Technics SL-5 Series Part 7 - Servo Gain Adjustment
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- Опубликовано: 13 сен 2024
- Setting the servo gain in the tone arm mechanism. Unfortunately the camera didn't get the exact bit where the servo was adjusted, but I do show the procedure for how it was done and what you need to look out for. It actually isn't that difficult, provided you are fairly gentle with your adjustments.
The next video will cover adjusting the speed, and maybe one more to test play a record to ensure it starts and stops in the correct places, and make any adjustments as necessary.
Belt size I used: 22mm diameter x 0,9 or 1mm square.
When you work on these how often are they out of spec and is it noticeable during playback? What should you look for or hear with an out of spec servo? Thanks for the video.
They've always been out of spec, but they often come with a host of other problems. I think if it is working, then leave it be. It's quite a frustrating process if you don't really have any issues. I have to do it, because I take the whole mechanism apart to fix the plastics.
Thank you so much for the series - I have had a long love affair with my SL-5 that I bought in 1981. But I got to this video and reviewed and reviewed it...but you never say what it is that you are testing, or how you know where to test. Respectfully, I don't care about whether or not you made a jig to set it on, but how did you know to attach your testing device to pin 3? How do you know what reading you need on the testing device. why should get a reading of 3.6 microvolts if you move something over? Why is 3.5 ok? The video does not show what you are adjusting. How do you know that? Where is that information? I am a total novice with electronics, I can understand the mechanical stuff, replacing capacitors, cleaning, etc... but I have no idea what you are testing here. Thank you for any help. Feel like my idiot 19 year old self who understood mathematics exceptionally well, until calculus when suddenly I had no idea what anyone was talking about.
It is probably best to view this series in conjunction with a copy of the service manual. Pin 3 is the pin described in the service manual, and I actually hooked up to a different point, but connected directly on the same trace.
It isn't really specified what happens if you are a little bit out on voltage. My advice, get it as close as you can. Going for perfection will drive you nuts and likely not make that much difference.
There might be another standalone video on servo gain that I did before making this series - might be worth having a look at that too.
This might sound like a silly question, but what exactly is the servo gain? Does this affect the amount of pressure as the stylus moves towards the center of the album? Or maybe something else? Near the end of the video, you mentioned that you were not going to mess the spring screw that controls the stylus pressure. If I wanted to adjust the tonearm weight against an album, the platter would have to be stationary while the needle drops down on a scale. This might be a recommended adjustment - maybe for another part?
BTW, I'm going through this entire series several times before I crack open my SL-5. I wish more repair videos were like this in several parts. Thanks you!!!
Servo gain seems to control the advancement of the sled so that you have smooth, continuous playing. All of the SL-5s I have had worked without adjustment, but I set it to the spec as part of the service.
I am pretty sure the height setting would ensure the correct pressure, as there is not much in the way of fine tuning adjustment via a weight as in a traditional tone arm.
Glad you like the way I broke it up. It made sense to me to do it this way, and hopefully makes it easy to get on and do the task you need.
Cool