Technics SL-150 refurb

[graham67]

I was lucky to pick this up on quiet eBay weekend last year.  It belonged to the seller's father and used to have an SME arm which was sold separately.  From the pics it looked pretty tidy so I drove down to south coast to pick it up.

The seller turned out to be a real audio enthusiast, exactly the type of person you want to buy off, we had a good chat and I didn't spend long checking out the machine as I knew it would be genuine.

Cosmetically it looked great as the seller had cleaned it up using professional cleaners and even polished the lid.  So I haven't posted any before pics as they won't look hugely different to the after ones!

However that didn't stop me from doing my usual detailing.  I first removed the base and unscrewed the collapsed rubber feet which is a common ailment on this series. I cleaned the base inside and out using foam cleanser and paint brushes to loosen any dirt.  There are some unsightly marks from having the power cable coiled under the base plate which obviously got a bit hot and the marks can be seen in the pics.

The top plate, and platter was cleaned in a similar manner and I used  a stiffer bristle nail brush on the strobe edge.  I cleaned the power cable and fitted a nice older MK plug I liberated from another purchase.  I removed the hinges to clean any trapped dirt.

I removed and cleaned the knobs and applied Deoxit to the pitch control turning them to ensure full coverage.  I dismantled the power switch and cleaned and greased the contacts.  Unlike the Q202 I worked on last year, the power switch is exposed and prone to deoxidation.  However the design is robust and fundamentally sound.  In fact, this description could apply to the entire machine which is well designed and easy to dismantle.  Almost everything is attached using decent quality small Philips screws that didn’t strip and all came free without applying undue force. And compared to the automatic models there is not much to go wrong. 

I cleaned up the wiring loom to remove that slightly sticky film that old plastic wiring can emit, and removed and polished the strobe lens. 

I removed the motor and noticed one of the bushes that cushion and decouple the motor from the top plate was missing. However after some rummaging about in my boxes of useful stuff i was able to fashion a suitable replacement using sticky backed high density foam and some centre punches.  The compliance was pretty perfect so thanks be to the great god Blue Peter which taught me most things can be fixed with household detritus and glue!

I removed the bearing end cap and liberally applied some genuine Techy direct drive oil to both ends, spun it around and then let it sit overnight  This really freed up the bearing and it now spins freely for a very long time.

I unplugged and removed the PCB.  I didn't like the look of the big 470uf cap so the board has been dispatched to be recapped.

I polished the lid using Meguires No 10 & No 17 clear plastic polish/cleaner which made it look even better and also washed and scrubbed the rubber mat in Fairy Dishwashing liquid.   This 5mm mat ended up on my parents Q202 so I have sourced an improved mat for this deck.

One of the bigger challenges was the feet, as the cutouts are designed to suit the small rubber hollow feet attached with tiny M3 screws.  The plastic base is quite thin so not suitable for Isonoe feet at least not without making modifications to strengthen the mounting holes.

I found the 40mm diameter cutouts perfectly housed halved squash balls, however these do deform with time so not really a good long term solution.

Then I had the idea to try 40mm sorbothane hemispheres and found these fit perfectly.  They even stay in place without any assistance which is just as well as tape or many glues don’t adhere to sorbothane. 

So all in all a very easy and enjoyable deck to work on, though unlike an old idler,  if something goes wrong it is likely to require the services of a skilled electronics engineer rather than a back yard mechanic!

The next challenge is working out how best to calibrate the variable resistors on the PCB  board when it is returned.  These are in addition to the trim pots accessible under the platter that act as coarse pitch controls.  The manual is not very precise in this regards, as it doesn't mention if a speed should be selected or if the platter should be spinning or not when performing the measurements!

Then comes the arm and armboard which I will report on in future.  "Its a Technics, should be easy"  I thought.  Let's just say that it proved more challenging than expected.  But with expert assistance it is all coming good .

 

[graham67]

The bottom plate cleaned up and sorbothane balls fitted into the cutouts for the original feet

 

[graham67]

Well laid out internals (minus main PCB), cleaned up top-plate, fabricated motor bush and main PCB showing bulging 470uF cap.

 

[graham67]

Another shot of the deck with original SME armboard.  The unusual and frustratingly non-standard cutout is also shown.  More of this in the next instalment!

