Logic DM101 Turntable set up problems

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Seems I'm a likely candidate to foist cantankerous equipment on.

Case in point: an 80s vintage Logic DM101 Turntable that the previous owner gave up on, saying it was a veritable "B*#*" to set-up.

I'm taking a whack at it and finding the process...indeed...daunting.

Balancing the floating sub-chassis on the three-point suspension system (comprised of six-expansion springs moored to the plinth) upon which the sub-chassis set screws attach themselves to (see pics) is proving near impossible.

The sub-chassis simply won't level out or center in the cut-away section of the plinth no matter how I adjust the leveling set-screws.

I have visited vinylengine and read through the set-up manual with no luck....so I am contemplating replacing the six suspension springs which don't seem uniform in terms of expansion-tension.

The second wonky (IMO) quirk of this system seems to be the centered main compression spring....

Does anyone have any experience with setting these up...any helpful hints? insights?

Thks...Leon
 

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The design of this turntable suspension was to ease the set up problem by having the three adjustable screws at the top.Apart from that, the arm connecting lead had to be coiled in such a way as to prevent any offset to the sub assembly.Given the age factor I would firstly make sure the connecting lead has not stiffened and secondly check that none of the springs have stretched.Sometimes it helps to add a piece of foam plastic or rubber inside the springs to provide light damping.
 
Thanks...but everything I've read about these seems to indicate they have always been problematic in terms of balancing and set-up...the Thorens, Ariston and Linn are a breeze compared to this wacky beast.

No amount of set screw adjustment seems to alleviate the leveling of the sub-chassis and checking the arm connecting lead and phono-wires reveals it hasn't hardened or shifted from its original position.

I am going to try six new springs and see if that improves the leveling, keeps it as is, or makes matters worse.

I will also disconnect the arm connecting lead as well and see what that does, if anything...thks for your observations VaNarn!
 
Did you get this sorted? There is a nack to setting this up but its fairly easy, vinylengine has the instructions or I can guide you through it if you like.

Thanks...yes..but the instructions are IMO horrible....and pretty much bereft of decent diagrams to illuminate the process...and after all the set-up, adjustments, a decent tonearm and decent MC cartridge...the Logic was not in any way superior to my ancient Ariston running a midddle of the road Nagaoka cartridge on a pertty ordinary Rega arm.:(
 
I did set one of these up 'back in the day' when it was only a couple of years old and would generally agree with the previous owners assessment! However, it was easy enough to get the chassis centered, so I imagine one or more of the springs has stretched. Always a bit twitchy even when nearly new. I'd put a hole through three 'soft shoe' style sorbothane feet and use those in place of the springs with the spring bolts used as guides. Did this with an early Systemdek relatively recently to good effect. This may require some simple fabrication to give the sorbothane something to sit on.
 
You Brits are entitled to you opinion, of course, but the mainspring upon which the weight of the sub-platter plinth assembly really rests, is horribly conceived and implemented! It is little more than a large bedspring...poorly manufactured, machined and engineered. At the price these were introduced for...I've heard and seen many better under that price point....I got it sorted out just fine but as I said before...the Dm101 makes a Linn, Thorens or any number of other finicky decks at this price-point seem easy to set-up...probably why it never achieved any commercial longevity or success...regards..Leon
 
Totally agree- no doubt conceived at the time with the best of intentions, but a silly idea nonetheless. With or without the centre spring, which was not on the deck from the start but added as a later 'fix', the configuration of the springs does nothing useful. Like I say, best removed altogether.
 
I found it very easy to set up and once there it stays there. One thing I did find is the cable for the arm passing through the centre spring, if you dont get this right all the adjusting in the world wont help at all, I often wondered if re-routing the cable might have made things easier. Also the orientation of the centre spring is important (according to Logic) as if done wrong can throw things off a little.
I use mine with a Logic Datum 2 arm and I think its a good table, better than my old Thorens/SME table which was a pain to set up, why turntable manufacturers think setting up a suspended table from underneath is OK is beyond me. I felt like a complete eejit lying on the floor underneath a record player balanced on two chairs trying to get the 'bounce' right , I'm glad none of my friends saw me. :eek:

Edit - your springs dont look worn to me, I did read somewhere that the outer springs were softened to accommodate the centre spring, the way your adjusters are sitting high one might assume yours was before this modification but after the centre spring modification. If you do modify it and no longer need the springs I would be interested in taking them off your hands if your random spare spring box is full.
 
