Need Technician Advice - Technics SP-10 Mk2

Hello Everyone!

Long story short - I had a SP10 Mk2 from new, but sold many years ago. I missed it very much, lately I bought back two heavily used units. 1st one came with PSU, and the 2nd just the player.

Following are immediate issues:

I used this only PSU to test the 2nd player. As tested by a strobe print-out, all speeds work. On speed indicators, only 33rpm lite up. I thought the immediate TR116 and TR117 are in trouble. I swapped TR115 with TR116, but nothing changed. I don't think I would use 45 & 78 rpms anyway, however, if it is an easy fix, would like all indicators to work, when selected.

This 2nd player did not have neon, it came with just 3 unsoldered LEDs hanging on that spot, and one turned dead on my hands. I finally finished the LEDs from what I have (maybe the MCD too high, little too bright). I connected them to the 5V and N2, that learnt from some forums. Unfortunately, on spinning, couldn't see the expected platter strobe bars. FINALLY, after many long days, I found out that the 140VDC from PSU must be disabled. In my case, it was just 63VDC. Luckily, nothing got damaged. No body ever cared to mention this over the forums.

Back to my 1st player.
1/. The Neon used to be flickering. I thought it was the Neon gone aging. After I replaced the two caps on PSU, brought it back to 140VDC, Neon problem solved.
2/. On running the 78 rpms, the platter was shacking, especially on start up moments. Could this be something, again, the caps, when they are "hungary" ?

Both players were heavily used, with a lot of oxidation, on the 2nd unit in particular. They should be off service from broadcasters, I guess. Should I or should I not go another step replacing the ball bearings? I tried, but I just couldn't remove the end-caps.

Look forward to receiving solid technical words. Thanks reading!
 

warrjon

Member
2011-02-04 10:10 am
Vic
To fix this TT you will need a scope.

Download the manual from Vinyl Engine and perform the period adjustment first. If the period adjustment way out it will cause the platter to shake. You may need to adjust the period multiple times.

I had this problem with mine after I repaired the Control Board. Someone had wound VR1 and VR2 way out.
 

warrjon

Member
2011-02-04 10:10 am
Vic
I have been a tech for 40 years and it took me a couple of hours to get my SP10 working, these are not easy to fix if they are a mess like mine was.



Ok that could be dry joints on the PCB's. I had more than 10 dry joints and re-soldering ALL of the joints on all 3 PCB's fixed a few niggling issues, after I replaced a faulty transistor and removed the modifications made by the previous tech.


I would suggest re-soldering ALL components on ALL PCB's. I know it's a lot of work but beleive me it is worth it. These were wave soldered and after 40 years or even less the solder joints crack with heating and cooling. I have repaired dry joints on equipment still under warranty.


Next check the voltages from the power supply with the TT running, you can do this by removing the top cover of the PS. The 5 and 32.5 volts are adjustable. Get them as close as you can to the nominal voltage.



Once you have done that I would suggest youtube and learning to use the scope. You will need to know how to use it to have any chance of repairing the SP10.
 
= re-soldering ALL of the joints on all 3 PCB's

= I would suggest re-soldering ALL components on ALL PCB's. I know it's a lot of work but beleive me it is worth it. These were wave soldered and after 40 years or even less the solder joints crack with heating and cooling. I have repaired dry joints on equipment still under warranty.

= Next check the voltages from the power supply with the TT running, you can do this by removing the top cover of the PS. The 5 and 32.5 volts are adjustable. Get them as close as you can to the nominal voltage.

= Once you have done that I would suggest youtube and learning to use the scope. You will need to know how to use it to have any chance of repairing the SP10.[/QUOTE]

Hi, Your recommendation is highly appreciated. It would be a bold step for me to re-solder complete pcb's, and / or to replace most if not all of the components. Discrete components are easier to deal with than SMD's. I will try and learn step by step. What would you think if I blow hot air over the solder, as if the paste were running through a reflow oven?

Likewise will, pull out the storage scope to see what I can understand from its panel. I hope the manual is still there, but not sure. When I am ready, I would check and test what would have caused the 1st player to shake on 78rpms, before "warming up".

GOOD NEWS!
I finally fixed the 2nd player's speed indicators. Efforts pay off.
I downloaded the schematic diagrams last night, giving them deep thoughts before going sleep. This afternoon, I started to trace the pulse signals (voltage) from TR's back to the logic ICs, but I found nothing obviously wrong. When I was about to give up, I gave the LED pcb and upstream connector a test, come on, some wires and pads were discontinous. OMG, under a magnifier, there were 4 hairline cuts over the clads. This 2nd player was abused in the hands of the "tech guys" or whoever.

