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Sunday, January 26, 2014

Restoring a JVC JL-A1 Turntable


Last year I acquired a Pioneer PL-12D turntable which I restored and runs very well. In the blog describing the process I mentioned that I believed that much of the content would be suitable for a wide range of 1970's Japanese belt drive turntables from the likes of Pioneer, Sony, Sansui , Kenwood/Trio etc.

 A few weeks ago I spotted another turntable being auctioned locally on ebay. The price seemed very good and I bid for it and won. It was a JVC JL-A1 which I got for a very reasonable £20 and was able to collect. The unit had been in the family from new and was in very good condition. Just a few issues due to age , namely the hardening of both rubber and lubricants with age. I had read in the vinyl engine forum that it was similar to the PL-12 and I wanted to find out, plus I enjoy working on decks.


As you can see from the pictures it is very similar. Speed change on the left (buttons rather than levers) with cueing lever on the right. S-shaped arm with removable headshell and dial anti skate.  The only significant functional difference is that the deck is an automatic, revealed by the Reject button at the bottom right.  This feature means the platter only rotates when the arm is cued at the start of the record, and at the end of a side (or when you press the reject button) the arm lifts automatically and returns to its original resting position. Magic !








I removed the mat and platter, which was a good deal lighter than the pioneer. The belt hooks over the motor spindle as per the pioneer , and can be attached via two cut-outs  in the platter.  The only difference you see are the white nylon cogs which form part of the automatic arm return mechanism. The top plate of the deck is supported by 4 springs to isolate it from the plinth which is chipboard with a veneer to make it look like real wood. The plinth is a little less substantial than the pioneer one, shallower and with a hardboard panel on the lower side.

The motor is supported  by 3 rubber bushes on 3 rods, exactly the same as the PL12. The motor ran silently from the start. Its not clear where oil is to be applied, but you can see that the lower bearing appears to be accessible easily without having to dismantle the entire motor. Another nice feature of the JVC is that the motor is also supported by two loose bolts which pass through the top plate. These allow you to remove the 3  suspension bolts to service the rubber bushes, without having to hold the motor. They allow it to safely hang, but in normal use they do not have any contact with the top plate.

As with the Pioneer I removed the 3 rubber bushes and along with the belt and rubber mat they had the same process. Clean in warm soapy water, dry and treat with Platanclene roller restorer in a plastic bag for an hour.

The main bearing was very stiff. The whole bearing assembly can easily be removed, its held in place by 3 screws through the top plate. Once removed I could see it uses the same side screw to hold the spindle in place. I removed the screw and carefully extracted the spindle. A few taps elicited the ball bearing that sat at the bottom of the bearing well. All were sticky with old hardened grease so I washed all parts in warm soapy water , dried and further cleaned with Servisol 10 contact cleaner. The JVC bearing well is not brass but some alloy, with what looks like different material for the base possibly Delrin. Once I had cleaned the well with cotton buds and  the spindle and bearing, I reassembled adding a blob of Moly grease to the spindle. Now spins smoothly and effortlessly.

As you can see from the picture of the motor , the springs didn't have foam cores to act as shock absorbers. . However around the top edge of the wooden plinth were blocks of foam rubber which I presume served the same purpose, and as with the PL12 were perished. The top plate is held in place by 3 catches which you disengage from the top via 3 screws, similar again to the PL12.  You can lift the top plate as before but there is not much slack from the white mains cable which passes out of the plinth through a metal plate with a compression collar. Removing this was the hardest part of the whole process, but it enabled me to gain full access to the deck.


I found some foam rubber and added some cores to the springs a la PL12. I replaced the grounding wire as the original had been cut and re-joined from some older wire. I fitted a length of wire and used a couple of soldered eyelets at each end.

Reassembling the deck was easy. I applied power and the motor was absolutely silent in operation. Checking the speed with a strobe disk indicated no problems, it kept good pitch at 33 and 45 and the speed selector worked well. The JVC mounts the selector arm in a nylon sleeve which is a nice refinement as the PL12 arm is inclined to rattle.

I tested the return mechnism and  while it did return the arm to its holder, there was a clicking sound at the end. The gears on the top were not quite disengaging from each other . I lubricated all of the pivot poitns in the cogs aboe and , underneath again I applied small drops of oil to the  pivots for the various arms. The black plastic sliding rod you can see in the lower right of the picture has a captive rolling ball bearing between it and the white nylon housing it extends into . This was a bit sticky and I applied a drop of oil here and worked the bearing in and out till it seemed effortless.

Reassembly and the whole automatic mechanism worked fine, no clicking this time.

I finally tried playing a record. The deck had come with its original headshell fitted with an Ortofon FF15 cartridge. I've another deck with one of these and it's an excellent model. I always fit a new stylus, so ordered a replacement from William Thakker in Germany, who are very good. I choose one of their OEM stylus for around €27. In the meantime I tried the Pioneer headshell with the Shure M75, and it sounded quite good. It was a little noisier, some background hum, but not too bad.

The stylus came and I decided to use a different headshell initially, as , while the JVC original looked good, it was quite flimsy and had some hardened damping material stuck inside. Interestingly using a generic and very good headshell (£6 from ebay) I got no music from the left channel. After a bit of experimenting, it appeared to be a poor connection inside the headshell collar, and removing the rubber washer from the plug half of the headshell sorted the connection. The deck was also noticeably quieter, my hum had gone. With the generic headshell and the FF15 with OEM , it does sound very good indeed. is it better than the PL12 ? hard to say, It has many of the same qualities and perhaps the motor is a little better. I think the pitch on the PL12 is not as good as the JVC, but that could be the motor is more worn. certainly the JVC Motor is more modern looking. The JVC has a tiny amount of in/out play in horizontal arm bearing, but the various arms and levers inside the deck for the auto mechanism mean that the two locking nuts are inaccessible. I think I may live with that.


