Help! Technics SL3 problems. - UK Vintage Radio Repair and Restoration Discussion Forum

thomash93 · 16th Mar 2018, 5:34 pm

Hi

I recently dusted off my dad's old Technics SL3 and replaced the turntable belt. It worked fine considering it hadn't been used for about 20 years, felt very smug with my repair skills.

However after a few uses it's now started to power down (the light in the power on button fades), stops playing and the needle arm moves back to the side. At first it started doing this halfway through a LP, now it often does it as soon as the needle hits the record.

Any ideas?

Audio1950 · 16th Mar 2018, 11:13 pm

It sounds as though the trip mechanism is sticking, possibly with old hardened grease. I don't know this particular deck, but if you could post a picture of the centre of the deck with the turntable removed, we can see the trip mechanism and advise accordingly.

Michael Maurice · 16th Mar 2018, 11:38 pm

Its a linear tracking turntable, no trip mechanism on these.

Lloyd 1985 · 17th Mar 2018, 1:19 am

This is a similar looking machine to the SL-5, which I have a pair of. Does the SL-3 use a figure 8 power lead? My SL-5 does, and I had a dodgy lead that wasn’t contacting correctly which made it do some funny things once, replacing it cured the problem, so might be worth trying. This does sound like a power issue caused by a loose connection somewhere, as when you disconnect power to one of these in the middle of playback, when power is restored it will reset, moving the arm back to its resting point.

If the mains cable is a permanently attached one then it could be a loose connection in the plug, if it’s not a moulded one.

Regards
Lloyd

Diabolical Artificer · 17th Mar 2018, 7:05 am

Welcome to the forum. How comfortable are you with working with electrics? this fault is probably just a matter of wiggling things like the the figure of eight cable connector Lloyd mentioned til you trace the fault. It could also be a micro switch or just loose wiring somewhere.

Start at the plug as recommended and work your way forward.

Andy.

Marconi_MPT4 · 17th Mar 2018, 12:43 pm

Hi,

Most Technics linear track turntables have a small motor in the lid to drive the arm mechanism via a small rubber belt. These belts often go slack and if the arm mechanism does not move across or is sluggish in operation, a large tracking error is produced. This error threshold is monitored by the micropocessor and will stop play to protect both stylus and record.

Apart from the belt requiring replacement, there is also grease lubricating the arm sled mechanism which should be checked. Drive cord must not slack.

If the power-on LED fades, after checking the advice already given in the thread there are two other possibilities. Dry joints (usually) on the power regulator, usually a LM7812/15 etc, or the reservoir capacitor has dried up resulting in poor regulation. Second possibility is excessive supply loading causd by one of the motor drives drawing too much current.

Cheers
Rich

'LIVEWIRE?' · 17th Mar 2018, 2:16 pm

In addition to what you mention, Rich, The brass pulley on which that small belt runs can come off its shaft, with the same results. The pulley is basically a press fit onto the motor shaft, and is 'secured' with a Loctite type compound. For almost a year now, I've had a SL-7 among my 'to-do' jobs, and haven't been able to solve this problem. There's a thread on here somewhere about that.

thomash93 · 17th Apr 2018, 3:53 pm

Many thanks to everyone who took time to respond. Update as follows -

After finding a new power cord I determined that wasn't the problem as it made no difference.

So I took the top cover off to check the mechanism. The arm sled had some grease on it and I smeared on a little extra that I found dabbed on the inside of the case.

I then opened up the base to look for dry joints, nothing appeared amiss to my untrained eye but I gather these can things can be difficult to spot.

I reassembled the base at which point the power button started to power off as soon as I turned it on. I fiddled around with it, held it down firmly for a couple of seconds and suddenly the problem went away, very odd.

To test the arm mechanism I tried running the player with a disc while the cover was still off the arm mechanism. This seems to be a major improvement, it hasn't turned itself off once even after 6 or so full play throughs and the power light is fully on. I was surprised to find the motor that powers the arm mechanism doesn't seem to run continuously but instead seems to come on about once a second, everything seems to work okay at this point so assume this is correct?

However I did notice the band that drives the arm mechanism does appear slightly slack and at one point as I was running it without a disc the drive belt stopped turning and needed a nudge to get it going.

As per the suggestions here I suspect at least part of my problem was the slack drive belt on the arm mechanism, smearing a little extra grease has probably helped for now but I think it best to replace the belt before putting everything back together.

Would someone be able to advise where I can find a suitable belt? Also if a little extra grease wouldn't hurt what type I should use?

Thanks again for all the suggestions and advice.

