This is the most in depth video, that I've seen about failed laser units. I've played myself with them too, but I haven't got across a totally dead laser diode. Cheers :)
I used to work in a repair shop, we always looked at them from the side, never had a problem with that. I knew several others in the comsumer electronics repair business, never heard of anyone damaging their eyes but they warned us about it in classes. Anyway use caution, don't look down directly into the lens.
And about adjusting distance lense to the CD and angle, any research in this workfield? - I'm trying to do it after changing the group of induction coil's of lense and magnets, but no success for now. I really need something more ...
Nice video! At the time when you were using an external PD to measure the output of the LD, I was wondering if you were really using a PD of correct wavelength to match the wavelength of the LD. The standard wavelength of laser diodes in CD pickup units is 780 nm, which belongs to the near IR light spectrum. By using the internal PD instead to check the power output of the LD, you can at least be sure that you are using a PD of the correct wavelength when making this test. One could easily be mislead into believing that the LD is malfunctioning when it's actually not when using an external PD of the wrong wavelength. Also, you have to check the datasheet for the external PD you are using to verify whether that particular PD is to be operated in voltaic mode, photo conductive mode, or if it can be configured for both types of operation. When using the internal PD, you can also be mislead if the internal PD so happens to be defective and therefore not giving a response. However, if the internal PD is defective, then you will have to replace the whole LD package anyway so it really doesn't matter. After all, a LD package with a defective PD inside it will make the APC circuit malfunction, meaning that the LD package has to be replaced to repair the problem anyway.
What is first ?Disc spinning and lens light go on or first light goes on and then the disc start spinning??I have problem with my Numark Cdn 88 double cd .Laser light wont go .
Yeah you really shouldn’t look at a laser diode even if it appears dim because it may actually be very bright at a wavelength you can’t see - and it will burn your retina if it’s powerful or focussed. You were putting 100mA through it -I’d consider anything above a few milliamperes dangerous.
@@555-xd1fo They are extremely sensitive to static electricity. From a CD player service manual: "Do not check the laser diode terminals with the probe of a circuit tester or oscilloscope".
great video! Good insight into how these devices work with the tear down. I have a cd player that was working a couple weeks ago. The disc does not spin . I tested the drive motor and the laser diode track motor working independently. Im thinking its maybe the motor driver ic chip that controls both these motors or the laser/photo diodes could be bad.
Laser diodes, which operate in the invisible region have an indicator. Somewhere in the middle is to see a small red point of light. When installed, you can see the point from every angle. So my experience ...
I just pulled a diode from a cdrom and I am wondering how to test it. I have no idea which wires sticking out of are positive, negative, and since I don't have a variable power supply, I was just going to stick a AAA battery on it. What do you think? Stupid Idea? I do have some goggles at least.
If you dont put some kind of resistor between the battery and the diode, the diode will act as a short circuit between the battery terminals and burn out the laser. Look up what the original trim pot setting is on the CD lens, and replicate that. Then use 2 batteries in series to get 3V. You could just try a 4.7K resistor, I am sure that would be fine. you just want some current limiting in there.
You should have used a cheap camera - either a webcam or a cam in an old phone. Good quality cameras have IR filters that block a lot of IR light. The cheaper the better
Laser diodes are extremely sensitive to ESD. You have to wear a strap at all times. If it was banging around in your parts drawer for years, then it probably got killed by ESD.
@@hackwithkrishnansh Electrostatic discharge, electricity discharge at high voltage(but very low current) - typically generated from everyday actions like rubbing clothing materials when moving around.
Hi Chris, Good morning. I'm from Brazil and I'm having a hard time finding the optical unit 12.4 Do you know where I can buy? One more question in the great majority that substitutes or lasts very little time or does not work in media only in originals, has how to help me Best regards Moisés
Hey, thank you for this cool video! I have a quick question: Is there any way you know of to remove the plastic part on top of the other spindle motor, the one that spins the CD? I tried some force but I am scared to break it... Thanks!