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Yes...rerouting the cable made things a lot easier to set up. It's not a bad TT, but the engineering of the suspension system particularly the center mainspring is ridiculously inept:eek: IMO...I like keeping things as simple as possible...and in this respect I simply don't hear an appreciably better result from finicky turntables like this and the Linns, Thorens etc. over meat and potato TTs like my Empire 298 or my Lenco L78.

And in the end that's what I am looking for...some quantum improvement over what I already have....particularly if the original price point between the items was as significant as in this case.

In any event I quickly disposed of this TT by trading it to a fellow enamoured by such complexity:warped:...I would note that upon moving the Logic to his domicile...we were forced to set the screwy beast up again almost from scratch.

We kept it stock...so sorry robgilmo, no spare springs kicking around...but thanks for your input, observations and advice...much appreciated...yours too...Toaster and VaNarn:)
 
Inherited Logic DM 101

Hi guys, I found this turntable at the back of my uncle's garage which has been sitting there 20 years in a rather sad state..

- On stripping it down notice the springs are all of different tensions ! Does anyone know where to get new ones from ?

- Also I notice that others have done away with the power switch, Any reason for this ?

- The arm mount is for an SME but the only arm I could find in his garage was a Rega / Moth 250.

- Lastly what sort of cartridge price range should I look at for this turntable / amr combo ?

Any thoughts to help me on my way much appreciated
 

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Hi,

Some applied logic (sorry) will indicate indeed the springs
are of different tensions, they have to be for the different
loads that they support. Pair them up then arrange.

However they are too stiff laterally for the subchassis
rotating around the platter, and a later version used
a large central coil around the main bearing and much
reduced (but still different) stiffness spring pairs.

YMMV about the cartridge.

https://www.thakker.eu/en/pickup/audio-technica-at-95-e-cartridge/a-4916/
Is a bargain and will get you going, or this :
https://www.thakker.eu/en/pickup/thakker-epo-e-cartridge/a-5207/

https://www.thakker.eu/en/pickup/audio-technica-at-440-mla-cartridge/a-4922/
Is a great long term buy for a well fettled turntable.
Top quality and the tip will last utterly ages, e.g. >
3 times as long and will always be better than this :
https://www.thakker.eu/en/pickup/audio-technica-at-120-e-cartridge/a-4919/
Which is a good match for the arm and turntable,
and the best budget nude tipped elliptical.

rgds, sreten.

Note : to get it to really sing requires a lot of non-obvious fettling,
like most suspended turntables, the devil is in the details.
The details are not expensive, they are sympathetic empathy.
 
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Thanks Sreten, handy to know about the springs, thought odd some were shorter than others, need to work out where they go. Yes mine has the big central spring.

The arm has no wires in it, these people seem pretty expensive:

Rega Tonearm Modifications & Rewire

Cartridge fancy a Goldring, as they use to be made down the road from me when I was a kid and remember drooling over the Lenco turntables in the showroom window.

Also need a phono amp...
 
Hi,

Good you have the central spring relatively.

The shortest spring pair will go behind the arm.

No arm wires ? That complicates things a lot.
(You can't use the old wires to pull the new
wires through the 90 degree bend, grim ...)
Its gets very complicated.

If you fancy a Goldring be prepared to pay loads
more money for no better than my suggestions.

What amplifier do you have ?

rgds, sreten.
 
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The ones with the highest tension are at the front, the other pair are rather weak. One of the arm springs is broken.

Ya no wires in the arm a real pain, that link I gave earlier they do it for you, but seems their wires are in two parts, internal and external... and pay twice ?

Rega Tonearm Modifications & Rewire

Where as wires on ebay are one piece:

Rega Cardas rewire kit for RB250, 300 tonearm etc. | eBay

My amp is a heavily modded Yaqin MC10L
 
Sounds good to me, as got a couple of springs missing. Does anyone have any pics of this mod by any chance ?

I did set one of these up 'back in the day' when it was only a couple of years old and would generally agree with the previous owners assessment! However, it was easy enough to get the chassis centered, so I imagine one or more of the springs has stretched. Always a bit twitchy even when nearly new. I'd put a hole through three 'soft shoe' style sorbothane feet and use those in place of the springs with the spring bolts used as guides. Did this with an early Systemdek relatively recently to good effect. This may require some simple fabrication to give the sorbothane something to sit on.
 
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