Tractorfan · 18th Apr 2018, 10:27 am

Hi,
As the stylus tracks across the record an error massage is produced which causes the motor to run and advance the arm until the error clears. The stylus continues to track and another error message appears, and so the cycle repeats. Therefore, the motor running in little 'spurts' is normal. (Incidentally, the same thing happens with CD & DVD players.)
Don't put even more grease on where there was only a little bit before, as this can 'gunge' up the mechanism and make life harder for the tracking motor. Better to remove the old grease in case it's hardened over the years and apply fresh grease.
Hope this helps.
Cheers, Pete.

thomash93 · 8th May 2018, 12:28 pm

I recently opened the casing that holds the tone arm and motor (arm case?) on my Technics SL-3 to check the tone arm mechanism and subsequently replaced the tone arm mechanism belt.

After several attempts to remember how I took it apart I managed to carefully put everything back together. However I've now discovered the tone arm won't drop.

Turning on the power and pressing start the platter begins to spin and a whirring noise comes from the arm casing as if the tone arm is moving to the edge of the record, there is then a click and at this point the arm used to drop. However now the arm does nothing and the motor continues to whirr away.

Fearing this is damaging the mechanism I turned the power off, took apart the arm case and tried the mechanism with the lid off. Worked fine. So I reassembled the case. Same thing as before, the arm won't drop. Tried dissembling and assembling a few times thinking I was somehow catching the arm on the casing and this was stopping it from moving.

No such luck, I can't see how the arm can be caught on the case and I can't for the life of me work out what I'm doing wrong.

Does anyone have any idea what I've done wrong as this is driving me mad!

16th Mar 2018, 5:34 pm	#1
thomash93 Retired Dormant Member Join Date: Mar 2018 Location: London, UK. Posts: 5	Help! Technics SL3 problems. Hi I recently dusted off my dad's old Technics SL3 and replaced the turntable belt. It worked fine considering it hadn't been used for about 20 years, felt very smug with my repair skills. However after a few uses it's now started to power down (the light in the power on button fades), stops playing and the needle arm moves back to the side. At first it started doing this halfway through a LP, now it often does it as soon as the needle hits the record. Any ideas?

16th Mar 2018, 11:13 pm	#2
Audio1950 Dekatron Join Date: Nov 2008 Location: Whittlesey, near Peterborough, Cambridgeshire, UK. Posts: 3,761	Re: Help! My Technics SL3 keeps turning itself off It sounds as though the trip mechanism is sticking, possibly with old hardened grease. I don't know this particular deck, but if you could post a picture of the centre of the deck with the turntable removed, we can see the trip mechanism and advise accordingly.

16th Mar 2018, 11:38 pm	#3
Michael Maurice Moderator Join Date: Feb 2006 Location: Wembley, Middlesex Posts: 7,222	Re: Help! My Technics SL3 keeps turning itself off Its a linear tracking turntable, no trip mechanism on these. __________________ Forum Moderator http://www.michaelmauricerepairs.co.uk/

17th Mar 2018, 1:19 am	#4
Lloyd 1985 Nonode Join Date: Jun 2008 Location: Coningsby, Lincolnshire, UK. Posts: 2,818	Re: Help! My Technics SL3 keeps turning itself off This is a similar looking machine to the SL-5, which I have a pair of. Does the SL-3 use a figure 8 power lead? My SL-5 does, and I had a dodgy lead that wasn’t contacting correctly which made it do some funny things once, replacing it cured the problem, so might be worth trying. This does sound like a power issue caused by a loose connection somewhere, as when you disconnect power to one of these in the middle of playback, when power is restored it will reset, moving the arm back to its resting point. If the mains cable is a permanently attached one then it could be a loose connection in the plug, if it’s not a moulded one. Regards Lloyd

17th Mar 2018, 7:05 am	#5
Diabolical Artificer Dekatron Join Date: Jul 2009 Location: Sleaford, Lincs. UK. Posts: 7,657	Re: Help! My Technics SL3 keeps turning itself off Welcome to the forum. How comfortable are you with working with electrics? this fault is probably just a matter of wiggling things like the the figure of eight cable connector Lloyd mentioned til you trace the fault. It could also be a micro switch or just loose wiring somewhere. Start at the plug as recommended and work your way forward. Andy. __________________ Curiosity hasn't killed this cat...so far.

17th Mar 2018, 12:43 pm	#6
Marconi_MPT4 Heptode Join Date: Mar 2011 Location: Dorset, UK. Posts: 521	Re: Help! My Technics SL3 keeps turning itself off Hi, Most Technics linear track turntables have a small motor in the lid to drive the arm mechanism via a small rubber belt. These belts often go slack and if the arm mechanism does not move across or is sluggish in operation, a large tracking error is produced. This error threshold is monitored by the micropocessor and will stop play to protect both stylus and record. Apart from the belt requiring replacement, there is also grease lubricating the arm sled mechanism which should be checked. Drive cord must not slack. If the power-on LED fades, after checking the advice already given in the thread there are two other possibilities. Dry joints (usually) on the power regulator, usually a LM7812/15 etc, or the reservoir capacitor has dried up resulting in poor regulation. Second possibility is excessive supply loading causd by one of the motor drives drawing too much current. Cheers Rich __________________ To an optimist a glass is half full; a pessimist half empty; an engineer twice as big as need be!

