Jake 4,031 Posted September 19, 2013 Share Posted September 19, 2013 I thought the bearing was "not part of the problem". How can one be confident of success yet? Did I miss something? Still reckon the motor is dodgy myself. Yes, I think you "missed something", Jake! Stuart fixed the "motor problem". The drive IC still ran away and the speed increased. He posted that he could get this effect to happen, simply by heating up the IC with a hair dryer. That says to me that something was causing the drive IC to work overtime, so it got hot. It makes sense to me that bearing friction could have caused this - the speed was slowing ... so the drive IC was working overtime to increase speed ... so it got hot. Remove the friction ... and the drive IC doesn't have to get hot ... so the speed remains constant. Why the friction - it would seem old, dirty oil? Regards, Andy Yes, I read all that. But initial inspection of bearing showed no problem. But fault cannot be replicated now, so despite bearing being ok, everyone celebrating. Still think I missed something. Link to post Share on other sites
andyr 5,749 Posted September 19, 2013 Share Posted September 19, 2013 (edited) Yes, I read all that. But initial inspection of bearing showed no problem. But fault cannot be replicated now, so despite bearing being ok, everyone celebrating. Still think I missed something. As you say, initial inspection of the mechanical wear on the bearing showed no problem. But I could imagine that dirty oil would have a negative effect - hindering the smooth rotation and so causing the drive IC to have to work harder. Regards, Andy Edited September 19, 2013 by andyr Link to post Share on other sites
Jake 4,031 Posted September 19, 2013 Share Posted September 19, 2013 Yes, I read all that. But initial inspection of bearing showed no problem. But fault cannot be replicated now, so despite bearing being ok, everyone celebrating. Still think I missed something. As you say, initial inspection of the mechanical wear on the bearing showed no problem. But I could imagine that dirty oil would have a negative effect - hindering the smooth rotation and so causing the drive IC to have to work harder. Regards, Andy Well, that must be some intolerant IC then. Link to post Share on other sites
Once Analog 153 Posted September 19, 2013 Share Posted September 19, 2013 (edited) Some thoughts on turntable speed control. Turntables driven by a DC motor usually incorporate a closed loop feedback control system. The design parameters of the controller allow for a range of variables within the motor, pulley, belt, platter and bearing system. If any of these variables e.g. bearing friction, exceeds the expected parameters then the control system may not be able to maintain stability and may even enter a chaotic state. The extent and period of the random variations depends on the type and gain of the feedback. Bearing friction is not an obvious or intuitive cause of erratic speed but should always be considered in diagnosing problems. Removing all traces of old, contaminated lubricants, thoroughly cleaning bearing surfaces and replacing the lubricants with high quality products can work miracles with your turntable speed control and improve the sound as a bonus. Best to all, Vince Edited September 19, 2013 by Once Analog Link to post Share on other sites
Telecine 3,914 Posted September 19, 2013 Share Posted September 19, 2013 Great work so far Vince but I an sticking with my theory which means that you still will have an electronic issue to deal with ; ) Link to post Share on other sites
Once Analog 153 Posted September 20, 2013 Share Posted September 20, 2013 24 hours pass, (continuous running), both speeds stable, no fluctuation! Vince Link to post Share on other sites
lovetube 657 Posted September 20, 2013 Share Posted September 20, 2013 24 hours pass, (continuous running), both speeds stable, no fluctuation! Vince i think you nailed it Vince Duc Link to post Share on other sites
Once Analog 153 Posted September 20, 2013 Share Posted September 20, 2013 i think you nailed it Vince Duc Hi Duc, Maybe, 36 hours now and speeds still stable, will continue to monitor. Vince Link to post Share on other sites
lovetube 657 Posted September 20, 2013 Share Posted September 20, 2013 Hi Duc, Maybe, 36 hours now and speeds still stable, will continue to monitor. Vince Hi Vince . i would call it a success mission .actually i'm very surprise the problem was caused y the bearing. i never have thought the bearing cause speed problem. i only recommend clean/checking the bearing for the sake of it but never hope it will solve the problem , i suppose we live and learn cheers Duc Link to post Share on other sites
