Technics SP10 MK3 Restoration

rich121

Well-Known Member
Dec 11, 2017
54
12
73
Yakima, Washington
Just got my SP10 MK3 base (motor unit & controller) back from JP at FidelisAnalog.com
JP is one of the most knowledgeable on the SP10 MK3 and is the one who designed and manufactures the MN6042 Speed Control chip that keeps these and other Technics turntable models still operating.

My SP10 MK3 came with the stock Technics SH-10B5 faux obsidian base.
It has very low hours of use , no signs of wear at all on the bearing and not a single blemish, other than some specs of dust and a couple spots on the copper part of the platter that need cleaning.

**** I would like to have a 2 arm, constrained layer plinth built and have the motor unit mounted 'naked'. I am presently searching for somewhat 'affordable' plinth builders and suggestions would be greatly appreciated.****

The work that JP did to both the motor unit and the controller:

1. Pre-refurbishment measurement to baseline the performance of the unit and to see if there are any underlying issues.
2. Cleaning of all PCBs to remove the factory conformal coating. At~40 years this coating tends to become hygroscopic which can cause stability issues.
3. Physical inspection of all solder joints under an inspection microscope. Many of the joints will exhibit annular deformities which can lead to joint fractures down the road. These must be cleared of the factory solder and re-soldered. There will also be poor joints that need the same treatment. You can’t just reflow as the solder alloys aren’t the same which can also cause joint failure down the road.
4. Electrolytic cap replacement and rectifier diode replacement.
5. Disassembly and cleaning of the motor. Bearing inspection and service work. Proper Anderol 465 oil is used for reassembly. Motor is then checked for any areas of bearing drag.
6. The brake solenoids typically needs cleaned, and band tension is adjusted.
7. Stop/start and speed selection switches in the motor chassis are measured for contact resistance. Too high of resistance is indicative of a switch failure in the future. In the control unit I typically replace all the tactile switches, and the start/stop switch if needed.
8. Relocation of the brake regulator transistor to the heatsink to prevent overheating of the board (factory design flaw).
9. MN6042 replacement installation.
10. PSU ripple check at all critical stages (10).
11. Course calibration is performed and post-refurb baseline measurements for FG spectrum, motor drive phases, etc. are taken.

12. After 48-hour run-in final calibrations and verification measurements are performed.

The basic service returns the unit to factory or better specifications (assuming no permanent bearing damage has occurred). This service is quite exhaustive and very different from the typical work I see of just swapping some caps out, checking some voltages, and adjusting phase tracking.

The advanced service adds on top of the basic service:
1. Replace all polyester capacitors.
2. Replace drive circuit metal oxide resistors.
3. Replace all voltage regulator ICs and update circuits.
4. Replacement of certain diodes.

Rick
 

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wbass

Member
Jul 12, 2020
77
32
18
42
Did you also get the top of the chassis refinished? I like the coppery look.

FWIW, my (more) affordable SP10mk2 plinth came from Acoustand in the UK. Lee was good to deal with, patient, flexible. He might be a little backed up, but I'd imagine many places will be.
 

rich121

Well-Known Member
Dec 11, 2017
54
12
73
Yakima, Washington
Did you also get the top of the chassis refinished? I like the coppery look.

FWIW, my (more) affordable SP10mk2 plinth came from Acoustand in the UK. Lee was good to deal with, patient, flexible. He might be a little backed up, but I'd imagine many places will be.
That is just something weird with the lighting, interaction with the copper color on the platter...has the stock chrome? finish.

Should have mentioned I'm in the US and I believe I already checked with Acoustand and they don't accommodate a 'naked' type plinth.
 
Last edited:

thedudeabides

Well-Known Member
Jan 16, 2011
1,775
378
525
Alto, NM
Do you like how it sounds without any further mods?
 

rich121

Well-Known Member
Dec 11, 2017
54
12
73
Yakima, Washington
Do you like how it sounds without any further mods?
Haven't mounted it to the original Technics plinth. I want to get a 2 - arm custom made plinth and will probably wait until then to set it up.
 

Addicted to hifi

VIP/Donor
Sep 8, 2020
1,972
591
220
50
Australia
Just got my SP10 MK3 base (motor unit & controller) back from JP at FidelisAnalog.com
JP is one of the most knowledgeable on the SP10 MK3 and is the one who designed and manufactures the MN6042 Speed Control chip that keeps these and other Technics turntable models still operating.

My SP10 MK3 came with the stock Technics SH-10B5 faux obsidian base.
It has very low hours of use , no signs of wear at all on the bearing and not a single blemish, other than some specs of dust and a couple spots on the copper part of the platter that need cleaning.
but I would like to have a 2 arm, constrained layer plinth built and have the motor unit mounted 'naked'. I am presently searching for somewhat 'affordable' plinth builders and suggestions would be greatly appreciated.

The work that JP did to both the motor unit and the controller:

1. Pre-refurbishment measurement to baseline the performance of the unit and to see if there are any underlying issues.
2. Cleaning of all PCBs to remove the factory conformal coating. At~40 years this coating tends to become hygroscopic which can cause stability issues.
3. Physical inspection of all solder joints under an inspection microscope. Many of the joints will exhibit annular deformities which can lead to joint fractures down the road. These must be cleared of the factory solder and re-soldered. There will also be poor joints that need the same treatment. You can’t just reflow as the solder alloys aren’t the same which can also cause joint failure down the road.
4. Electrolytic cap replacement and rectifier diode replacement.
5. Disassembly and cleaning of the motor. Bearing inspection and service work. Proper Anderol 465 oil is used for reassembly. Motor is then checked for any areas of bearing drag.
6. The brake solenoids typically needs cleaned, and band tension is adjusted.
7. Stop/start and speed selection switches in the motor chassis are measured for contact resistance. Too high of resistance is indicative of a switch failure in the future. In the control unit I typically replace all the tactile switches, and the start/stop switch if needed.
8. Relocation of the brake regulator transistor to the heatsink to prevent overheating of the board (factory design flaw).
9. MN6042 replacement installation.
10. PSU ripple check at all critical stages (10).
11. Course calibration is performed and post-refurb baseline measurements for FG spectrum, motor drive phases, etc. are taken.

12. After 48-hour run-in final calibrations and verification measurements are performed.

The basic service returns the unit to factory or better specifications (assuming no permanent bearing damage has occurred). This service is quite exhaustive and very different from the typical work I see of just swapping some caps out, checking some voltages, and adjusting phase tracking.

The advanced service adds on top of the basic service:
1. Replace all polyester capacitors.
2. Replace drive circuit metal oxide resistors.
3. Replace all voltage regulator ICs and update circuits.
4. Replacement of certain diodes.

Rick
Great stuff and news.enjoy.
 

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