TurnTable Servicing: Toshiba SR-300C

[Malefoda]

I have no choice: my main is weak with once a 199V for hours... 210 on average. Check that soon with the belt!

[RCruz]

Even 199v is too much for the 110v setting... do not try it !!!

[Malefoda]

Don't be scared I know, I just mean it's already a reduced voltage but noisy main :'(

[RCruz]

Some motors, like the 24 pole premotec, can operate with as low as 70v.... I am using a big TX to reduce from 220 to 110 and some resistros to lower the rest.

The motor looses torque so now I need to hand start the platter but the noise is much lower (vibration induced noise).

In your case, I do not know if it works because the motor is different.

Ricardo

[Malefoda]

Hi Ricardo (and others!)

Any advice to cut & add damping mat, I have a second one for my CDP I bougth with my new iron (the former one died just when I was about to solder the first 100nF SMD...) and have no way to cut it round. I can do it in the inner round, maybe mark the inner circle with a light hammer on the soft black mat, then cut, or the outer but my bitumen mat is too small so I have to do by part. Balance the platter should be a concern also ! And clearance with gears wich I can check by sticking a narrow band.

Left stuff will... dampen my CDP

Matthieu who cannot make things if it's not perfectly clean and in line.

[RCruz]

Your platter is simatrical on the underside so you should cut two "C" shaped strips for the outside and another two for the inside.

Use a compass and a ruler to make a sketch, cut some samples out of paper and place them on the platter for final measurements. Than cut the final strips.

As the strips are simetrical, before glueing, justapose the pairs and trim so the weight is equaly distributed. (You do not want to mess with the platter eq)

Ricardo

[Malefoda]

Hi Ricardo,
I've managed to cut a round piece in the middle and keep the rest for the CDP wich is thge main customer.
Even if it's a over 900g to over 1000g deal it's a +10% of weight.
This is not balanced as it should show some drill or added weight if it was like high-reving engine do have on rotary parts. So I think it's not a problem here.
Enough for now

[RCruz]

Neat work !

Let us know how it sounds.

[Malefoda]

Here I go with the belt. I'm new in the TT world so maybe some of my remarks sound stupid.

The belt is not a belt as I use to see everywhere it's a belt, here it's a rubber band. It must already be pulled larger to fit the TT plate, then again pull it with a real tension to go on the motor idler. I find that strange as it's pulling both motor and plate to each other.
And I also find the moteur is not free spining when off, while the Denon is. So the plate does not free wheel at all.
I did print a Vinyle Engine probe disc... guess what, it's too slow! Enough to make the music dull.
And last but not least, when the Denon is dead silent but a slight motor noise the Thosiba makes a kind of humming, almost the same as the one can be heard in the right channel when amp pot is put full throttle.

I'm ready to open the window to see if it can fly.

edit: I remeber that when I got the Denon in hands the owner try to adjust it and said "it's no more possible to tune it, even full pot to speed adjut the motor is not fast enough." So I opened the bottom lid and adjusted the main big variable resistors to make the fine tuning possible again. In short it was also too slow at least on my main (wich is very nosy, unstable and low).

[Malefoda]

This is the sound of the motor, same loaded or not:
http://www.youtube.com/watch?v=IrlYpiZdle0

... I was dead silent so the clicks or changes of tone are all from the motor itself. There is a problem. And try to take it apart may be its end so the end of this TT also. F!