Addicted to music 7,112 Posted September 20, 2013 Share Posted September 20, 2013 Hi Vince, can you name the lubricant you used please! Link to post Share on other sites
Once Analog 153 Posted September 20, 2013 Share Posted September 20, 2013 Hi Vince, can you name the lubricant you used please! Certainly; it's "FINISH LINE" available from bicycle shops. Vince Link to post Share on other sites
Once Analog 153 Posted September 21, 2013 Share Posted September 21, 2013 (edited) 58 hours pass, Luxman speeds still stable, hmm. Not ruling out some intermittent problem that hasen't surfaced? Like UM said, this Luxman has tricked others! I think we can say the motor is not an issue. Vince Edited September 21, 2013 by Once Analog Link to post Share on other sites
Addicted to music 7,112 Posted September 21, 2013 Share Posted September 21, 2013 Certainly; it's "FINISH LINE" available from bicycle shops. Vince Is it this stuff; http://www.finishlineusa.com/products/cross-country-lube.htm Link to post Share on other sites
Once Analog 153 Posted September 21, 2013 Share Posted September 21, 2013 Is it this stuff; http://www.finishlineusa.com/products/cross-country-lube.htm That's the "Brand", the grease is the one they refer to as "Premium Grease". It's available in a tube or tub, expensive. Vince Link to post Share on other sites
Addicted to music 7,112 Posted September 21, 2013 Share Posted September 21, 2013 That's the "Brand", the grease is the one they refer to as "Premium Grease". It's available in a tube or tub, expensive. Vince This one: http://www.finishlineusa.com/downloads/pdf/Teflon_Grease_Info_Sheet.pdf Link to post Share on other sites
Once Analog 153 Posted September 21, 2013 Share Posted September 21, 2013 This one: http://www.finishlineusa.com/downloads/pdf/Teflon_Grease_Info_Sheet.pdf You got it, that's it! 1 Link to post Share on other sites
Addicted to music 7,112 Posted September 21, 2013 Share Posted September 21, 2013 I use this a product similar to this at work: http://www.finishlineusa.com/downloads/pdf/Extreme_Fluoro_Info_Sheet.pdf for temp higher than 180 degree C we use this: http://www.klueber.com/en/product-detail/id/350/ Link to post Share on other sites
Addicted to music 7,112 Posted September 21, 2013 Share Posted September 21, 2013 You got it, that's it! Cool! Link to post Share on other sites
Once Analog 153 Posted September 21, 2013 Share Posted September 21, 2013 Luxman Bearing Service Difficult The Luxman bearing is held in place with a 55mm Hex nut and someone had used "Loc Tite" on the thread! I lost 2 hours removing the bearing housing. How was it done? I removed the platter support bracket and submerged the nut in a saucepan of boiling water. The oil was the worst condition I have ever seen! Vince Link to post Share on other sites
unclemack 3,299 Posted September 21, 2013 Author Share Posted September 21, 2013 Another shot of the beauty courtesy of Vince. Cheers M 1 Link to post Share on other sites
Addicted to music 7,112 Posted September 21, 2013 Share Posted September 21, 2013 Luxman Bearing Service Difficult The Luxman bearing is held in place with a 55mm Hex nut and someone had used "Loc Tite" on the thread! I lost 2 hours removing the bearing housing. How was it done? I removed the platter support bracket and submerged the nut in a saucepan of boiling water. The oil was the worst condition I have ever seen! Vince Would this have been done during manufacturing? Link to post Share on other sites
Once Analog 153 Posted September 21, 2013 Share Posted September 21, 2013 Would this have been done during manufacturing? Doubt it, Luxman wouldn't be that silly! Vince Link to post Share on other sites
Once Analog 153 Posted September 22, 2013 Share Posted September 22, 2013 The drive IC still ran away and the speed increased. He posted that he could get this effect to happen, simply by heating up the IC with a hair dryer. Regards, Andy Quite common Andy. After applying the hair dryer trick to heat up the IC, giving the motor erratic behaviour, it should have been followed up with swabbing the IC with methylated spirits which would pull the heat from the IC very effectively. Monitoring the motor speed. Repeated several times would have given the IC pattern? If constant, would have shown the IC is sensitive to temperature change and show the IC had a problem, even though changed. My next test. Vince Link to post Share on other sites
