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**LvR** · 9 August 2002, 02:27

If you do get the motor as loose part, make sure that you also get a new "spindle platter" (the goody that sits at the end of the shaft on wich the cd is clamped). Also ask about an allignment jig.

Around here they dont supply the motor as a sparepart - you have to replace the complete spindle tray that was pre-alligned in the factory.

Current consumption is the best way to determine health in my experience - about 20mA at 4.5V no-load - anything way off from that normally indicates hassles to come.

**Fat Tone** · 9 August 2002, 03:14

Thanks for the info LvR. I'm a bit nervous about taking it further apart now. What do I need to align? It looks like I just need to undo four a/v mounting posts and the pcb/motor assembly should come away. The spindle platter just 'pokes' through a hole.
Fortunately my local RadioShack agent seems friendly and will try to source the parts for me. I haven't found a single online supplier of these motors in the uk.

Cheers

Tony.

**LvR** · 9 August 2002, 04:18

The laser is mounted on a sled that can move along 3 axis within the "optical block". The movement of the laser in a vertical direction is severely limited because of design to around 2 mm - if you end up with a spindle platter sitting too low or too high on the motor shaft, you will not be able to get the laser tracking servos to work reliably, and disks that is not perfectly "flat" will not be played without problems - the distance between the laser lens and the cd surface needs to be kept constant, and with a spindle platter that sits either too high or too low, you will find the laser "hight" cannot be adjusted far enough in order to compensate for a wonky disk.

I have further also found the lasers on the Sony units to be pathetic little buggers, that can also cause the same symptoms you are describing. Watch out in particular for units off the KSS240A,KSS213, and KSS210 flavours.

**Fat Tone** · 9 August 2002, 04:40

Thanks again. Silly old me was assuming that the shaft would be exactly the right length for mid-focus distance and that the splindle platter would just pop on top.

As it turns out, I may not have to change it after all. It seems his symptom, according to his wife, (dont you hate 2nd hand stories - the way he told me originally I thought it was dead), was "the CD deck was jumping from track to track unpredictably in midplay" and he has admitted to never having cleaned the lense. This hifi has a hinged glass lid with quite a large air-gap around the edge, and the lense is now clean. My guess is that the shop cleaned the dirty lense and was planning to rip him off to the tune of £90. I'll see if I can replicate his fault at all before going any further.

BTW, www.bullock-bros.com are offering the motor ONLY for £25+£3.99p+p, which seems somewhae steep as I have seen them on US web sites for $2.49!

I'll check what laser assembly it is too.

Thanks again.

Tony.

**Greebe** · 9 August 2002, 05:07

eYup eYup eYup, good advise there LvR

**Greebe** · 9 August 2002, 05:12

TA if you clean the lens be sure to be very careful and get both sides. How many times I've see very nice CD players go belly up because of dirty air (read: smokers) contaminating it. You will also need to adjust the dither signal if it has an adjustment (some of the newer models don't uggg)

**LvR** · 9 August 2002, 05:14

For what its worth - I had a look my service database:

Last 9 years saw 167 Sony CD combo units - only 4 of those required spindle motors (1 was seized solid after a Coke spill, and 3 with bent spindles due to ?????????????) - the rest with CD playing problems all required lasers of the flavours I mentioned if a cleanup could not get them going.

**Fat Tone** · 9 August 2002, 05:32

Originally posted by LvR
...1 was seized solid after a Coke spill...

Yep - that white powder can really cake things up!

Thanks again for all the tips. Any advice on if I should be seeing the DC resistance change whilst rotating the spindle? I guess moving the rotor could be inducing a current that messes with my readings?

T.

**Greebe** · 9 August 2002, 05:39

Any advice on if I should be seeing the DC resistance change whilst rotating the spindle?

Yes this is normal

I guess moving the rotor could be inducing a current that messes with my readings?

You got that right

**Fat Tone** · 9 August 2002, 06:34

Originally posted by LvR
I have further also found the lasers on the Sony units to be pathetic little buggers, that can also cause the same symptoms you are describing. Watch out in particular for units off the KSS240A,KSS213, and KSS210 flavours.

Oh Great! it's a KSS213B

We'll see what several hours playing brings...

T.

**Fat Tone** · 9 August 2002, 08:22

I have it back together and playing no-probs atm. However, beraing in mind Lawrence said 3 motors had bent spindles, what is the maximum vertical displacement I should be seeing at the edge of a disk? It's very obvious on this open contstruction!

Cheers

T.

**Greebe** · 9 August 2002, 08:35

it's extremely small, you would need a eccentricity guage to measure it.

I doubt this would be neccessary to have (and slightly costly)... just bend til you see a minimum wobble

**Fat Tone** · 9 August 2002, 08:43

I'm seeing about 1/2 a disk thickness atm

I think it was more with an old CDR, looks like a combination of warped discs and possibly a bent spindle. I was thinking that if the combination of the two added up to more vertical displacement than the focussing coils allow it could lead to the problems experienced.

T.

**LvR** · 9 August 2002, 10:26

What you are seeing there I would think is normal, and unless you can see the spindle wobble forget about it.

What more often than not happens is that the spindle platter with its sorta sticky surface (to prevent disk slippage when clamped) collects small bits of dirt on its surface - the result is that the disk is not always clamped absalutely horizontal as intended.

Now - close to the centre of the disk that is no problem - but - lets say you have a piece of rubbish sitting on the platter about half a mm thick - close to the centre of the disk the relative vertical displacement from absalutely horizontal is about 1/2 mm and the laser servo can deal with that easily - but - as you move towards the edge of the disk you will find a linear increase in the deviation from horizontal and may very well end up with a vertical displacement of around 2 or 3 mm closer to the edge of the disk. As long as the displacement falls within the lasers ability to move - no problem.

I have seen seriously warped disks playing ok under those conditions, but it did require some meticulous setting up of the servos. ( I cant remember the last time I say a perfectly flat disk - or a deck that was able to clamp one so that it seemed to be when rotating!)

The KSS213 laser is most likely the most unreliable one of the lot in my experience, but then again, it is also way cheaper than the KSS240 if you have to replace it - somewhere around 1/3 the price in my neck of the woods.

Hope your laser hangs in there whan it gets hot.

Suggestion for a good and crude reliability test:

Get a disk that is filled to the brim with music. Select the last track on the disk, and start it playing in repeat mode (Servos getting a real workout here!). Leave it running on the bench overnight - next morning over breakfast it must still be playing without complaining!

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