question about repair

snipped-for-privacy@aol.com ha escrito:

get a q tip, soak in pure alcohol from chemists, gently clean the lens. leave to dry and test-

.B.

Failing this doing the trick, suspect a bad laser.

Arfa

This is like saying: "If your car won't start, check the air filter and if its clean, suspect a the engine needs replacing." :)

See the CD repair guide on startup problems.

--- sam | Sci.Electronics.Repair FAQ:

Repair | Main Table of Contents:

+Lasers | Sam's Laser FAQ: | Mirror Sites:

Important: Anything sent to the email address in the message header above is ignored unless my full name AND either lasers or electronics is included in the subject line. Or, you can contact me via the Feedback Form in the FAQs.

Sorry Sam. Normally, I respect your input, but that statement, in view of the basic symptom and long experience, which I know you have also, is pure nonsense. You know as well as I do, that if a Sony is suffering from failing to read a disc, the first most likely cause is a dirty laser, as "b" suggested, followed by a defective laser. If you know this model, you will be aware that it employs a KSS240A laser which, in view of its age, is the most likely problem, after it being dirty. For sure, there are other possibilities, but if the OP is not experienced enough to have first tried properly cleaning the laser, or suspected it to be faulty before enquiring on here, it is unlikely that he will understand the more technical reasons that the player might not be working.

I stand by my original contention that if the cleaning the laser does not produce at least a degree of fix to the problem, then the next most likely suspect, is the laser itself.

Arfa

I'll happily defer to your experience which is no doubt orders of magnitude more than mine with specific model equipment.

What I would suggest is next time, to include a summary of what you wrote above so that everyone else can share in it. :) Since, it may not be true in general.

--- sam | Sci.Electronics.Repair FAQ:

Repair | Main Table of Contents:

+Lasers | Sam's Laser FAQ: | Mirror Sites:

Important: Anything sent to the email address in the message header above is ignored unless my full name AND either lasers or electronics is included in the subject line. Or, you can contact me via the Feedback Form in the FAQs.

Sam

Ok Sam, I can live with that. I just felt that as defective lasers are the most common cause of virtually any manufacturer's equipment failing to read discs, probably by a factor of 5 to 1 or more over any more complex problem, that in this case, a longer answer was not needed, any more than " b's " one regarding cleaning. Had I have felt that it needed more explanation, I would have given it. That was why I was surprised at your response when I suggested a likely single component ... Have a good 'un d;~)

Arfa

Has it really gotten that bad? I don't think it was like that 10 years ago, was it? There seemed to be many other causes higher up than bad lasers.

--- sam | Sci.Electronics.Repair FAQ:

Repair | Main Table of Contents:

+Lasers | Sam's Laser FAQ: | Mirror Sites:

Important: Anything sent to the email address in the message header above is ignored unless my full name AND either lasers or electronics is included in the subject line. Or, you can contact me via the Feedback Form in the FAQs.

Dont use alcohol to clean the eye lens . Use windex .

I hit the send button to soon .

After cleaning the lens with windex and that does not work you could try to unplug the wire going to the laser and plug it back in . Sometimes this works .

Other causes .. possible bad disk motor , bad laser or wire strip going to it ,, belt slipping .

You failed to mention what kind of disc.

Sam is correct. Let's see, the player does not detect CDs so check the lense for dust? It could be a bad laser? Not even close! CD changers generally have sensors to tell them which slots have disks in them. I'd check those sensors first. Also the change/loading mechanism could have sensor switch problems.

DaveL

Sam, or indeed you, *may* be correct - it depends on what exactly the OP means by the player " failing to detect a disc ". In my experience, this is normal-speak for the player not extracting a TOC from a disc, maybe after a spin-up, maybe not even getting that far. It is very very rare for a player that has separate disc detection, to fail to sense that a disc is on the carousel at any particular position. Many players do not have separate disc detection sensors, relying on the laser to find something when it initiates a focus search. This particular player does use separate optical sensors for both disc and carousel position detection. However, I can't remember ever having a problem with one failing to sense discs on the carousel.

Having repaired many of these, I would fire the same statement of " not even close ", back at you. In my experience, the most common playing problem on these is due to a defective ( or just plain dusty ) KSS240A, and the liklihood of any sensors being at fault is slim at best. I have had the laser flexiprint go bad, and that usually results in failure of the focus motor to operate, as the tracks that normally break are the ones that connect to there. This is easily spotted by watching to see if the lens goes up and down ( having first fooled the sensor into thinking that there is a disc in place, of course ...) Very often, a poke of the flexiprint at that point in time, will cause the tracks to momentarily remake, and the lens will move.

And to Sam, yes, I would say that the situation is that bad now. The quality of the 'standard' Sony KSS series lasers, fitted to many manufacturer's products, seems to have gone down and down over the years, and I change many of them - often in kit that's still within the warranty period, which is often about the only time that it's financially viable to do it. The latest Sony offering in the laser stakes, is not even replaceable. The flexiprint is solder-attached at both ends, so the whole assembly has to be replaced, complete with the servo / amp pcb, which also is not really servicable, as the IC is one of those calculator style " ball of snot " jobs, that has no visible pins for measuring on.

Arfa

Hey Afra,

You may have me there. I've only repaired two CD changers. One Yamaha had a hairline crack on the stepper motor gear that caused it to skip intermittently. One Denon did have bad tray sensor switches. It had a hard time loading disks because of it.

But my point was more to do with the way some things are blanketly diagnosed. I have much more tape machine background. I don't know how many times a lay person would hand me a bad tape machine and tell me it probably just needs the heads cleaned. I'd be like "sure I'll clean the heads for you. How about I fix it after that?"

DaveL

People don't like to feel like they are out of their depth. Cliff Claven wasn't just a character on Cheers.

Ok Dave, fair enough. I tend to pitch replies at the level of expertise that I perceive the poster to have in the field. Anyone who knows me on here would, I'm sure, back me up that I am never one to issue a " blanket fix " statement. I always try to offer considered and practical advice on specific problems that I know on specific equipment, or if I am offering more general advice, it will be based on similar problems that I've had over the 35 or so years that I've been mending this stuff, and the measurements and observations that are most likely to get you to a fix. I was only brief on this one, because that was all that I felt I needed to add to "b's" originally brief, and eminently valid response to this problem on this particular model.

Arfa

I remember there were some Sony models (I think) where the speed of the motor that rotated the corousel would drift with time and then the player wouldn't even recognize that there was a disc in any position. A resistor/pot fixed that.

--- sam | Sci.Electronics.Repair FAQ:

Repair | Main Table of Contents:

+Lasers | Sam's Laser FAQ: | Mirror Sites:

Important: Anything sent to the email address in the message header above is ignored unless my full name AND either lasers or electronics is included in the subject line. Or, you can contact me via the Feedback Form in the FAQs.

Also on these Sony models the inside limit switch can be flaky or inoperative. The disc just spins and does nothing else 'til the limit switch hits.

MarkZ.

Ken, why dont you like the alcohol? My experience, Windex is liable to leave residue. Thanks...