Sl-1710 Mkii Repair Of Cueing And Auto Return

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Head Tomcat
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Thanks!

Post by Head Tomcat » 22 Jul 2009 01:22

I am heading out of town on business early tomorrow morning..and will get started this coming weekend on the 1710 MkII.

Many thanks! Who would have thought that a wonderful turntable I bought as a soldier in Germany in 1980 would have such great support these days...almost 30 years later?!

The Tom

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Post by carlosfm » 24 Jul 2009 09:18

analogaudio wrote:It is true that the Technics TTs use ICs, some unobtainable, however the arm motor drive for the 1600Mk2 and 1700mk2 use your basic low power transistor 2SD638 and 2SB643 for which equivalents can be found that do not degrade performance. In some cases original parts are available.
Well the "performance" is not really important, it would be enough that arm cueing would function reliably. :D
You are right that on the arm drive PCB there are only transistors.
Those can be replaced by equivalents.
But I suspect IC402 (SVIM53217P) may be faulty too.

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Post by analogaudio » 24 Jul 2009 22:45

Carlos

I don't find IC402 in the 1700mk2 service manual, maybe I have overlooked it or are you referring to another model?

I have a 1700mk2 on the bench that has a malfunctioning start sequence, it runs when the arm is brought back and will stop only on being moved out and in again, perfectly logical but the wrong logic! Some figuring to be done (on a good day).

By the way there is a carlosfm at the diyhifi forum where I post as tedr, I've been doing a CD DAC project with Jocko's help, are you the same guy? Couldn't be two in Lisbon could there?

Ted

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Post by analogaudio » 25 Jul 2009 00:42

Tom

I have been troubleshooting a 1700mk2 arm drive this week and I have a tip for you. The arm raise hardware of the 1600mk2 and 1700mk2 is the same except for a few small differences. I also have 1600mk2 and the service manual for the 1600mk2 has a three page illustrated technical description of the arm raise and swing mechanism, this is entirely missing from the 1700mk2 service manual which I also have. It makes a BIG difference having the 1600mk2 information to study.

And you are in luck, the forum library has a 1600mk2 service manual for free download. In the Library select Technics and go to 1600 and click on it and scroll down to see the list of links.

Ted

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Got it!

Post by Head Tomcat » 25 Jul 2009 18:40

Ted,

Many thanks for this information...got in at midnight last night and will be working in the 1710 MKII this entire weekend.

The Tom

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Some progress....then nothing.

Post by Head Tomcat » 26 Jul 2009 03:46

Ted,

I followed your excellent suggestion about the 1600-series service manual having the necessary information to take my 1710 MkII unit apart...and I followed it as printed and got it apart with no problem.

I determined the arm assembly is mechanically fine as the white gears are still in perfect condition, the entire arm lift assembly works when I spin the gears...and nothing is cracked or out of place.

I took the cueing switch apart and all seemed to be in order there, too. You could hear a nice "click" when you pushed the switch button which is mounted to the small PC board.

Putting it all back together was not an issue....everything dropped into place. The issue was when I powered it up...and the platter motor no longer worked!

When the power button is pressed "on" the stylus-illuminator lamp will light up as usual. However, nothing else such as the platter drive motor or the strobe illuminator prism will work.

My thought for this sudden and unexpected failure was when I pulled the two power wires out of the power transformer board (as called for in the service manual) they were actually soldered to the board. This soldering was done on the backside of the board so I could not see it. Since the manual said to pull them out of the board I assumed that on the backside was some sort of mechanism which allowed them to be removed/inserted for service.

Did I screw up by following the service manual when pulling out the two power wires (light blue and dark blue in color, going to AC 1/2 position on the board) and not realize they were actually soldered in place and thus not intended to be readily removable?

I am reasonably sure...given the twisting/turning I had to do to get them out...they were soldered on the backside. If so, this means I no longer have power to the PC board and thus the direct drive platter motor and stylus illuminator cannot receiver power.

Your thoughts? Thanks!

The Tom

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Post by analogaudio » 27 Jul 2009 00:30

The 1600mk2 and 1700mk2 that I have seen there are two light gauge blue AC wires that attach to the central power board these are terminated using wire wrap method. It is OK to solder these back in place after unwrapping them, I cut off the excess bare wire and solder to the pin.

Anyway it may be that the ones you are describing are different but either way resoldering is OK.

Ted

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Post by carlosfm » 27 Jul 2009 16:29

analogaudio wrote:Carlos

I don't find IC402 in the 1700mk2 service manual, maybe I have overlooked it or are you referring to another model?
Yes, I was refering to the 1600/1610 MKII, which is what I have. I thought the 1700MKII would be very similar, probably there are differences in the arm drive circuit.
Or probably it just has a different designation on the 1700MKII service manual.
analogaudio wrote:By the way there is a carlosfm at the diyhifi forum where I post as tedr, I've been doing a CD DAC project with Jocko's help, are you the same guy? Couldn't be two in Lisbon could there?