Once Analog 153 Posted September 22, 2013 Share Posted September 22, 2013 (edited) Also Noted: I have been running the Luxman, (trouble free) without the bottom cover. Underneath the Luxman is a confined area, the metal sealed cover, with the exception of the phono cable hole, (back right hand corner) has NO vented holes, especially above the cct board - do we have an oven here effecting the IC? Vince Edited September 22, 2013 by Once Analog 1 Link to post Share on other sites
Addicted to music 7,112 Posted September 22, 2013 Share Posted September 22, 2013 There's only on e way to tell, keep in mind that the Luxman has been this way new out of the box, new, it hasnt had a problem until now! Link to post Share on other sites
unclemack 3,299 Posted September 22, 2013 Author Share Posted September 22, 2013 There's only on e way to tell, keep in mind that the Luxman has been this way new out of the box, new, it hasnt had a problem until now!t Yes, you would think that an oven effect would point to a design flaw which very quickly would have been discovered and well documented. Still, this TT has done things most other TTs have not! Cheers M Link to post Share on other sites
Once Analog 153 Posted September 23, 2013 Share Posted September 23, 2013 Regardless, it won't hurt to drill some ventilation holes in the base plate, especially above the cct. Vince 1 Link to post Share on other sites
Once Analog 153 Posted September 25, 2013 Share Posted September 25, 2013 (edited) Hi UM, Some further progress, heat was applied to the motor without any affect, (no change in motor RPM),I think the motor is ok. Applied heat to the ICs and a different story, motor speeded up, but swabbing with Metho reduced the motor (RPM. Sensitive to temperature change). Set the potentiometer presets, so now the exact speeds are correct, in the centre of adjustment. Also, the belt supplied is it an original "Luxman"? The platter/motor/pulley and drive belt are a designed system, not individual components. Vince Edited September 25, 2013 by Once Analog Link to post Share on other sites
unclemack 3,299 Posted September 25, 2013 Author Share Posted September 25, 2013 Thanks Vince, Not sure whether the belt is an original or not... Is there any way to tell? Cheers M Link to post Share on other sites
Saxon Hall 4,214 Posted September 25, 2013 Share Posted September 25, 2013 Luxman Bearing Service Difficult The Luxman bearing is held in place with a 55mm Hex nut and someone had used "Loc Tite" on the thread! I lost 2 hours removing the bearing housing. How was it done? I removed the platter support bracket and submerged the nut in a saucepan of boiling water. The oil was the worst condition I have ever seen! Vince I hate that Loc-Tite muck. More trouble than what it is worth IMO. I have it at my work and I only use it only sparingly and reluctantly! Link to post Share on other sites
djb 3,196 Posted September 25, 2013 Share Posted September 25, 2013 "is there a TT bearing expert in Melbourne?" I suspect the reason your getting few responses to your exact question is- would I offer the name of a skilled technician to solve this problem? I could well become their worst enemy over night. 10 -20 house hundreds of dollars and no result I notice the couple of experts who frequent this site from Melbourne are keeping their collective heads down Link to post Share on other sites
djb 3,196 Posted September 25, 2013 Share Posted September 25, 2013 "is there a TT bearing expert in Melbourne?" I suspect the reason your getting few responses to your exact question is- would I offer the name of a skilled technician to solve this problem? I could well become their worst enemy over night. 10 -20 hours hundreds of dollars and a strong possibility of no result I notice the couple of experts who frequent this site from Melbourne are keeping their collective heads down No not a reference to Zaph who weall know has 2 heads- he lives in NSW Link to post Share on other sites
Addicted to music 7,112 Posted September 25, 2013 Share Posted September 25, 2013 I hate that Loc-Tite muck. More trouble than what it is worth IMO. I have it at my work and I only use it only sparingly and reluctantly! Its how when and where you use it! There are also different types and strengths. Use it the wrong way and you have Vince on your back! Link to post Share on other sites
