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unclemack

Is there a TT bearing expert in Vic? the Luxman beckons..

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"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

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"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

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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!

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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.

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ve9eheba.jpg Another shot of the beauty courtesy of Vince. Cheers M

Beautiful looking T/T.... UM

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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

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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

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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

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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.

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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...

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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.

Hi,

Wasen't meaning to be personal, apology.

Vince

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azaruje2.jpg getting the FR54 ready to send to Vince for fitting and final testing. Getting antsy now.

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Guest Muon

Mmmm........shiny :love

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It is a little shiny but that's mostly the Challengers armboard. I have to find a better looking headshell to complete the look. Cheers. M

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azaruje2.jpg getting the FR54 ready to send to Vince for fitting and final testing. Getting antsy now.

UM,

The FR54 will be up and singing soon enough!

Vince

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Luxman PD-350 Turntable:

Fault Description: Intermittent uncontrolled speed increase without recovery (power needs to be cycled).

Supplied service manual provided no real help except for a low quality reproduction schematic.

Service manual for PD-310 had better description, schematic and PCB overlays but not an exact match for the PD-350.

Found Pioneer PL-L800 service manual had excellent circuit descriptions and fault finding. The PL-L800 uses the same chip set as the PD-350;

i.e. PD1003, PA2008 and PA2007.

The PD1003 crystal oscillator/divider was tested and found to be working OK.

Measured 9.8304MHz for the crystal and 2.400KHz (divide by 4096) and 120Hz outputs OK.

The remainder of the circuit operation is closed loop FG servo system.

Disassembled and checked the motor and tacho generator, then checked the front panel speed potentiometers, cleaned the pre-set speed potentiometers and checked the wiring and cleaned the associated connectors on all printed circuit boards.

During testing it was found that by removing the connector (CN3) on the motor PCB that goes to the speed switch PCB, one of two condtions occurred; 1) the platter speed would increase out of control and when the plug was reconnected, the speed would eventually return to normal control; 2) the platter would stop and not return to normal speed until power was cycled.

Found that moving the motor seemed to make a difference as to which condition eventuated.

The motor/pulley system was found not to be perfectly aligned with the belt (at a slight angle) and the belt would fowl with the motor guard bracket. This was addressed but the variability of the fault conditions remained.

It was thought that noise from the motor or other sources may be entering the feedback loop, so a shielding earth wire was attached to the motor and connected to the existing, nearby chassis earth lug. This helped reduce the variability of the symptoms but not eliminate the problem.

Again, disassembled and resoldered various connections inside the motor. When re-connected everything it was found that no power was getting to the motor control PCB.

The fault was traced to CN1 power connector soldering fracture. This was resoldered.

An intermittent power connection may also have been a cause of the original fault – or at least a major contributor.

More to follow.

Edited by Once Analog

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Thanks Vince,

 

I'm sure those more knowledgable about such things will appreciate the details of your approach to this. I'm just grateful for your skills and generousity. Wonderful stuff...

 

Cheers

 

M

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Well done, Vince! :thumb: 

 

Regards,

 

Andy

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Great work Vince, very educational, solder joints and carbonised contacts in connectors are the biggest issue as equipment age. Apart from caps drying out.

FYI,

After almost 20yrs of use of a power amp I use, I started to get a drop of gain in the left channel. When I cranked up the volume the left 6 feet ribbon started to developed sparks jumping to the outer frame. I thought I need a new amp, well the faults all turned out to be a loose spade connector in the left channel speaker protection circuit. Don't have either issues anymore!

Enough of me rambling on, just wondered if Uncle Mack has received his patient and if he has how its all going?

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just wondered if Uncle Mack has received his patient and if he has how its all going?

Pchan,

I still have the Luxman, will fit the tonearm this week.

It will soon be on it's way back to UM, certain he will give a full report.

Vince

Vince

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just wondered if Uncle Mack has received his patient and if he has how its all going?

Pchan,

I still have the Luxman, will fit the tonearm this week.

It will soon be on it's way back to UM, certain he will give a full report.

Vince

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As Vince mentioned,

 

I am waiting for the arm to be fitted and all tested. This will be held up a little perhaps by the wait for a new mat (5mm Achromat). I'm keen to have it back but after so long and so many disappointments, I am filled with trepidation. I will be VERY nervous when playing this and it will be some time before I will be able to listen without expecting a speed increase or variance... 

 

Vince tells me it's fixed and I believe him. But... :mellow:

 

Cheers

 

M

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Hi UM

 

Perhaps as a precaution and to save your frazzelled nerves you could get a power outlet remote controller from Altronics or jaycar so that if the dreaded acceleration occurred again you could kill the power real quick and prevent any damage to recrds, arms, stylus' etc.

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You Cassandra, you! :P

 

UM will not have a problem ... I am fully confident that Stuart's initial diagnosis, followed by the fine forensic work Vince has done, have solved the problem! :)

 

 

Regards,

 

Andy

Edited by andyr

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