SL-1500, SL-1300,SL-1350 MK1 schematics

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georgesgiralt
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SL-1500, SL-1300,SL-1350 MK1 schematics

Post by georgesgiralt » 26 Jun 2019 20:52

Hello
I own an SL-150 MK1 and the electrolytic capacitors are going.
The schematics in the library give some values for them but my circuit has sometimes different values from the schematics.
What should I do ? Go for the values on the paper reference or stick to the value in the circuit ?
It is not the cost of the components themselves that bother me it is the work to replace the capacitors and then adjust the circuit. I would like to do the job only once.
So what is your advice ?

Tom_Technics
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Re: SL-1500, SL-1300,SL-1350 MK1 schematics

Post by Tom_Technics » 26 Jun 2019 22:32

I have recapped many of these machines and their relatives. All you need to do is read the sleeves of the ones currently installed and replace them with like for like parts. I can send you a kit for a small fee plus the cost of postage should that be of any use to you. Please PM me if so.

KentT
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Re: SL-1500, SL-1300,SL-1350 MK1 schematics

Post by KentT » 01 Jul 2019 23:28

The SL-1500 manual here in the library, and the supplements will cover your SL-150 Mk I, as it is the armless version of the same turntable.

georgesgiralt
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Re: SL-1500, SL-1300,SL-1350 MK1 schematics

Post by georgesgiralt » 02 Jul 2019 06:50

Hello,
Thank you for your answers.
I've the schematics. My question was about accuracy of it.
In the schematics, Mr Technics indicate they use 6 transistors 2SC666 .... Which are non existent and some form of a joke (666, really ? ). They also specify a strict range of gain on a circuit which does not seem to be so sensitive...
So before buying condensers I would have enjoyed to know if I had to open the SL-150 to read the component value or if I could trust the engineers at Technics on this matter.
As nobody seems to know, I'll go for belt and suspenders and open it up to make my shopping list.
Have a nice bright day

Tom_Technics
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Re: SL-1500, SL-1300,SL-1350 MK1 schematics

Post by Tom_Technics » 02 Jul 2019 10:41

Whilst it is good to replace the old electrolytics, be sure that they are the source of your problem. The speed selector switch of this model should be cleaned via disassembly and with a normal pencil eraser to remove the carbon build up. Both sets of speed controls should also be cleaned with a quality contact cleaner. What you use for the main pitch controls needs to contain a replacement lubricant as the pots will otherwise dry out and the rate of wear will increase.

You haven't actually specified the problem with your turntable so, if you want help, it would be best for you to explain the problem so we can point you in the right direction. Is there an issue with one of the transistors on the board or are you just speculating? The 2SC666 did exist but is no longer available so you will have to find an equivalent. The BC259 may work in it's place but you will have to check as I cannot guarantee.

georgesgiralt
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Re: SL-1500, SL-1300,SL-1350 MK1 schematics

Post by georgesgiralt » 10 Jul 2019 20:26

Hello,
Here am I again.
I've replaced all but one electrolytic condenser. C4 specified as 1µF/25V on the schematics is actually a 2.2 µF/50V on my board. So I let it live it's life until I got a good one.
All the other are far out of tolerance. The loss tangent is well above 20 % for some and their value have highly increased (which means with my cap meter that they are gone, given the way they are measured). And i do not talk about the ESR.... Boy, they're gone !
Now, the speed is more stable than it was. The piano long notes are more precise and well defined.
I'm happy hearing at this turntable.
I bet she will outlive me ;-)
Have a nice day.

Tom_Technics
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Re: SL-1500, SL-1300,SL-1350 MK1 schematics

Post by Tom_Technics » 11 Jul 2019 16:25

Congratulations! I have recapped many of these decks and that 2.2uf is always one of the most out of spec. It's one of the dreaded Matsushita lavender coloured caps that have a reputation for rotting away and even falling off boards. I would advise replacing it asap.

georgesgiralt
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Re: SL-1500, SL-1300,SL-1350 MK1 schematics

Post by georgesgiralt » 11 Jul 2019 20:02

Will do ! but on my turntable, it is a Matsushita all right but it is not like the others. It is red labeled and the sleeve is more whitish than the others. Maybe it has been replaced at some point ?
I have a clock from a car where there are two electrolytic caps. One is so dead that even the connecting wire is missing !
The solder is still OK though. It has a hole in it where the wire was ! So I've seen dead caps before ;-)
At first, I though to replace it with what I found in my drawers just to save another dismantling. But the only 2.2 µF cap I had is a film one and is too big to fit (rated at 630V for tube radio repair). So the 2.2 came back in service and I'll have to open the table again.

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