17th Mar 2018, 2:16 pm	#7
'LIVEWIRE?' Rest in Peace Join Date: Mar 2006 Location: N.W. Oxfordshire(Chipping Norton) Posts: 7,306	Re: Help! My Technics SL3 keeps turning itself off In addition to what you mention, Rich, The brass pulley on which that small belt runs can come off its shaft, with the same results. The pulley is basically a press fit onto the motor shaft, and is 'secured' with a Loctite type compound. For almost a year now, I've had a SL-7 among my 'to-do' jobs, and haven't been able to solve this problem. There's a thread on here somewhere about that.

17th Apr 2018, 3:53 pm	#8
thomash93 Retired Dormant Member Join Date: Mar 2018 Location: London, UK. Posts: 5	Re: Help! My Technics SL3 keeps turning itself off Many thanks to everyone who took time to respond. Update as follows - After finding a new power cord I determined that wasn't the problem as it made no difference. So I took the top cover off to check the mechanism. The arm sled had some grease on it and I smeared on a little extra that I found dabbed on the inside of the case. I then opened up the base to look for dry joints, nothing appeared amiss to my untrained eye but I gather these can things can be difficult to spot. I reassembled the base at which point the power button started to power off as soon as I turned it on. I fiddled around with it, held it down firmly for a couple of seconds and suddenly the problem went away, very odd. To test the arm mechanism I tried running the player with a disc while the cover was still off the arm mechanism. This seems to be a major improvement, it hasn't turned itself off once even after 6 or so full play throughs and the power light is fully on. I was surprised to find the motor that powers the arm mechanism doesn't seem to run continuously but instead seems to come on about once a second, everything seems to work okay at this point so assume this is correct? However I did notice the band that drives the arm mechanism does appear slightly slack and at one point as I was running it without a disc the drive belt stopped turning and needed a nudge to get it going. As per the suggestions here I suspect at least part of my problem was the slack drive belt on the arm mechanism, smearing a little extra grease has probably helped for now but I think it best to replace the belt before putting everything back together. Would someone be able to advise where I can find a suitable belt? Also if a little extra grease wouldn't hurt what type I should use? Thanks again for all the suggestions and advice.

18th Apr 2018, 10:27 am	#9
Tractorfan Dekatron Join Date: Mar 2008 Location: St. Frajou, l'Isle en Dodon, Haute Garonne, France.(Previously: Ellesmere Port, Cheshire, UK.) Posts: 3,182	Re: Help! My Technics SL3 keeps turning itself off Hi, As the stylus tracks across the record an error massage is produced which causes the motor to run and advance the arm until the error clears. The stylus continues to track and another error message appears, and so the cycle repeats. Therefore, the motor running in little 'spurts' is normal. (Incidentally, the same thing happens with CD & DVD players.) Don't put even more grease on where there was only a little bit before, as this can 'gunge' up the mechanism and make life harder for the tracking motor. Better to remove the old grease in case it's hardened over the years and apply fresh grease. Hope this helps. Cheers, Pete. __________________ "Hello?, Yes, I'm on the train, I might lose the signal soon as we're just going into a tunn..."

8th May 2018, 12:28 pm	#10
thomash93 Retired Dormant Member Join Date: Mar 2018 Location: London, UK. Posts: 5	Tone arm won't drop - Technics SL-3 I recently opened the casing that holds the tone arm and motor (arm case?) on my Technics SL-3 to check the tone arm mechanism and subsequently replaced the tone arm mechanism belt. After several attempts to remember how I took it apart I managed to carefully put everything back together. However I've now discovered the tone arm won't drop. Turning on the power and pressing start the platter begins to spin and a whirring noise comes from the arm casing as if the tone arm is moving to the edge of the record, there is then a click and at this point the arm used to drop. However now the arm does nothing and the motor continues to whirr away. Fearing this is damaging the mechanism I turned the power off, took apart the arm case and tried the mechanism with the lid off. Worked fine. So I reassembled the case. Same thing as before, the arm won't drop. Tried dissembling and assembling a few times thinking I was somehow catching the arm on the casing and this was stopping it from moving. No such luck, I can't see how the arm can be caught on the case and I can't for the life of me work out what I'm doing wrong. Does anyone have any idea what I've done wrong as this is driving me mad!