10 comments:

Anonymous said...

I've just bought one of these. Your tips, I'm sure, will be very useful. Thank you.

Merilyn Anvelt said...

Hello,

I have the same turntable but I have few problems and I thought maybe you could help.
Mine is also automatic but the problem is that always when the lp ends the arm goes back but it won't stay there, only a moment and then it goes back and lands on the middle of the lp with bad noise. Why is it doing so? Is it possible to make it stop doing it?
Sometimes the arm decides to do the same thing not when the lp ends but when it is in the middle. But if I understood right the last thing may be because of the wrong anti skating and the weight? What anti skating and weight did you put on your turntable?
Really hope you could help me.

Best Wishes,
Merilyn

Mr Ives said...

Hi Merilyn,

I would suspect that the grease in the automatic mechanism has become sticky with age and the system of gears and rodes which take the arm back at the end of the side (or by pressing the reset button) is not working as it should.

One of my pictures shows the deck from above with the platter removed. This shows the central spindle which has a geared collar. The spindle can turn freely becuase the larger gear to one side has a notch of missing teeth. I believe that this is not working quite right. The lubrication on that larger wheel is probably preventing it from presenting the missing section to the smaller gear, which should be its default state. You can sort of simulate the whole provess by manually moving the arm across and watching how the bigger wheel finally gets moved into engagement with the smaller gear. Its easy to understand when watching but harder to explain.

I think you probably need to lubricate the central axle of the large wheel with a few drops of oil, best is sewing machine oil which is thin. Then work the mechanism to get the oil into the coupling. This might be enough. However there are a few rods and wheels inside which can only be accessed from beneath. Only try this with the power unplugged at the mains BTW.

Basically a few drops of oil in a relatively few places should sort this out.

the other approach is to remove the whole auto mechanism and turn the deck into a manual. This is poossible but quite fiddly and you will have the issue how to turn the deck on and off, which currently a rod beneath does when the arm moves across.

I think a bit of oil and TLC on a deck , which, after all is best part of 35 years old, should get you working again

I dont think your problem is connected with anti skate or the balance weight. On mine these are both set to 1.5grams which is correct for the Shure M75 cartridge I use. be aware that the balance weight i.e the larger weight has to be balanced and then set the smaller black ring to zero, then rotate both till you get the right weight.

Anonymous said...

Hi. I'm having trouble with my jvc too. I hope you could help. The auto return doesn't work. It works fine when you reject but won't return at the end of the record. The table has been stripped, cleaned and lubed. The issue is, I think is the long black plastic arm that should push the metal tab that engages the return mechanism. Should it run captive in the white nylon runner? Mine just flops about in the runner. and it's not hitting the return mech accurately enough. I've had to repair the lever that clamps to the tone arm pivot so was wondering if this was another reason the table was binned in the first place?

Mr Ives said...

Hi, sorry for the delay, i seemed to have a few coments regarding the blog that i didnt notice the email notifications for.

The black rod is held captive in the white nylon piece, but there is a ball bearing sandwiched between the two pieces that allows smooth running. Do you have this ?

Have a looke here http://4.bp.blogspot.com/-dJ3CmjgV45k/UuTdY_2KnmI/AAAAAAAACIo/ZoTLbobX49U/s1600/IMG_1036.JPG

You can just see the silver bearing inside the white box shaped holder that has the black rod running through it

I gave the JVC to a good friend as a special 50th birthday present , so i cant tale a look at mine.

The other thing it could be is if you look at that picture you will see further toward the back of the deck is a metal piece, gold or brass in colour that is hooked , it pivots and carries a white nylon arm which touches the micro switch. If you look at the hooked end i.enthe end furthest from the micro switch, you will see there is a pad of rubber. This makes contact with the arm raise mechnaism. Sometimes the foam rubber pad perishes with age and needs to be replaced or the arm doesnt raise properly. Hope this helps , sorry for the slow reply

Sometimes you just have to remove the platter,balance the deck on its back, remove the bottom, and simulate the movement of the arm while watching which mechanisms it engages with beneath

Max Webster said...

hi really hope you get this message ive jut bought one of these and cant seem to get the turntale moving the metal rod sticking through the top spins but when i replace the metal disc that the record sits on it doesnt spin and nothing touches

Mr Ives said...

Hi Max , just got home and also saw what i think was your post on vinyl engine. I think you just need a belt which has to hoop around the underside ring of the platter and around the brass spindle. If the previous owner said it worked id expect the old belt to be maybe around the platter or in the box ? No matter but when you find the belt, which is like a large. Dark grey rubber band, you just hoop it around the rim of the ring on the underside of the platter, then drop the platter back on, then via the two access holes in the platter, loop the belt over the motor spindle

Anonymous said...

hi, i just purchased an used jvc jl a1, but the weight at the end of the arm is missing. is there any chance you can tell me the weight of this piece, so i could get someone to make one for me? thanks in advance!

Mr Ives said...

Hi Anonymous

Sorry I can't tell you exactly as I gave the deck to a good friend as a 50th birthday present.

Many Japanese decks share similar components and you may find the balance weight from a similar vintage deck from other brands fits on to your decks arm stub. They screw on using a gentle internal spiral with a ball race. The weight needs to be able to balance whatever cartridge you choose , then allow movement to apply the tracking force. While there is a calibrated ring on the front, they are only needed if you don’t have cartridge scales.

Anonymous said...

thx a whole lot for the quick reply and the whole article, which is extremely helpful.