I still want inputs from Technicians like you. Should I or should I not to replace the ball bearings. Looks like tedous. These are decades old gear, who knows when they will stop to serve.
 

warrjon

Member
2011-02-04 10:10 am
Vic
I have 2 SP10's the one that came from a radio station was a mess. The tech had done some dodgy repairs. A lot these player were abused.

You do not need to replace or remove any components, unless they are faulty. Just re-solder the bad solder joints. If your eyes are good you can see bad solder joints they have a halo crack around the component leg. I used to be able see these but old eyes now I cannot see bad joints so I just re-soldered all of them.

Unless you have experience I would not use hot air just a soldering iron, everything is through hole. If you have liquid flux or a flux pen just flux the joint and heat it with the iron, the joint will re-flow. If you don't just use solder to re-flow the joint.

If you have 1 working TT use it and enjoy.

Then learn with the other one. Pull the scope out and learn to use it on the not working TT. Once you are familiar and can adjust the period on this then adjust the working one. There are a few other things to look at but you'll need to understand the scope first.
 
Thank you for your valuable tips. Will follow as needed.

Tonight I was in kinda good mood after fixing the speed indicators. Like most people, I wanted to give the old new-comers the best things to start. It was just a step away from removing the end caps, to understand the design / structure and to check the ball bearing condition. I thought hot air gun can help to loosen the end caps. Then I found following post. It changed my mind completely. It also tells me, from words between lines, the ball was fit-seated onto bushing, and doesn't rotate against the die-cast alloy end cap. The spindle that holds the motor rotor (the magnet) and platter spins on top of this ball care of a plastic raisin cap. Wear and tear should be little, maybe, except on the cap. So, I am going to let the TTs run until noise detected. I rather like to enjoy my music than to keep tossing around. Oh yes, to make them each a good plinth is the next, and to brush up the oxidation.

Yes, both my TT's spin and can lock on speed, except the 1st one that shakes on 78 rpms without a warm up. Will fix it when I learnt enough. This maybe my last post on this topic. Again, thank you subscribing ideas and thank all for reading!

(wanted to include a spindle pic i found, but couldn't link it to here)

Technics SP-10 MK2 Bearing | fidelisanalog.com

(above link was updated)
 
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warrjon

Member
2011-02-04 10:10 am
Vic
I replaced the thrust cap with Torlon and bearing with silicon nitride.


Does it make a difference - I don't know as I have not run the TT. Opening the bearing revealed a lot of gunk which was cleaned out. The thrust cap was worn so I replaced it and bought the kit with the ball.


If you do try to use the scope, the first thing to know is to only attach the probe's ground clip to ground,
never anywhere else. The probe's ground clip is connected to the utility ground inside the scope.


Good point. Be very careful what you attach the scope probe earth clip to. If it's live for example an amplifier output you will ground it and could blow something up. We had switchable earth on the bench scopes for this reason.
 
From the author of that post, it’s worth inspecting and cleaning the bearing. When the thrust pad wear becomes excessive the top hat will rub the stator coils. You don’t want that to happen.

I know it wasn't me. I wouldn't let my TTs slip away without a clean up on moving parts. For the time being and until I am more comfortable of taking them apart, I just let them run and enjoy my music with the mod'ed, extended arms. A Grace and a SME Siii, extended on different reasons.

Where that plastisc pad sits? Before last night, I was confused of SP10 Mk2 spindle configuration. I was in the belief, just like the Ariston below, traditionally a spindle (grinds on) ball (it again, grinds on) end-cap.

I actually had in mind getting ceramic balls as I would buy for my pair of Aristons (RD11 & RD11s). They were bought after reading the Linn Cult story, one after the other and were within my lean budget. The 1st came with ball missing, so the platters were rubbing down. The 2nd one had a corroded ball. They are now spinning, on 1/4 balls I recovered from a rusty sealed thrust ball bearing I incidentally picked up from backyard alley, believed to be dropped by scrap metal guys.

I'm open to hearing about balls and pads. What would be the best or better choice?
 

warrjon

Member
2011-02-04 10:10 am
Vic
The ball is 9/32 and is an interference fit in the spindle so the ball does not turn.


When I removed mine the ball and the thrust pad had noticeable wear on them. The ball also had a ring around it where it fit in the spindle housing. There is a member on diyaudio that made Torlon thrust pads User510 is his handle.


Here is the thread
SP-10 mkII, the next project


.
 
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The ball is 9/32 and is an interference fit in the spindle so the ball does not turn.


When I removed mine the ball and the thrust pad had noticeable wear on them. The ball also had a ring around it where it fit in the spindle housing. There is a member on diyaudio that made Torlon thrust pads User510 is his handle.


Here is the thread
SP-10 mkII, the next project


.

Thank you for ball size and thrust pad maker handle.
I guess that 1/32 extra makes ball tight-fit. :)