technics sl-dl1 linear turntable repair questions

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fscl
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Re: technics sl-dl1 linear turntable repair questions

Post by fscl » 14 Sep 2018 00:18

stanwebber wrote:the worm gear pulley was detached & loose when i received the unit so it's possible a washer or spacer may be missing. the configuration i have is:

brass pulley - washer - stanchion - washer - plastic wormgear - stanchion - pinwheel

can anyone confirm if i'm missing an extra washer/spacer? otherwise, the sl-dl1 came complete except for the topside repeat and up/down cuing buttons.

the guide rod is distinctly different on this model. on all other technics linear trackers i've examined the guide rode is perfectly smooth coated steel always lubricated with a lightweight grease. the sl-dl1 guide rod has a slight texture to it and may or may not be coated. ......snippage......
I have a feeling that this unit passed Matsushita QC with a sub par guide rod causing sticktion between the rod and barrel.... :shock: :-k

I've also got a non working DL1 that I still need to work on. Sold as a parts unit, it was destroyed / guaranteed to come in more parts in transit by USPS. The base plinth is cracked through and the tonearm drive belt is broken. Will have to get back to you what's on both sides of the worm gear.

Here's a topic specific to the DL1 and thumping / heartbeat:

https://www.vinylengine.com/turntable_f ... 18&t=80864

Sounds like you need some adjustment of the servo control of the tonearm since the tonearm is leaving the sled behind on the lead out groove:

https://www.vinylengine.com/turntable_f ... 28#p527228

Good luck, HTH

Fred

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Re: technics sl-dl1 linear turntable repair questions

Post by stanwebber » 14 Sep 2018 17:30

fscl wrote:I've also got a non working DL1 that I still need to work on. Sold as a parts unit, it was destroyed / guaranteed to come in more parts in transit by USPS. The base plinth is cracked through and the tonearm drive belt is broken. Will have to get back to you what's on both sides of the worm gear.
this turntable is a tank. how on earth did the aluminum get cracked? what condition did the box come in?

i did some extensive reading of the forum posts you referenced and subsequent searches. i actually found someone with a sl-q1l/dl1 that had the same issue as mine to a lesser degree: vibration on fast forward cuing, but not on slow or reverse. there also appears to be a high incidence of tonearm thumping reported for the sl-7/ql1/dl1 so i may be correlating too much interdependence between the two issues.

i don't think the guide rod is bent as i would expect the same behavior in both directions. i suppose i can check it with a straight edge the next time i have it out of the turntable. i'm starting to wonder if the dry lubrication approach might have something to do with high reports of tonearm thumping. the technics sl-3, sl-6, sl-q6, sl-j33, sl-l25 and kenwood kd-67f linear models in my stable don't thump and all use a lightweight grease on the guide rail. i replaced the graphite with a trace of ptfe impregnated synthetic oil...i'm starting to debate whether to just switch to a lightweight grease or even go back to the dry graphite. unfortunately, i never did any testing before re-lubricating and the graphite i removed was ample and really didn't need replacement.

the thumping i hear isn't that prevalent. at normal listening volumes it's barely perceptible even between tracks or during silent passages. it bothers me that it's there on a turntable with ostensibly the highest build quality around and not on any of the later plasticy linear models. i kinda want this unit to replace the lowly kenwood kd-67f in my setup, but right now it just can't outperform.

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Re: technics sl-dl1 linear turntable repair questions

Post by Spinner45 » 14 Sep 2018 21:30

stanwebber wrote:
fscl wrote:I've also got a non working DL1 that I still need to work on. Sold as a parts unit, it was destroyed / guaranteed to come in more parts in transit by USPS. The base plinth is cracked through and the tonearm drive belt is broken. Will have to get back to you what's on both sides of the worm gear.
this turntable is a tank. how on earth did the aluminum get cracked? what condition did the box come in?

i did some extensive reading of the forum posts you referenced and subsequent searches. i actually found someone with a sl-q1l/dl1 that had the same issue as mine to a lesser degree: vibration on fast forward cuing, but not on slow or reverse. there also appears to be a high incidence of tonearm thumping reported for the sl-7/ql1/dl1 so i may be correlating too much interdependence between the two issues.

