mzeitlin3348
See it and Believe
Will the SL-D3 motor control board replace a SL-D2 control board? They look identical.
Technics SL-D2 vs SL-D3 motor control boards
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mzeitlin3348
See it and Believe
mzeitlin3348
See it and Believe
I have the service manual. I re-capped the board, re-soldered any suspecting contact. Changed out some high wattage resistors and cleaned the pots/switches. No good. Speed lock is still lost.
I think its in the IC chip, but many tell me these chips are bullet proof. I may just re-solder the chip too in case it's a contact issue I didn't see.
I love the turntable, but if it can't spin properly, it's useless. I am the original owner back in the 70's - always took care of it. It's just age - like most of us.
mzeitlin3348
See it and Believe
Thanks - I thought as much when I compared parts. Just a few differences like the D2 uses AN630U and the D3 is just AN630. I have no idea the difference, but it probably doesn't matter since I would be replacing the whole board.
I am sad I coudn't fix my original board with a cap overhaul. Frustrating that for 90% of the people who have these TT's all they had to do was either clean the pots or re-cap. Me ... not so lucky.
(but I am going to try one more thing .... remove all solder from the IC chip pins and then re-flow new solder. especially pins 1,23,24 We'll see.)
I am sad I coudn't fix my original board with a cap overhaul. Frustrating that for 90% of the people who have these TT's all they had to do was either clean the pots or re-cap. Me ... not so lucky.
(but I am going to try one more thing .... remove all solder from the IC chip pins and then re-flow new solder. especially pins 1,23,24 We'll see.)
mzeitlin3348
See it and Believe
I just bought a board on ebay (SL-D3) ... so no need to tear into it just yet). I am also going to re-flow the AN630U chip leads just on a hunch.
Thanks!
mzeitlin3348
See it and Believe
Update: I re-soldered key pins on the AN630U IC chip as well as other pins around the board tied to the speed lock circuits.
No change. Platter will spin at correct speed for 20 or so minutes then lose speed lock as before.
The problem is likely inside the chip so that when it warms up something goes open loop on the speed. I had hoped to fix this board - seemed like such a simple thing to accomplish.
I have to decide if I should re-cap the new board with the caps I used on this one or just plug it in as is and see how it goes.
No change. Platter will spin at correct speed for 20 or so minutes then lose speed lock as before.
The problem is likely inside the chip so that when it warms up something goes open loop on the speed. I had hoped to fix this board - seemed like such a simple thing to accomplish.
I have to decide if I should re-cap the new board with the caps I used on this one or just plug it in as is and see how it goes.
mzeitlin3348
See it and Believe
Here's an interesting update ...
I managed to support the turntable above me with the bottom cover removed. I started the unit and the platter spun up to speed and locked in.
After 20 minutes speed lock was lost as expected - but what I noticed this time with the bottom off is that I could hear a very faint pulsating click/thump sound coming from somewhere a few seconds before the speed lock was lost. The pulsations matched the strobe and sped up as the platter lost speed control (and sped up).
What part could do that? Caps? IC chip?
It's very faint and definitely tied to when speed lock is lost. If I shut off the turntable for a few seconds and re-start - there is no sound whatsoever - silent. but as speed lock is lost, the click/thump sound starts up. It could be a sort of popping sound but ever so slightly noticeable. Only by having the bottom off could I hear it.
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mzeitlin3348
See it and Believe
Also, when I measure transistor voltages - I noted on s1846Q - a base (B) voltage of 21.53 . the schematic calls for 22.2
Is that important/significant?
Is that important/significant?
Hi..this is Gazza from Perth/Australia. I have a SL1700 with exactly the same issue and suspecting the IC AN630U after cleaning pots, replacing 6 caps and 2 transistors. My motor speeds up after unit warms up after playing 2 record...generally happens on the 3rd record played in succession. I've also put this motor in my SL1600 as I have 2 TT's..motor works fine ...no speed issues.
I'm interested to know what your outcome was after replacing boards. I'm contemplating buying this IC from AliBaba as it is only a few bucks. On the SL1700 it is not possible to take the bottom off and trouble shoot so I have to go by trial and error .
Look forward to hearing from you
I'm interested to know what your outcome was after replacing boards. I'm contemplating buying this IC from AliBaba as it is only a few bucks. On the SL1700 it is not possible to take the bottom off and trouble shoot so I have to go by trial and error .
Look forward to hearing from you
mzeitlin3348
See it and Believe
Hi Gazza,
Been to Perth - fabulous city - especially by the beach and up in the hills!
I ended up buying a 'used' board off ebay. Spent ~20 (USD) - recapped the board - problem solved. It has been running flawlessly since. I am convinced it was my original IC as well. Not sure you can buy them anywhere.
Thanks..I agree, Perth is great. Haven't been to Houston but did the US East coast (NYC, Boston, DC ) Canada (Montreal & Toronto)..and Detroit, all in 11 days when my girlfriend did the NY Marathon in 2017. Will do the rest of the US one day.
I have a feeling TT was faulty when I bought it but as I never played more than one record at a time I wouldn't have noticed issue. Only when my 1600 had an issue with the tone arm that I started using the 1700 more often. Now I appear to have managed to have repaired the 1600 tonearm. Previous owner seems to have sprayed something into the tonearm bearings..or oiled it.
Plenty more opportunity in the US to buy old parts like you've done, but here we either have to buy new IC's from China hoping it will work or risk buying an old TT with the same issue. Either way , I think it's worth risking it as these TT's deserve to be resurrected.
Thanks for your response and assistance
I have a feeling TT was faulty when I bought it but as I never played more than one record at a time I wouldn't have noticed issue. Only when my 1600 had an issue with the tone arm that I started using the 1700 more often. Now I appear to have managed to have repaired the 1600 tonearm. Previous owner seems to have sprayed something into the tonearm bearings..or oiled it.
Plenty more opportunity in the US to buy old parts like you've done, but here we either have to buy new IC's from China hoping it will work or risk buying an old TT with the same issue. Either way , I think it's worth risking it as these TT's deserve to be resurrected.
Thanks for your response and assistance