+Mama Littlefoot Just in case anybody else tries to exchange a broken spindle motor in a Sony ICF-CD815 CD alarm clock... The machine is made well and you can easily take it apart and put back together without problems. I found a seller of the disc DC motor from Singapore (very nice customer service). My project failed at the last point where I had to detach the plastic spindle platter from the motor shaft. It was MONSTER tight and although I eventually was able to hammer it out (thanks to Eric's tip) , the plastic spindle platter suffered too much, distorted and became too wide on the inside. A crude attempt to fix that with super glue did not work. No idea whether there would be any place to buy a spare spindle platter for the machine, since they discontinued the product. Am a little sad that I could not revive our favorite CD alarm clock... Want to share a great resource for troubleshooting CD players (wish I had any idea how really hard it is to remove the spindle platter): www.repairfaq.org/sam/cdfaq.htm#cdspmotpr
Mr. Eric Wasatonic, ¿may I ask for your opinion, please, kindly on a CD player I own, please? I currently have a Magnavox CDB 650 CD player (purchased new in ~1986) that is not reading discs all the way through. But only the first 4 or so tracks, and only when machine turned on from a cold state. It gets better as it warms up. Following is a better description: The player does not play all tracks on CD. One CD is worse than others. Turning it on from cold, it plays the first 4 tracks just fine. Then, at about the 5th track, an audible (high frequency, but not extremely loud, just louder than normal operation and abnormally there). It will continue to play this way for a few more seconds to 20, 30 , perhaps 1 min more. Then, the whine will increase slightly more (to its max) and then the disc suddenly stop, the head returning to home position, and front panel displaying disc data as when first loaded. As the player warms up with 'play' time, the occurrence (whine & sudden stops) moves out (in tracks). One CD is worse than others with this issue, and the problem ameliorates with 'play' time. That is, plays more consecutive tracks (from the CD's beginning) until commencement of said symptoms. If player is in 'play' long enough, (~1 hr+), nearly the whole CD becomes playable. I don't know if the noise is coming from the focusing coil or the arm motor. (My guess the latter). The spindle motor runs just fine, and I can hear it moving from track-to-track with its normal soft spin/zing noise. And thus I tend to rule that out. I've taken the drive electronics board off, and made static conductivity measmts through the flex connections and it checks out ok (with read head at home position only). (I'm the orig owner, from new, & have not heretofore had the drive electronics/assembly apart). Is there any advice/help you can kindly offer, please? Any help is much appreciated. (I'd like to keep this machine, as I have changed the coupling caps in its output stage, sounds nice, and has a nice keyboard for track selection). Thank you so much, in advance, Mr. Eric Wasatonic. God Bless. tonydecrescentis.
I was going to say bad caps...but it sounds like you already replaced them. Have you used a curve tracer on all the parts? Another thing I was thinking was that the flat cable might have a fracture in it, and when it gets to a certain point it folds in the right way to kill the signal. I had a flat cable on a pocket computer fail. If the cable was at the right angle it would function perfectly, but once it bent at the right location it would cease to function. I have to replace that flat cable with wire wrap wire or magnet wire instead.
Hey I have cpu power supplies and laser diodes but nothing to build the driver outta.. Any ideas on how we can harvest/repurpose the driver not just the diode from the CD burner?(I also have a bunch of CD burner guts an REALLY don't wanna waste/buy new drivers that are right under my nose)
I was gonna ask a silly question but then you answered it at the end. You cannot just change the laser diode but need to replace the whole assembly. The Sony CFD-S70 is notoriously bad for the lasers breaking. I was hoping to fix it but it's not really worth the price of a new assembly.
My CD player has started jumping, skipping and making strange crackle noises, similar noise you’d get with a loose speaker cable. I’ve replaced digital optical cable, my Hifi equipment works fine with other devices, turntable, games consoles etc so must be CD player. Anyone got a clue where I should start looking for the issue before I go out and buy a new player. Thanks in advance👍
What is actualy the cause of "disc error"? In you case is laser fail, but sometimes help the lence cleaning, but not always because there are two more lences under the upper visible focus lence what we are cleaning + prism lence at the bottom where photo laser beam skew 90° up. So there are many surfaces which can colect the dirt and we can clean only the upper focus lence and only front side. Does this laser beam is aging and destroying the plastic structure of lences which become untransparent like the polimer headlamps lences on cars durig the time and the disc is unreadable? Does the laser become weak during the time or it can only be in state working and not working and nothing between this states like transistors or diode? Does anybody knows more about?
The lasers themselves rarely seem to be the cause of disks not reading, it seems to be more commonly caused by dirty/hazy lenses, 'sticky' guide rods(such as from dried out lubrication), and various types of misalignment. There are typically multiple pots to adjust different controls, but tiny changes can throw things way off, and can be very difficult to set properly (at least without an oscilloscope and knowing what it should show)
Outstanding video actually. Easily understood, clear vocabulary and terms, although beyond my current knowledge level in terms and definitions, thats my problem to learn. haha... anyhow, thanks very much!!!!
Yes, it's near-infrared - we can't see beyond certain wavelengths(the 'visible spectrum'). Likewise most remote controls use infrared light that we can't see. Some things like cd lasers aren't visible but can definitely do damage to your eyes! The red light is presumably just to indicate that the laser is operating.
Your Video suggests that even if we could get new Laser Diodes for our C.D. Players we would need to set up the Optics before we could play anything again.This is a bit disappointing as I had hoped for a nice simple high tech equivalent of changing a Gramophone Needle.
I was fooling around with my original xbox and came across the laser disc reader a warning label said if was radioactive. If it's not plugged in is it still radioactive?
No clue. Other than Americium in smoke detectors and X-rays emitted from high voltage rectifier tubes in antique televisions, I don't know of any other radiation from household electronics.
