away with a pin or needle. Then maybe put a tiny squirt of freeing oil or WD40 down the hole and leave to soak. I'm sorry this is proving so difficult

Mike Prymaka said...

Hi Mr Ives, my 5120 is working fine, but when I got it the arm (round type) was stiff in the horizontal direction. I took it apart and discovered that the vertical post that the arm column pivots on was damaged due to the movement limiting screw hole being broken. That's the vertical slot-head screw that limits sideways movement and also stops the arm column from lifting off. Resolved by cleaning up the debris and fitting a teflon washer under the arm column. Now it's a smooth as silk, but there is no screw to limit sideways movement, and great care has to be taken when removing the arm, to stop the whole lot lifting up. Long introduction to a simple question: is it possible to get a new pillar???

Mr Ives said...

Hi Mike, drop me a line jonathanDOTivesATgmailDOTcom, I have some spare parts, not sure if you mean the hefty pipe section piece that the arm attaches two or the smaller piece that the arm bearing sits in and is attached to the sub-chassis ?

Tommaso Miraglia said...

Thanks Mr. Ives, I have solved my problem with the engine without opening, but changing it with another from Ebay. Now I have two Nad 5120, I bought one in 1988 and one this year on Ebay. The two work well and is very fun to play with them, my friends look at them and say they have never seen before. They are so vintage! They should do even this, I think many would be sold. I now have three tubular arms, one does not have the damper fluid, I would like to put in, but I do not know where to find it and how to open arm as not to break it.

Mr Ives said...

Bravo Tommaso, Bravo !

the damper fluid I used was 100,000 cst silicone oil. It is sold for Radio Control Car shock absorbers, if you google search for 100000cst you will find sellers who stock it.

the small clear plastic reservoir for the oil sometimes comes off, I think it is held on with glue. It is easier to refill by removing it, then reattach with a single small drop of super glue. If it does not come off you need to dismantle the arm, remove the balance adjustment which hold the rod which extends into the oil. Then you have to refill the oil chamber through the hole. This is quite a slow job as this oil moves very very slowly.

Mike Carr said...

Hello Mr Ives, I've have a Nad 5120 turntable for many years and have recently started using it again. However, the belt keeps coming off. If I replace it it works until I turn the table off - then the belt just falls off, or if I change the speed, the belt pops off. Do you have any advice on how to ensure the belt stays in place? Even when working I've noticed it sits very low before falling off. Thanks in advance for any advice - great blog!
Cheer, Mike.

Anonymous said...

Hello Mr Ives, I've have a Nad 5120 turntable for many years and have recently started using it again. However, the belt keeps coming off. If I replace it it works until I turn the table off - then the belt just falls off, or if I change the speed, the belt pops off. Do you have any advice on how to ensure the belt stays in place? Even when working I've noticed it sits very low before falling off. Thanks in advance for any advice - great blog!
Cheer, Mike.

Mr Ives said...

Hi Mike, thank you.

yes - getting the belt to stay on can be frustrating.

a few things to check.

1) ensure the belt is very clean and dry. I tend to run the belt through a kitchen towel with some alcohol (Isoprpyl) or Platenclene rubber restorer, sprayed on it. Also make sure the outer rim of the subplatter is also very clean , as is the motor pulley

2) When you put the belt on you have to take most of the weight (mat, aluminium sub-plate and plastic inner adapter) off the platter and the suspended subchassis. Added to this weight is the weight of the record, which can be up to 200g. Hence the relative height of the sub-platter to the motor pulley changes a lot AFTER you have put the belt on. I tend to put the belt low on the sub-chassis, such that as that sinks , and the motor engages it will work its way up to the middle

3) Its possible that the pulley on the motor has dropped. It should be adjustable via a grub screw at an angle on the aluminium top. However the screw holes were filled with enamel paint. If its ever been adjusted the paint will be gone, it might be that the pulley has been dropped or that the motor has dropped. Sometimes owners get frustrated with the erratic speed change and push the pulley down which stresses the lower thrust bearing. Basically the whole motor might be sitting a tad lower than ideal.

4) The best way to diagnose what is going on is to run the deck "naked", i.e remove the top plinth and reassemble. An oddity of this deck is it runs fine with the whole upper plinth removed. basically follow the video I do, but put the arm back with the plinth and lid completely removed. You have a naked NAD !

However there is a risk as this exposes LIVE electrical wiring, so only do this as a last resort , away from children , and ideally on a bench . The wiring close to the left hand side near the motor junction is most exposed. I place my left hand behind my back, and I only advocate this as a last resort. as if you run the deck (It doesn't need to produce sound, this is just a functional test) you can see exactly what is going on from the side with the platter , mat and a record in place

Mike Carr said...

That's really good advice, thanks, hopefully 1) and 2) will do the trick

nostromo74 said...

I finally got round to dismantling the motor and cleaning it. The noise is now gone and the turntable is completely silent. There was quite a bit of gummy brown grease in the bearing. Only issue I had was not being able to get the grub screw out of the spindle, it was a flat head and looked to have had a blob of super glue dropped on it. I had to give it a good pull to get the motor spindle off but its gone back together again and seems to be working fine.

