Strange KSS-151A failure

[Mike P]

I recently acquired a Sony 227ESD CDP from Germany via eBay.

Although the player initially worked it now refuses to track discs most of the time.

I've been pulling my hair out over the last couple of weeks trying to diagnose the problem and tonight after removing and examining the transport carefully I finally found the problem.....and it's not good news.

The KSS-151A uses a linear motor for the tracking and I've found that the plastic guide rails are cracked/fractured in several places. As the optical pick-up unit tries to slide of this rails it catches on the cracks and and prevents the laser from tracking properly.

In the photos below you can just see the fracture lines.





I wonder what has caused this? Ageing of the plastic? Mechanical damage in transit? The wrong lubricant? Has anyone seen this problem before?

If anyone has a KSS-151A with a dead laser they would let me have/buy for parts I'd be very grateful.

 

[martin clark]

It could just be residual stress / loss of plasticiser over the years in the moulding.

If it is the slight step at the crack that stops the servo advancing smoothly, I would be very tempted to use a very fine/small file to turn each crack into a V-notch & smooth the transition, to give the thing a fighting chance to ride over meanwhile. Lens focus is a separate issue and will compensate for such small changes absolute rail height.

Good luck with the search for a suitable donor.

 

[Mike P]

I had the same thought about trying to smooth the rails. If I can't track down a donor unit I may as well give it a try. The things dead anyway so I don't have much to lose. Pity as it sounded fantastic when it briefly worked.

 

[graystoke4]

can you super glue first then file down to level it off might work !!!

 

[Dowser]

Epoxy resin or at least araldite would be better than superglue - I'd make the V as per Martin, but then sand it down perfectly flat after filling the crack...lots of work though

 

[Mike P]

Thanks for the replies folks. It seems we're all thinking along the same lines. I might have a stab at dismantling it later today.

I wonder if the higher spec KSS-190A has the same plastic guide rails or if they're all metal?

 

[Mike P]

Wish me luck!

 

[stevec67]

That looks exciting, I hope you made notes of how it all goes back together. I second suggestions that you should glue up the cracks with epoxy, I've used the stuff twice today to hold back compressed air and it's working a treat.

 

[Mike P]

Bloody hell it actually WORKED! I filled in the cracks with 2 part expoxy (araldite) and then when the glue was still slightly soft used a razor blade as a plane to shave the area flat. I then followed with 800 then 2500 grit wet&dry paper until completely smooth.

I haven't been able to listen to the Sony for a while....flippin' eck it sounds glorious.

 

[Dowser]

Nice one - bodge of the month award