i don't think the guide rod is bent as i would expect the same behavior in both directions. i suppose i can check it with a straight edge the next time i have it out of the turntable. i'm starting to wonder if the dry lubrication approach might have something to do with high reports of tonearm thumping. the technics sl-3, sl-6, sl-q6, sl-j33, sl-l25 and kenwood kd-67f linear models in my stable don't thump and all use a lightweight grease on the guide rail. i replaced the graphite with a trace of ptfe impregnated synthetic oil...i'm starting to debate whether to just switch to a lightweight grease or even go back to the dry graphite. unfortunately, i never did any testing before re-lubricating and the graphite i removed was ample and really didn't need replacement.

the thumping i hear isn't that prevalent. at normal listening volumes it's barely perceptible even between tracks or during silent passages. it bothers me that it's there on a turntable with ostensibly the highest build quality around and not on any of the later plasticy linear models. i kinda want this unit to replace the lowly kenwood kd-67f in my setup, but right now it just can't outperform.
Don't under estimate the Kenwood.
Properly serviced and running right, it's got the ability to perform as well as many other high-end record-spinners.

stanwebber
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Re: technics sl-dl1 linear turntable repair questions

Post by stanwebber » 16 Sep 2018 16:35

i want to focus in on the worm drive gear. i wish i had another unit for comparison, but maybe someone else out there has their sl-7/ql1/dl1 apart right now for maintenance and can answer these questions.

1. is there anything else besides a single washer between the brass belt pulley and the stanchion upright?

2. how much side-to-side play is there in the worm drive shaft? is there more than 1 or 2mm of movement side-to-side? barely any?

2. approximately where does the pinwheel (black slotted disc opposite end from pulley) sit in the gap between the optical sensors. is it exactly in the center of the circuit board slot? towards one side or the other? if there is side-to-side play in the shaft where does the pinwheel movement fall in the gap?

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Re: technics sl-dl1 linear turntable repair questions

Post by -ray7 » 26 May 2019 23:26

Ok from my experience. Last 3 hours. Boiled my belt. There's play in the worm screw shaft so it clicks in play ff direction. Mine isn't that bad so let it go. The gimbles must be friction free. Any hang up at all and and it will not work. Loosen the gimble screw that you can get to from the bottom 3/4 turn and lightly lube till tone arm movement is un hindered. Snug gimble screw if needed. Left mine loose. No skips noise for 10 hrs.

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Re: technics sl-dl1 linear turntable repair questions

Post by -ray7 » 27 May 2019 01:07

To be more specific the worm gear shaft sits in a 2 piece cradle. If there is wear on the left side (play) the worm gear will move to the left and that puts the pulley off left from the drive pulley so the belt clunks trying to track on the pulley thats offset too far left. A fix? Let me know i might try to figure it out😀

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Re: technics sl-dl1 linear turntable repair questions

Post by -ray7 » 29 May 2019 03:30

I got 2 sldl1's. 1st problem your gimble screws are too tight or dirty. The tone arm needs to move like floating in space. No friction. Loosen bottom gimble screw and lube. Bout 3/4 turn. I didnt tighten back works good. 2nd worm gear worn on left play side. That moves the worm gear pulley too far left of the motor pulley making the bump of the two pulleys trying to align. I plan on posting a fix for the technics linear thump this weekend.

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Re: technics sl-dl1 linear turntable repair questions

Post by stanwebber » 30 May 2019 17:45

ray7, i'm not following you entirely...

what mechanism part are you referring to when you say gimble?

the worm gear has some left to right movement in the cradle by design when the tonearm changes direction. can you describe the wear you're seeing?

-ray7
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Re: technics sl-dl1 linear turntable repair questions

Post by -ray7 » 31 Aug 2019 21:33

Sorry, the gimble bearings on the tone arm were locked up. So it just sat there and skipped. So loosen and oiled bearings. The bump i tried to fix with shims, but ran so long bumping the parts got worn. So replaced shaft, worm gear and pulley from a slbl3 that the post office ran over with a truck. The brass pully was really worn. Make shure the mounts are snug. Lube and new belt. Still made a little noise. Ran for about 50 hrs then new belt and re lube. It's a lot of work but now no noise at all. Sorry not a easy fix.