 

[greybeard]

Graham, when you say unusual cutouts do you mean for technics arms or SME? What arm do you intend to fix? Great work as usual, these are fine decks, I had one given to me many years ago, in a very sorry state, after being stored in very damp conditions, I had to re-spray the top plate, so decided to change the colour to black. It is still giving Stirling service with the original arm, in my second system.

 

[Andrei]

Well done with the sorbothane feet.  Pretty much an ideal solution.

In the pic above you can see a fair bit of bare metal.  The TT will respond well to sticking dynamat to those empty areas.

As regards the bearing: is the same as in the Technics 1200 series?

 

[GJO]

I have one of these in the loft,but the condition is dire,ie paintwork damaged but it did work when I put it up there,needs a new home if anyone wants it.

 

[myles]

I have one of these in the loft,but the condition is dire,ie paintwork damaged but it did work when I put it up there,needs a new home if anyone wants it.

I nearly plumped for one of these a couple of years ago but baulked at the condition of the paint. It's a real shame because it sounded great, but I didn't think I'd have the skill to refurbish it. 

Do you think yours is saveable? If so, I'd like to have a go if possible?

 

[graham67]

Graham, when you say unusual cutouts do you mean for technics arms or SME? What arm do you intend to fix? Great work as usual, these are fine decks, I had one given to me many years ago, in a very sorry state, after being stored in very damp conditions, I had to re-spray the top plate, so decided to change the colour to black. It is still giving Stirling service with the original arm, in my second system.

Hi Colin,

The arm cutout is slightly smaller than the 1200/1210 and apparently some of the 1300/1400/1500 series.  It appears they standardised the diameter to 120mm on later machines, but this early 150 has a 119mm cutout and 3 awkward metal tags at 4:30, 8:30 and 12:00 which can get in the way.  The taper of the cutout is also different.

I will includes some more info on this shortly with pictures and an arm in place.  I will be trying out a couple of options so stay posted!

Graham.

 

[graham67]

Here is the first of the armboards I will be trying.  This was made by Shaun at Soundsupports to suit a 3pt Rega. 

Shaun is not currently producing the 4 hole Technics boards so he very kindly adapted an SL1200 board. He covered the 3 larger holes with dummy hex heads, and drilled 4 holes to suit the 150.

He then took a small amount from the circumference to reduce the diameter to 119mm and cut a taper to match.  He also made two cutouts in the lower platform to clear the extra metal tags on the SL-150.

I think the end result looks really smart.

 

[graham67]

And here is the arm in place.  Its a AO branded Rega RB202 I picked up on AoS.  I added an end stub and tungsten counterweight from an earlier RB300 which looks a lot nicer than the plastic stub and bulky black standard weight.

I will need to add some Soundsupport spacers to get the VTA right.

 

[graham67]

And here is the almost completed deck.  I still need to fit the recapped PCB, so I cant play any tunes yet! 

I managed to source a slightly scuffed Oyaide mat (which looks better in the flesh than in the photos!) at a decent price which suits the deck well.

The project has taken a bit longer than anticipated but I have learnt that patience is a virtue when it comes to hi-fi! 

I have another arm to try on this deck and will include details once it comes together.

 

[graham67]

Well done with the sorbothane feet.  Pretty much an ideal solution.

In the pic above you can see a fair bit of bare metal.  The TT will respond well to sticking dynamat to those empty areas.

As regards the bearing: is the same as in the Technics 1200 series?

Hi Andrei, 

I agree that would be good idea to damp the plate.  I will consider that once I have heard how it sounds.  I haven't owned a 1200, so I dont know if the bearing itself is the same, but the whole bearing/stator assembly on the 150is a different part no to the 1200. 

Graham

 

[Radioham]

To Set the speed n the SL1210 you use a frequency counter, with the platter removed.Details are in the service manual. It could be the same process for your deck.Look on Vinyl Engine.

Alan

 

[graham67]

hi Alan.

I have read (and re-read!) the service manual but instructions are rather opaque. It carefully states what cap & resistor to measure and the variable resistors to alter to get the required voltage but makes no mention of what configuration (e.g state of power up and speed selection) the machine should be in .

Btw, the 150 and all 1300/1400/1500 Mk 1 variants are servo controlled so setting of speed is quite different to the quartz locked techies.

thanks

 

[Andrei]

Hi Andrei, 

I agree that would be good idea to damp the plate.  I will consider that once I have heard how it sounds.  I haven't owned a 1200, so I dont know if the bearing itself is the same, but the whole bearing/stator assembly on the 150is a different part no to the 1200. 

