Almost Stupid Easy - Technics SL-1600 MK1 Restoration

 

About two months ago, I scored two direct drive turntables for $60: a Pioneer PL-518 and a Technics SL-1600 MK1. Either one of these decks alone would've been a steal at the price, and a huge upgrade from the old Garrard 770M I was spinning LPs on prior. Unlike the Pioneer (which has been such a nightmare that it deserves it's own post), the Technics managed to survive it's two decades of horrible storage in relatively great shape. It just needed a little love.

Technics has this practically legendary reputation among turntable enthusiasts, in large part to the popularity of it's SL-1200 MK2 by both DJs and home listeners alike. But while the 1200 lives on and new variants of it are still in production, Technics had made more complex, and arguably more exotic turntables with various creature comforts like a suspended chassis, changer mechanisms, and automatic operation back in the brand's heyday. The SL-1600 MK1 was one of those turntables, and my eyes practically fell out of my skull the minute I saw this thing in the flesh.

When people say this turntable is built like a tank, they mean it. Carrying this thing out to the car and this thing felt like it could stop armor piercing bullets with just how heavy it was. The entire plinth is made of cast aluminum with a 'floating' chassis. The inner pan - where the platter and tonearm are mounted, sits on springs that isolate the components from unwanted vibration. 

The only things I could immediately see that were wrong with my 1600 was a missing headshell and counterweight, a severed grounding wire, and the dustcover was cracked and a bit cloudy. Also, when I plugged it in for the first time the speeds were not holding steady, and the tonearm would erratically move when it tried drop on a record. It would also drop the arm far too fast. You'd think all that weight would amount to this thing being chuck full of complex inner workings, but it's not. Pull the platter off and take the four screws holding the cover out, and you'll find it's surprisingly sparse on the inside.

There really isn't a whole lot going on here. You have the motor hub in the middle and a board that handles power delivery and speed control on the left. The power switch, and all the linkages for the tonearm are located on the right side of the plinth. The bulk of this all lifts out with the plinth, allowing unobstructed access to the tonearm.

Since I was having speed control issues, my attention was set on the potentiometers in the bottom left corner of the plinth, and the smaller ones on the main board itself. I hosed these out with CRC QD contact cleaner and gave the pots several cranks to break up any gunk built up on the contacts. This took care my speed control problems, though if they still persisted, that's usually a sign that the board needs it's capacitors replaced. For electronics this old, that's usually a necessity but I can at least get away without it for now.

At this point, lifting the plinth was a simple as removing the four screws for the feet on the bottom of the turntable and unplugging the cables connecting the two halves. The tonearm then lifts out after removing three screws - two of which are hidden under rubber caps.

The little spring loaded brass cylinder in the top right of the mechanism is an oil filled damper that slows down the tonearm as it drops onto the record. Over time, this fluid goes bad and it needs to be replaced. I picked up a little syringe of 300k viscosity silicon oil off eBay, pulled off the C-clip, and cleaned up the cylinder before generously coating it with the new oil. While I had the tonearm out, I also regreased the anti-skate mechanism with white lithium grease. Now the anti-skate works properly, and the tonearm drops nice and slow. 

As for the erratic swinging of the tonearm, the culprit was once again - you guessed it: old grease. This T-shaped piece of plastic has this brass bushing in it that was so seized up with grease that it was practically fused to the shaft it rotated around. You can see the crack in the plastic that I imagine formed due to the unnecessary stress (and perhaps aged plastic), but it was still a snug fit, so I wasn't concerned about it affecting functionality.

Getting this piece off the shaft proved to be a bigger pain in the ass than it looked. The tolerances on the pieces are so low that no amount of pulling, even hammering and heat application were enough to free it. What finally got it free was a pair of angled tweezers, stuck under the bushing, and then leveraging it up. A thorough cleanup with IPA and some new grease, and the automatic tonearm was working good as new.

The last bit of internal work I needed to complete was the replacement of the grounding wire. The original one was completely hacked off, so I desoldered it's remnants and replaced it with a line of 20-gauge stranded copper wire and added a new spade terminal to the connection point.

With the internal work finished, I now had to source a new counterweight and figure out what I wanted to do for a cartridge and headshell. Thankfully an original counterweight was available on eBay around the time I brought the turntable home so I snatched it up and installed it as soon as it arrived.

I opted for a dirt-cheap generic Technics knockoff for the headshell since original SL-1600 headshells are stupid expensive, and the mounting system is really strange on them. The quality seemed fine and I couldn't imagine it would have a noticeable effect, if any at all on performance. The cartridge was just my old AT-VM95, except I swapped the conical 'C' stylus for the higher end microline 'ML'.

The main problem with the microline is that it far more sensitive to fine adjustment than the conical. On my Garrard with it's chintzy-ass tonearm, the conical sounded basically fine. That would not fly with the microline, despite it sharing the exact same cartridge body. I 3D printed two alignment tools: an overhang gauge and an alignment protractor which helped get those dialed in pretty quickly. 

However, there was one aspect of adjustment that I couldn't account for as easily: vertical tracking angle, or VTA. The MK1 SL-1600 does not feature VTA adjustment, so I couldn't bring the tonearm parallel with the record per the cartridge's setup requirements. At least not with the turntable itself. I was able to accomplish this by sticking a second felt slipmat on top of the existing one, and by shimming the cartridge with 3D printed washers. I think there's still a little room for improvement here, but for lack of a better solution this seemed to work just fine.

That left the dustcover as the last thing I wanted to address. I did initially try polishing the original cover like I did with the Garrard's, except instead of using a headlight restoration kit like last time, I used bog standard sandpaper up to 10000 grit on a sanding block and a can of Meguiar's headlight coating. This... did not go well. Maybe I was impatient, but this stuff did not seem to want to dry completely, and attempting to sand and polish it made a horrible mess. I ended up just throwing it away. It was already a little cracked, but my botched restoration made it completely undesirable. Direct replacements are not an easy to thing to obtain either, or cheap.

The good news is that enough people have been shit-out-of-luck on dust covers for their vintage turntables that some have modeled adapters to fit dustcovers you can just buy off Amazon for under a hundred bucks. I found this adapter on Thingiverse specifically for the 1600 and it's closely related turntables, designed to fit a standard Reloop branded dust cover. It screws right in place of the original mounting brackets and the cover itself is a perfect fit - and makes the turntable look downright gorgeous.

This deck really turned out pretty spectacular. Granted, I didn't really do a substantial amount of work to it. The thing damn near worked the first time I plugged it in, and all my work was down to just cleaning, relubrication, and replacing parts. But that's a testament to how well built the SL-1600 is. That after four decades, no major electrical, mechanical, or cosmetic work was needed to get this puppy turning LPs again - something it is still very, very good at. It's dead silent, holds speed fairly well, and the suspended chassis does it's job. Not even my new, slightly overkill bookshelf speakers rumbling away on the top shelf could get this thing to skip.

Plus, the AT-VM95ML is just the icing on the cake. It really draws out the finer nuances in a record that you normally wouldn't get in a stylus that doesn't track as well as the microline does. But, to my ears it doesn't lose much of the punch I liked from the regular conical VM95C either. So there you go: a turntable setup that 'almost' makes my grandparent's record collection sound as good as something ripped off a CD - but with a lot more tactile fun. I can honestly see this being the last turntable I ever own, unless something absolutely bonkers like an SL-1000R falls into my lap in the future. Since my chances of getting struck by lightning are probably higher than that ever happening, it's hard to go wrong with an old champ like this.