soundfan 9,077 Posted September 25, 2013 Share Posted September 25, 2013 Hi UM, Some further progress, heat was applied to the motor without any affect, (no change in motor RPM),I think the motor is ok. Applied heat to the ICs and a different story, motor speeded up, but swabbing with Metho reduced the motor (RPM. Sensitive to temperature change). Set the potentiometer presets, so now the exact speeds are correct, in the centre of adjustment. Also, the belt supplied is it an original "Luxman"? The platter/motor/pulley and drive belt are a designed system, not individual components. Vince In regards to your last sentence Vince, I'm not sure that it matters too much in regards to the drive belt. I replaced the original belt on the PD350 I owned, with an after market belt.....and it was fine for the remaining 4 or 5 yrs I had the table. Link to post Share on other sites
samman 277 Posted September 25, 2013 Share Posted September 25, 2013 Another shot of the beauty courtesy of Vince. Cheers MBeautiful looking T/T.... UM Link to post Share on other sites
Once Analog 153 Posted September 25, 2013 Share Posted September 25, 2013 Beautiful looking T/T.... UM Yes Sam, it's a beauty! A turntable that has.been built to a standard, not a price, no compromises! Vince 1 Link to post Share on other sites
Once Analog 153 Posted September 26, 2013 Share Posted September 26, 2013 Luxman, Platter Rotational Accuracy: Using a "Mitutoyo" Dial Indicater, the following measurements were made: Axial Runout: .004", Runout On Diameter: .002", Spindle: .001" Compared the above with the OA: Axial Runout: .003", Runout On Diameter: .001",Spindle Runout: .002". In my view both perfect! Vince Link to post Share on other sites
Once Analog 153 Posted September 26, 2013 Share Posted September 26, 2013 In regards to your last sentence Vince, I'm not sure that it matters too much in regards to the drive belt. I replaced the original belt on the PD350 I owned, with an after market belt.....and it was fine for the remaining 4 or 5 yrs I had the table. In a belt driven turntable, belt dimensions are the utmost importance; length, width and thickness (elasticity) are crucial in determining a given turntable's problem. Without the original belt, designed by the maker, any diagnosis is pointless! Example: if the belt is too short it will increase speed and bearing wear, (side way force). If too long, will slip and speed will be slow. The correct belt length should be a loose fit without slipping. A "Soundfan" should know this! Vince Link to post Share on other sites
soundfan 9,077 Posted September 26, 2013 Share Posted September 26, 2013 In regards to your last sentence Vince, I'm not sure that it matters too much in regards to the drive belt. I replaced the original belt on the PD350 I owned, with an after market belt.....and it was fine for the remaining 4 or 5 yrs I had the table. In a belt driven turntable, belt dimensions are the utmost importance; length, width and thickness (elasticity) are crucial in determining a given turntable's problem. Without the original belt, designed by the maker, any diagnosis is pointless! Example: if the belt is too short it will increase speed and bearing wear, (side way force). If too long, will slip and speed will be slow. The correct belt length should be a loose fit without slipping. A "Soundfan" should know this! Vince Lets be realistic here Vince. You will not find an original belt anymore for this table. The aftermarket belt I ended up buying worked a treat, so I take some of your comments with a grain of salt. And no..... I didn't just buy any belt and hope for the best, the belt I purchased was meant for use with the PD350. Give me some credit before lecturing me.....I did own this very table for nearly a decade. 1 Link to post Share on other sites
samman 277 Posted September 26, 2013 Share Posted September 26, 2013 Lets be realistic here Vince. You will not find an original belt anymore for this table. The aftermarket belt I ended up buying worked a treat, so I take some of your comments with a grain of salt. And no..... I didn't just buy any belt and hope for the best, the belt I purchased was meant for use with the PD350. Give me some credit before lecturing me.....I did own this very table for nearly a decade. Don't think it was meant to be a personal attack on you personally....Soundfan... Link to post Share on other sites
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