SP-15 What to do?

[JPK]

Hi,
I picked up a SP-15 and plan to make a 2 arm plinth. Before making the plinth, what PM should I do? Should I remove bearing / spindle to clean and re-lube? While the bearing feels good, no wobble etc. there is a small amount of vertical play if I pull it up and down, less than a 1/8 inch (Less than 3 mm) I would have to measure, but is this typical?

If I hold the start / stop button down the display changes from 33 to 15 is this typical?

I added a couple of drops of oil and all three speeds seem very stable at xx.oo with a strobe disc.

There is a very faint smell of warm electronics with my nose against the vent screen. Is this typical? Or what should I be looking for.


I think this would be a fun table. But prefer to do a tune-up now and avoid surprises later.

Thanks,

Joe

[phonomac]

Hello Joe,
The vertical movement on the spindle is normal, so as long as the bearing feels smooth and snug in rotation just a few drops of Technics spindle oil (available from most DJ supply houses, and in the US from KABUSA.) should do it. Edit: I see you've done the oil.

The start/stop switch behaviour does not seem normal, mine doesn't do that so I think some work may be needed there. (See below)

Effectively there is a switch mode power supply (ala wall-wart) under the vent screen, so you are probably smelling the combination of some heat and high voltage. (By the way I assume that you are checking this after switching off - it isn't good for the motor system to be powered up for long without the platter in place.)

When I got mine it sounded good, but not hugely better than my SL150 MkII. So I set out to do the adjustments in the service manual (available here on VE) and after unscrambling the errors in the service manual I found that I couldn't achieve the specified settings. I then replaced the electrolytic capacitors (only 2 actually measured really bad) and set the adjustments. Now we are hearing some good sounds . I suspect that the electrolytics were causing poor torque, which is the main feature of the SP-15 relative to the SL150 MkII.

If you can do this yourself, or have it done at a reasonable price (for you the caps should be less than $20) I think it would be well worthwhile, and may also take care of the strange speed read-out.

Hope this helps

regards

Angus

[JPK]

Thanks Angus,

I was afraid I would be replacing the caps. Is there any preferred brand or series?

What errors did you find in the manual?

The manual shows propping it up and dropping the boards down. I wonder why they don't want it turned upside down?

What are you using for a plinth? Some I've seen are open underneath and some are closed. Any thoughts or preferences?

Thanks,
Joe

[phonomac]

Hello Joe,
When I recap equipment then for general purpose (ie not signal path) electrolytics it is hard to beat Panasonic FC or FM series caps, and those are what I used on the SP-15. The only exception was the 100uF, 250V C4 in the power section, where I just had to use what I could get. In truth the original C4 measured fine so that was more insurance than anything.

The manual says to check the standard voltages at TP18. Then in the next step it says check the waveform at TP18. TP18 is an ac waveform which is about 7.5V pk-pk, at least 0.5V above ground. So it cannot ever be 2.1V dc which is what is specified for one of the standard voltages. The correct test point for standard voltages is TP22.

You need to keep the turntable upright because all of these voltages and waveforms are checked with the platter installed and spinning.

At the moment I have mine in a two layer Baltic Birch ply plinth, 1.5" thick, so open at the bottom. That was just for speed in getting it up and running but it still sounds pretty good. Next step will be to try a three-layer ply, closed on the bottom for comparison.

regards

Angus

[JPK]

Thanks Angus,

I appreciate your experience.
I'll let you know how it turns out.

Joe