1975 Technics SL-1500 MKI Megamod

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1975 Technics SL-1500 MKI Megamod

Postby Shannon Parks » Thu Mar 13, 2014 1:29 pm

After a six year hiatus, I'm back on the "I wanna build a turntable" kick. Obtained a non-working but good motor SL-1500 MKI from my buddy JT in a trade. So I'm trying to do a super low buck, 12" tonearm table. Instead of outlining everything I'm planning to do, I'll just blurt out bits and pieces as I do them. But I think this project is much less grandiose than my previous ideas, and I think I can get this one finished in a few weeks of spare time.

Blurt #1: Old Latex Paint for Chassis Damping?
The SL-1500 MKI is a light-weight for how many cubic inches it takes up - a mere 17.2 pounds. No one will confuse it for an SL-1200. Since the plastic underbelly/plinth is pretty cavernous, I'm thinking I can easily coat the bottom with a gallon of old latex without getting in the way of any mechanisms or motors. I'd probably coat the bottom with a 1/4 gallon at a time and let these layers dry. I think I can add 7 to 10 pounds of mass this way and not screw up any air cooling or anything. By all means, let me know if you think this is a horrible idea.

The rubber feet are almost 40 years old and dried up like last years morels. The feet pockets are almost 1.5" - just large enough for some sorbothane sticky feet. Purchased four 50D 1.25" feet for $15 (I'll keep a running budget total):
http://www.ebay.com/itm/181256711001?va ... 1439.l2649

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Re: 1975 Technics SL-1500 MKI Megamod

Postby Geek » Thu Mar 13, 2014 2:15 pm

Very cool! (y)

The guy I'm working with now would drool over that motor.... he rebuilds TT's and makes custom plinth's.
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Re: 1975 Technics SL-1500 MKI Megamod

Postby TomMcNally » Thu Mar 13, 2014 3:45 pm

I just acquired two of these SP-10 MK2's. One needs some work, it runs wide open, this one is good.

Gregg - does your friend sell custom plinths at reasonable prices ?

Shannon, will your house will smell like fresh paint when the motor warms up? ;)

I might have an ailing SP-15 or SP-10 as trading material.

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Re: 1975 Technics SL-1500 MKI Megamod

Postby Geek » Thu Mar 13, 2014 9:57 pm

TomMcNally wrote:Gregg - does your friend sell custom plinths at reasonable prices ?


Yes! He sells custom plinths. Prices are reasonable for my neck of the woods. Will PM you his addy.
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Re: 1975 Technics SL-1500 MKI Megamod

Postby Shannon Parks » Fri Mar 14, 2014 5:29 am

TomMcNally wrote:Shannon, will your house will smell like fresh paint when the motor warms up? ;)


Good point. I'll be sure to use water-based latex and not any leftover oil-based Kilz. (lol)

TomMcNally wrote:I might have an ailing SP-15 or SP-10 as trading material.


Trades are great anytime, Tom! That'd be a stack of Clementine and GSG boards. I looked at those Technics models two years ago, but the prices were just too high for units that needed repair.

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Re: 1975 Technics SL-1500 MKI Megamod

Postby 20to20 » Fri Mar 14, 2014 8:11 am

Shannon Parks wrote:I think I can get this one finished in a few weeks of spare time.

[ By all means, let me know if you think this is a horrible idea.

Shannon


Did you want to use this by Christmas ...2015?

I think the paint will skin over and the underlying goo will take 2 months for each level to cure out solidly. Very interesting idea, though. Cheap if it's your leftover old paint you don't want to pour it out behind the neighbor's fence. Heeeheee! But if you are in a hurry and want to spend a little on some epoxy paint it might work better. Since the laytex is % water it's going to shrink in weight, too. The lable should have the weight ratio.

Will the suspension/feet springs/ whatever it has, hold up to the higher weight?

You might try some of those small galvanized steel Simpson plates from Homers and epoxy those in if they'll fit. A couple fists full of those won't break the bank and they weigh quite a lot in a short stack.
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Re: 1975 Technics SL-1500 MKI Megamod

Postby Shannon Parks » Sat Mar 15, 2014 10:55 am

Pic #1:
Pic on the inside of the bottom cover. Large shallow area for the latex pour!

Pic #2:
Bottom outside. I think I'll just clean it up and re-feet it.

Pic #3:
An old crusty foot. I have to yank off what rubber is left, use pliers on the screw head while removing the nut (gooped with 40-year-old locking resin).

Pic #4:
A new foot. Sorbothane 50 rated for 5 to 10 pounds. Made in Kent, Ohio near where I grew up. So four will be rated for 20 to 40 lbs. They protrude exactly as much as the old feet, but I may sand the rim down 0.100" or so for good measure.