Mr Ives said...

Well done Nostromo74, glad your good to go

Carsten Seidler said...

Hi Mr. Ives and the rest of the NAD gang.

First of all. Thanks for post. Its really good!

I recently got hold on a NAD 5120 and I what to fix the tonearm auto raise.
Mostly out of pure lazyness. You listen to a record while fixing other stuff and I dont want the needle end up spinning for 10 min. or more before I get back to it.
Have anybody found a guide, know the magic words or have a picture of a working auto raise?
when I opened mine it look pretty much like picture 17.

Thanks in advance and I hope all are enjoying some good music.

Mr Ives said...

Hi Carsten,

I have had one deck where this worked and one where it didn't. Its a strange contraption BUT I think the most important thing is that there is a plastic peg on the underside of the plastic sub-platter. This peg engages with the internal rod which has a V shaped metal cutout on the end. Remove the platter then the plastic sub-platter and look on the underside for a plastic peg

Carsten Seidler said...

I can see that the pin on the underside of the plastic sub-platter is broken. Tried replacing it with a small bolt... Not a very good solution. Though if you get one in the same size. It might work…
I think the system is to turn the power off and that will engage the lifting mechanism via the power shaft. So beside a pretty difficult job of setting up the tone arm, one has the extra job of setting up the lifting mechanism also...
As I can see that most of the system broken (both pin and lifting shaft) I think I will leave as is. It was properly done for a reason…
But thanks for your help. I will get back with a replay if I find a proper solution.

Mr Ives said...

Please do Carsten, My opinion is if you leave the deck running for 10 minutes, or an hour or more , its not going to do any harm. I grew up with a wonderful manual deck (my fathers Thorens TD150 Mk 2) and I regard automatic decks as unnecessarily complicated, but that's just me . if you find a solution please let me know, sometimes people sell just the plastic sub-platter on ebay, and if I had a spare you could have it, but I don't

Carsten Seidler said...

I just got it working with some tape and a wooden shaft… It cut the power alright. I must say it looked pretty rough on the tone arm… I will leave it disabled. Think it´s better for record, pick-up ad tone arm setting.
But thanks for the offer on the sub-platter. I will leave it as I said.
Have a good one and thanks again.

fub said...

Hi there,

I can't see that anyone has actually tried this yet but I just took a punt on the Debut Carbon 230V motor to replace my well and truly ruined (bearing shot) NAD5120 motor and I am pleased to say that they are a definite drop-in replacement as long as you have some - rudimentary - soldering skills. The wires are the same colours so it's almost idiot-proof.

I bought the motor from the very helpful Henley Designs - they even got one out of a box and checked some measurements for me before I committed to buying. Just make sure you get the type M307 230v version. Cost 40 GBP plus postage.

Hope this helps someone who needs a new motor and can't find a donor turntable.

Mr Ives said...

Many thanks fub, that is invaluable information, as the NAD motors do sometimes die.

Thanks for posting

Tommaso Miraglia said...

Ciao Mr. Ives, I love this turntable (I have two of them) and I wanted to get the flat arm (I already have three tubular arms). Now I got the this but it came without the small lever to raise the cartridge and put it on the disk. I believe that it is no longer, and I decided to build one. I did search online but not find it. If you have this arm can send me some photo how to do? Thank you very much, and sorry for my bad english.

Mr Ives said...

Ciao Sig Miraglia, Your english is good, please do not apologise. I am very pleased to hear from you and am glad that there are others who appreciate this unusual turntable. I think you mean the small lever you hold to manually raise and lower the arm, this is sometimes called the finger lift ? Close to the cartridge ?

I did have one but I removed it and cannot now find it, I think I perhaps gave it to someone to complete another NAD. I found that the metal of the lift (I think it was aluminium) is very close to the copper tracks on the flat arm. These are used as the arm wiring, and the finger lift seemed to cause some electrical hum as I think it introduced a ground loop.

I also did not like it as I think it is best that the cartridge sits firmly against the headshell or arm, with the maximum surface at the top of the cartridge contacting the maximum area on the bottom of the flat arm. The finger lift reduces the contact are as it is between the cartridge and the arm.

I think it is possible that the designer did not intend to have a finger lift and this is why there is an area of white dots on the top of the arm to indicate where you can hold the arm ?

I do have a metal finger lift that is from a separate headshell and I would be very happy to send it to you for free, it is just sitting in a box of bolts and screws and other turntable 'treasure' ;) . Its not the original NAD but it will work I think. My email is, if you want to send me your address ?

Cordiali saluti


Tommaso Miraglia said...

Thanks Mr. Ives your kind reply. I bought my first deck in 1987, but I used small it was in the cd time. It is still good, and I've got another for my own other home. I believe that your words have taken away my doubt, the small lever is not useful for this arm, but for the tubular arm that has already it. Arm flat came with a new cartridge Nad 9200 and the next few days I will test it.

Thank you so much Mr. Ives for your help and for your blog and best wishes for you and your family.

Tommaso Miraglia