SOLVED
Fix: replaced the laser
Hello Ladies and Gentlemans
I have a Kav-300 Cd player and when putting the cd in, the cd mechanism start spinning the cd and after 5 sec, it stops.
The player hasnt been used for many years and i suspect there are a few bad capacitors.
I tried to find the service manual and i cant find the correct one.
Any help?
Fix: replaced the laser
Hello Ladies and Gentlemans
I have a Kav-300 Cd player and when putting the cd in, the cd mechanism start spinning the cd and after 5 sec, it stops.
The player hasnt been used for many years and i suspect there are a few bad capacitors.
I tried to find the service manual and i cant find the correct one.
Any help?
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You are assuming a bad capacitor without any indication this is the case.
What we know is the laser is getting a focus lock, and the disc is spinning. You haven't told us if the speed is stable, too fast or too slow.
Do not adjust anything, or replace anything yet. You may create additional issues, and waste money in the process.
What does the eye pattern look like? Can you post it please?
What we know is the laser is getting a focus lock, and the disc is spinning. You haven't told us if the speed is stable, too fast or too slow.
Do not adjust anything, or replace anything yet. You may create additional issues, and waste money in the process.
What does the eye pattern look like? Can you post it please?
I had an Bang & Olufsen cd player last week and it did the same. Spinning and stops after 5 sec. I found a website indicating that the caps on the servo board needs to be changed , which i did and it solved the problem, it was only 6 caps, so it was an easy one.
The cd-player were given to me for free so i dont have so much knowledge about age and usage.
An other issue on this player were that the cd eject mechanism didnt worked as the belt were too weak. That been also changed and that part works.
So im guessing the cd player havent been used for several years.
The cd spins normally and i can hear the laser to move but its not reading and it moves away and then cd stop spinning.
I do not have a oscilloscope, allthough i have multimeter but that wont help on the eye pattern.
The cd-player were given to me for free so i dont have so much knowledge about age and usage.
An other issue on this player were that the cd eject mechanism didnt worked as the belt were too weak. That been also changed and that part works.
So im guessing the cd player havent been used for several years.
The cd spins normally and i can hear the laser to move but its not reading and it moves away and then cd stop spinning.
I do not have a oscilloscope, allthough i have multimeter but that wont help on the eye pattern.
Honestly, attempting to service something without the proper tools is a non-starter. The eye pattern tells you so much.
I receive equipment damaged by attempted service extremely often, some destroyed. Because you got something cheap or free isn't an excuse to hack it. It's always a shame when one of two things happen.
I receive equipment damaged by attempted service extremely often, some destroyed. Because you got something cheap or free isn't an excuse to hack it. It's always a shame when one of two things happen.
- Someone spends a lot of time and money on something that was too damaged to repair, or had a serious fault expensive to repair
- Someone damages equipment that could have been repaired normally by a skilled person in the trade.
This cd player should use SONY KSS-240A pick-up. Check whether its lens is stained or fogged, or try to enhance the luminescence of the laser diode. This should be able to confirm whether the KSS-240A is damaged, but this is things you do without an oscilloscope. If you have an oscilloscope, first confirm the eye pattern but you may not be able to see the eye pattern because the pick-up focus fails.
To observe the eye pattern, please use a CRT-type oscilloscope. I am not sure that the digital oscilloscopes on the market can see the eye pattern.
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Gokhann
There is no CD servo circuit in the service manual. What is the number of U402 on the circuit board?
There is no CD servo circuit in the service manual. What is the number of U402 on the circuit board?
I hear some strange mechanisms sounds, it does not sound fluid the mechanism, it seems like some cogwheel or gear is jammed or does not work as should. I bet it is a mechanical problem.
First shot, analogue scope.
Second shot, very expensive digital scope (direct capture).
It took me to get to a Keysight 3000 series 1 GHz scope to get eye patterns I could use. So I always recommend a decent analogue oscilloscope for audio work. I keep my analogue scopes for this reason, although the Keysight operates very well.
Second shot, very expensive digital scope (direct capture).
It took me to get to a Keysight 3000 series 1 GHz scope to get eye patterns I could use. So I always recommend a decent analogue oscilloscope for audio work. I keep my analogue scopes for this reason, although the Keysight operates very well.
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The 2465B is a great oscilloscope. I couldn't afford it when I was young, and now I can't buy one in good condition.
I'd sell mine to someone who knows what it is. It's serviced too. It lived in my rack with the Tek rackmount kit.
Mine is a 2465B CT (frequency counter option). I used to connect a frequency counter to the Y1 output on all scopes. You don't have to with this one.
Mine is a 2465B CT (frequency counter option). I used to connect a frequency counter to the Y1 output on all scopes. You don't have to with this one.
Sorry it took time to get back here.
I couldnt get an analog oscilloscope so i asked a few people and they suggested me to change the laser.
I found one in German my and replaced it and today i have tested it. It worked perfectly.
Thanks for your help
I couldnt get an analog oscilloscope so i asked a few people and they suggested me to change the laser.
I found one in German my and replaced it and today i have tested it. It worked perfectly.
Thanks for your help
I'm glad it worked, however, how can you tell if it is set up correctly?
Changing stuff "just 'cause" is never a great plan. The other thing is you have ero idea of quality without being able to see what is going on.
I still HIGHLY recommend you look at the eye pattern with a scope.
Changing stuff "just 'cause" is never a great plan. The other thing is you have ero idea of quality without being able to see what is going on.
I still HIGHLY recommend you look at the eye pattern with a scope.
Well i cant be sure how correctly that is.
I ordered exactly same model nr of the laser. I didnt adjusted anything so hopefully everything is good as it should be. If i get an oscilloscope, i will try.
I ordered exactly same model nr of the laser. I didnt adjusted anything so hopefully everything is good as it should be. If i get an oscilloscope, i will try.
All I'm going to tell you is that you normally have to set a new laser head up.
In the first years, you even had to set the laser power. These days many servos look after adjustments, so the quality went way down. People no longer looked to see how good the head was. Well, I sure do!
The eye pattern is much like a blood test for a human. It tells you all kinds of things. We used to have access to the C1 and C2 error detection flags (they blocked that), which told us a whole lot more. So if you can find the eye pattern, or RF test point, look at it. These days they often don't label it. THose VAM transports are so bad, they hid this test point (unlabeled). It is the first thing you normally look at. Similarly, the laser power was measured with Philips. They stopped that too. I still check. I reject a ton of transports of this type.
If you don't and it works, it will probably not work much earlier than it should. Best find out now when you can return it. Up to you.
In the first years, you even had to set the laser power. These days many servos look after adjustments, so the quality went way down. People no longer looked to see how good the head was. Well, I sure do!
The eye pattern is much like a blood test for a human. It tells you all kinds of things. We used to have access to the C1 and C2 error detection flags (they blocked that), which told us a whole lot more. So if you can find the eye pattern, or RF test point, look at it. These days they often don't label it. THose VAM transports are so bad, they hid this test point (unlabeled). It is the first thing you normally look at. Similarly, the laser power was measured with Philips. They stopped that too. I still check. I reject a ton of transports of this type.
If you don't and it works, it will probably not work much earlier than it should. Best find out now when you can return it. Up to you.