Pic #5:
Need longer tonearm wire for the 12" arm. Old wire was .016" and this is .027". Some vendors sell much thicker wire - beware. I'm going to reuse the SME style boot. I like these a lot, since I swap carts all the time. Note that I think I need to have a headshell inserted when resoldering, else I think these will then spring apart. We'll see if I remember. I need around a 17 or 18 degree offset angle. I think I'll just repurpose the old S-arm tip and bend it as needed and connect it to the 9mm carbon fiber tone arm (arrow shaft).
eBay Link for $7.49 shipped: http://www.ebay.com/itm/181326206742?ss ... 1439.l2649
Attachments
1.JPG
Pic on the inside of the bottom cover. Large shallow area for the latex pour!
1.JPG (865.01 KiB) Viewed 5128 times
2.JPG
Bottom outside. I think I'll just clean it up and re-feet it.
2.JPG (974.98 KiB) Viewed 5128 times
3.JPG
An old crusty foot. I hate to yank off what rubber is left, use pliers on the screw head while removing the nut (gooped with 40-year-old locking resin).
3.JPG (471.45 KiB) Viewed 5128 times
4.JPG
A new foot. Sorbothane 50 rated for 5 to 10 pounds. Made in Kent, Ohio near where I grew up. So four will be rated for 20 to 40 lbs. They protrude exactly as much as the old feet, but I may sand the rim down.
4.JPG (469.64 KiB) Viewed 5128 times
5.JPG
Need longer tonearm wire for the 12" arm. Old wire was .016" and this is .027". Some vendors sell much thicker wire - beware.
5.JPG (516.01 KiB) Viewed 5128 times
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Re: 1975 Technics SL-1500 MKI Megamod

Postby Geek » Sat Mar 15, 2014 1:58 pm

Need tonearm wire? That Kynar wire-wrap stuff is as light as stock wire ;)
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Re: 1975 Technics SL-1500 MKI Megamod

Postby Shannon Parks » Sun Mar 16, 2014 5:54 am

Geek wrote:Need tonearm wire? That Kynar wire-wrap stuff is as light as stock wire ;)

30AWG like this? eBay Link Do you know what the OD dim is?

BTW, I think I'm ditching the latex damping scheme for now. The motor and drive PCB both protrude much further into the bottom shell than I realized. I may still add a few pounds of silicone one the front and sides. I can get discount tubes of it for $1.50 at Menards. Easy to cut and adjust if needed.

So now I can go straight to the tonearm assembly. Planning to use a Hammond 1550LBK (7" x 5" x 3") filled with lead. Maybe I'll have this going today?

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Re: 1975 Technics SL-1500 MKI Megamod

Postby EWBrown » Sun Mar 16, 2014 1:34 pm

Perhaps that magical mystical "rubber sealant in an aerosol can" which is endlessly advertised on TV might work better, instead of using latex paint (???) [:)
At least it would set up and dry in a relatively short period of time.

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my dva rubles worth....

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Re: 1975 Technics SL-1500 MKI Megamod

Postby Geek » Sun Mar 16, 2014 2:09 pm

Shannon Parks wrote:
Geek wrote:Need tonearm wire? That Kynar wire-wrap stuff is as light as stock wire ;)

30AWG like this? eBay Link Do you know what the OD dim is?


That's the stuff!

Dunno the diameter, I just went by the weight on the milligram scale per equivalent length un-tinned chunk. It was the same or lighter.

Cheers!
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Re: 1975 Technics SL-1500 MKI Megamod

Postby Shannon Parks » Tue Mar 18, 2014 12:59 pm

EWBrown wrote:Perhaps that magical mystical "rubber sealant in an aerosol can" which is endlessly advertised on TV might work better, instead of using latex paint (???) [:)
At least it would set up and dry in a relatively short period of time.


LOL, Ed! I was *totally* looking at some of this stuff the other day at Rural King (a store where we Illinoisans can buy chickens, guns, clothes and fencing materials while eating free popcorn).

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Re: 1975 Technics SL-1500 MKI Megamod

Postby snitch56 » Tue Mar 18, 2014 11:55 pm

Shannon Parks wrote:LOL, Ed! I was *totally* looking at some of this stuff the other day at Rural King (a store where we Illinoisans can buy chickens, guns, clothes and fencing materials while eating free popcorn).
Shannon


Fond Memories of the Rural King where the aroma of freshly popped corn fuses with new tractor tire smell. There also always seems to be no place to park because half of the store’s inventory is in the parking lot (bricks, cattle fence, corral panels, go karts, etc.). I always like how they keep the electric cattle prods easily accessible so anyone can test them prior to purchase, it seems like an accident waiting to happen. It is a great store that I have spent hours just walking around looking for something that I probably don't need.
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Re: 1975 Technics SL-1500 MKI Megamod

Postby nyazzip » Tue Mar 25, 2014 12:33 am

never been to a Rural King but i'm guessing it might be like a Farm and Fleet?

I'm thinking I can easily coat the bottom with a gallon of old latex without getting in the way of any mechanisms or motors.


you might be able to screw in pieces of asphalt roofing with sheet metal or short drywall screws, as a dampening material. it is easy to cut and you won't have to wait several years for it to dry. if you do go the latex rout, i suggest you liberally sprinkle in some sand or gravel to optimize mass. heck you can even try pouring in mortar or joint compound or other concretes, but i have doubts as to how it would adhere to the plastic chassis...
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Re: 1975 Technics SL-1500 MKI Megamod

Postby Geek » Tue Mar 25, 2014 3:27 am

Shannon Parks wrote:....Rural King (a store where we Illinoisans can buy chickens, guns, clothes and fencing materials while eating free popcorn).


We have a chain under the brand of "Co-Op" that's pretty much the same. Jeff Foxworthy would love it! Walmart for rednecks! (lol)
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