Ted
Yes, it's me, Ted.
It's a small world.
My avatar at diyhifi.org is the same as here, but now you can't see it. We have updated the forum software for the latest release and now the avatars don't show up. A software bug...

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Post by analogaudio » 28 Jul 2009 00:48

Carlos hi,
I found IC402 but the function is not familiar, a logic buffer it seems, and
yes there is a different arm drive board in the 1700mk2, I have both service manuals and both TTs. The 1800mk2 is different again, a really cut down front pcb for the speed switches and lamp and that's it, no arm board at all, they clearly didn't mind handling lots of different boards. I am also impressed with the great variety of injection moulded parts in these TTs, beginning with the cover the platter and the base, they made a really BIG investment in tooling these TTs for what seems to have been a short production life, except for the 1200mk2 of course which must set some kind of record I think.

Ted

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Post by analogaudio » 28 Jul 2009 16:11

Tom, a further thought regarding the CUE switch, see if you can verify the electrical function of that switch using a resistance meter. The switch can age (it may have spent most of the past 30 years not operating and oxidation can occur). On my units the CUE switch is connected by a pair of yellow wires, you want a low resistance (less than 10 ohms) from one wire to the other with your finger on the switch.

Regarding loss of power to the main drive board it should come back to life when reconnected. On the drive board AC 1 and 2 are the main power connection points and it won't matter which way round they are connected.

Ted

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Ted..sent you a PM several days ago...

Post by Head Tomcat » 10 Aug 2009 23:41

...was hoping (since it was my first PM on this forum) that you got it.

The Tom

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Ted/Analogaudio Repaired It!

Post by Head Tomcat » 21 Sep 2009 21:47

All,

I want to formally go on record that Ted/Analogaudio was a most gracious host this past weekend when I came to his house and dropped off my beloved SL1710 MkII for surgery. More importantly, he absolutely repaired it and now it is spinning vinyl like it did when I bought it in 1980!

With a replacement of the OEM motor and controller board, he got it working perfectly well. Further, when I came to his house on Sunday to pick it up...it was already plugged into his stereo and had a record cued up and ready to run. On a humorous note, my 17-year old son was amazed as he had literally never seen a record get played before. We had a most interesting discussion in the car on how the needle transmits sound to the speakers.

Once again, this forum (and Ted!) has made me one of the happiest guys in the US.

Thanks Ted!

Your Friend,
Bob

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Post by analogaudio » 27 Sep 2009 00:34

Thank you for the kind words. The arm motor had failed, it measured low resistance, the only option was to replace it with one from another machine, which I have. The arm motor drive board also had to be replaced for normal operation to be restored. Since then I have discovered that in this case the original motor was repairable, cleaning the commutator restored normal operation.

I have experience now with a number of the 1600mk2, 1700mk2 and 1800mk2, and these machines are built like tanks and it is a pleasure to work on them because they are made to be taken apart and put back together again. The fit and finish of the parts is so good it makes me wonder how they ever made any money on them, the cost of parts could be astronomical. But there again the platter, the arm, the motor and motor chips, are all exactly the same as the current 1200mk2, must be a contender for the longest running production life of any audio component!

Ted

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Re: Sl-1710 Mkii Repair Of Cueing And Auto Return

Post by musicisum » 11 Jan 2020 11:48

Hi there, hope some of the posters with knowledge of this turntable are still posting here. I bought a near mint SL1700mk2 last year and all was running well until the cue function and arm return completely ceased working. I used instructions on the common belt repair to check and did indeed notice a perished belt so was confident that would sort things. This is sadly not to be! The new belt is in and the motor is operational on pushing the cue button, but the motor then runs continuously, turning the white plastic wheel fine, but with no functionality restored. I have to turn the power off to stop the motor running...
I'm not myself that savvy with electronics but a good friend is, though I wondered if someone might be able to let me know where to get the service manuals for this model (and the 1600mk2 if useful) and what I might be able to tell my friend to help him isolate the likely problem.
Any help at all is really appreciated.
I'm half regretting getting this model over the 1210mk2, as I'm wondering if the extra complexity of this unit is going to cost time and money to keep running-versus a little more outlay initially for a 1210mk2 which would be less prone to future problems. Any thoughts on the viability of maintaining these more automated units for the next couple of decades?

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Re: Sl-1710 Mkii Repair Of Cueing And Auto Return

Post by chgc » 12 Jan 2020 03:18

The SL-1600/1700 MK2’s are indeed more complicated than most manual turntables. I suspect that a little repair and maintenance every decade or two will keep them working for another 40 years, but only time will tell. Manuals available for download on this site.