Graham

Graham

If you do take out the bearing please post a couple of pics.  If it is the same - or close enough - to the SL1200 then I have some good suggestions.

 

[graham67]

I have finally completed the build of the SL-150 using a refurbished Micro Seiki MA-202 arm. The arm is about the same age as the Technics and both have that typical mid 70s Japanese aesthetic.  But it proved quite a challenging combination to put together!
 
I was fortunate to source the 202 from Robbiegong on AOS. Phonomac (Angus) had rewired the arm and fitted new ceramic bearings.  But it was only when I received the arm that I realized what a long arm post it had.   To compound matters, when I rested the arm on the SME plate, the arm sat directly above a protruding plastic moulding on the baseplate that retains the right rear foot! 
 
Using a dummy wooden cart and a thick 5mm platter mat I measured the remaining clearance under the armpost.  When I investigated the dimensions of common 5pin plugs it soon became apparent I had problem, needing to find a minimum of  5mm to make it viable.

I had several conversations with the very helpful Yannis Tome, who came up with a very low profile right angled SME style plug but with a shorter shank so the right angle is hard up against the arm tube.  This saved several mm against other options and proved a lifesaver.  Yannis also fitted compact RCA sockets so the cable could be threaded through the existing undersized exit hole in the plastic base plate.

Steve at Magna Audio built an ebony armboard with a deep cutout to lower the arm mounting collar to the same height as the SME and Rega armplates.    The aforementioned metal tags were to prove a real challenge, however Steve rose to the challenge and  modified the design with an angled section to cover the protuding tag in the cutout section adjacent to the platter.

Even the headshell was chosen to maximise clearance.  For example, when compared to a Technics DJ headshell, the mounting surface of a Jelco headshell sat over 2mm higher relative to the armtube, meaning the armpost had to be lowered the same distance which i was trying to avoid.  Fortunately Angus was able to source an excellent Audio Technica MS-9 magnesium headshell which is rigid, light and vitally has a low profile, saving further millimeters. 
Angus also recapped the PCB and after I recalibrated the speed control voltage it was all systems go.  I installed an old but still useable Audio Technica OC-9 ML ii so the deck could be directly compared to my resident 401.  Mounting the OC-9 cart was so much easier than with the Rega.  Just 2 bolts through the cart body directly into the headshell.  I used a spare set of Audio Technica leads as supplied with their higher spec carts.
The cart was aligned using a Stevenson based protractor for the MA-202 provided by Angus.  As the cart cannot move laterally, I only needed to align the straight sides of the MS-9 to the grid, then loosen a small bolt on the MS-9 which enables the socket to be slid fore/aft and rotated to get the correct overhang and azimuth.  The headshell had to be mounted quite far forward so i confirmed alignment using a different protractor.  The alignment proved near identical to the simple 2 point 9" alignment provided with the HFN test disc.
 
Compared to the nerve wracking process to setup  the OC-9 in a fixed headshell such as the Audio Note or Rega arms, it was a real pleasure to setup.  VTA is very easily adjusted using a sliding lever on the side of the post mounting.

The OC-9 was connected to a Phonomac upgraded Denon HA-500 headamp feeding the internal MM phono stage of a YBA Integre DT amp into JBL 4311s augmented by Townshend Audio supertweeters.
 
Sonically,  it was immediately obvious the presentation of the Technics / MA-202 combo is very different from the Loricraft Garrard 401 with Audio Note Arm Three V2.  It is crisper, more explicit, energetic and the soundstage is smaller and more focused .   The bass is not as deep but has great pace and rhythm and real snap.   To get a feel of what suits it best, I will be trying it out with a number of MC and MM carts, a job  made much easier by the detachable headshell and on the fly VTA adjustment !
 
I wish to thank Robbie, Angus, Steve, Yannis, Shaun and anyone else I may have forgotten for furnishing the parts and advice to get this deck up and running.





 

 

[wizmax]

Looks excellent Graham, I would like to hear it sometime.

 

[graham67]

Looks excellent Graham, I would like to hear it sometime.

You would be more than welcome to hear it Robin. I am.not far from Pete so drop me a pm when you are next in the neighbourhood .  The Denon head amp is a cracker, i got the inspiration  after hearing your room at keggy!

I will be trying a PTG2 on it next, on the 401 I prefer the OC-9 but suspect the PTG will put up a better show on the Techy.