It sounds unlikely that a CD player would be radioactive(as in emitting ionizing radiation), however, it might have a warning about laser radiation, and possibly the warning symbol for laser radiation(a filled circle with alternating shorter and longer lines radiating from it, with one line extending to the edge of the symbol). Of course, the laser would only be on if the device was operating at the time.
Eric Wasatonic There are quite a few radioactive things people may have around, actually, but if we limit it to electronic things, an example may be glow or arc discharge based devices(neon lamps, fluorescent starters, HID lamps etc), which may have thorium 232, promethium 147 or Krypton 85 added to help them reliably ignite. I also seem to remember that some vacuum tubes use thoriated tungsten cathodes/filaments, though, If I recall correctly, it was more common for high power tubes used for transmitters than the ones used in general electronics. Some older instruments and clocks have radioluminescent paint which generally contains radium 226/228, and it is possible to come across it in some electric devices. I would say that any old device or instrument which appears to have or have had glow in the dark paint on it should be checked with a suitable detector before one takes out the screwdriver or gives it to the family's little engineer, just to be safe.
Tiny bit of visible light could be the same as 1 Watt+ of laser light at fex 780nm, you are very stupid to look directly at these no matter how dim the light is!
There is a easy way to test this in the player itself. It’s called a oscilloscope that would be a lot easier. What a crap way to test a cd pickup. Also to test a laser you need a LPM meter to test its output and wavelength. This is not how to test a laser diode. It’s the long way when you can do it quicker.
Well said... It would be like testing a floppy drive by pulling of the read/write head and putting it next to a toroid core with some magnet wire wrapped around it...Ruining the drive alignment in the process. The easy way would be to test before the pre-amplifier and after.
Peter Lamont Well said to you too. Glad you know what your doing. So many bad videos on RUclips showing you diy repair that show you to make things worse. You need special tools to test signals,etc in these devices.
why is there no in depth information on how to diagnose and repair these things...I fucking hate buying new. and this is the most common fault on anything that reads discs. fuck the system
Because they're very difficult to adjust without the proper equipment and training, also has the potential to damage your eyes. I expect there are technical documents that go through all this, but it seems likely they aren't suitable for most people to understand without prior study. I don't think the laser itself is the most common problem though, the most common issues seem to be related to dirty lenses and tracking problems.
Horrible video ! you are teaching "how to test laser ..... '' when you don't have enough knowledge about it yourself ! Some people who are curious and uneducated (enough) might follow and fall into the same mistakes and even get permanently damaged ! The video has been reported ! if you have some decency, remove the video yourself, you should start it with the health hazards and warning ..... and for your own sake, i encourage you to learn about laser safety.
This is the most in depth video, that I've seen about failed laser units. I've played myself with them too, but I haven't got across a totally dead laser diode. Cheers :)
I used to work in a repair shop, we always looked at them from the side, never had a problem with that. I knew several others in the comsumer electronics repair business, never heard of anyone damaging their eyes but they warned us about it in classes.
Anyway use caution, don't look down directly into the lens.
I always wanted to use a laser diode from an old CD drive for some project, but never actually tried. Your tutorial may be very useful.
What do the letters A and I that you drew on the paper mean in 8:00?
'A' stands for Ammeter and 'I' stands for current
1:40 what is the name of these blue and red things that you connected to the diode?
minigrabber
thank you
***** nice ^^
i can put 12v DC and 1.25 A to check CD len?
And about adjusting distance lense to the CD and angle, any research in this workfield? - I'm trying to do it after changing the group of induction coil's of lense and magnets, but no success for now. I really need something more ...
Can we defind the laser diode pinout using multimeter
Nice video! At the time when you were using an external PD to measure the output of the LD, I was wondering if you were really using a PD of correct wavelength to match the wavelength of the LD. The standard wavelength of laser diodes in CD pickup units is 780 nm, which belongs to the near IR light spectrum. By using the internal PD instead to check the power output of the LD, you can at least be sure that you are using a PD of the correct wavelength when making this test. One could easily be mislead into believing that the LD is malfunctioning when it's actually not when using an external PD of the wrong wavelength. Also, you have to check the datasheet for the external PD you are using to verify whether that particular PD is to be operated in voltaic mode, photo conductive mode, or if it can be configured for both types of operation.
When using the internal PD, you can also be mislead if the internal PD so happens to be defective and therefore not giving a response. However, if the internal PD is defective, then you will have to replace the whole LD package anyway so it really doesn't matter. After all, a LD package with a defective PD inside it will make the APC circuit malfunction, meaning that the LD package has to be replaced to repair the problem anyway.
Very fun to disassemble, The other day I played around with the magnetic focus module, which is pretty cool.
That interferance pattern is called Newton's rings.
What is first ?Disc spinning and lens light go on or first light goes on and then the disc start spinning??I have problem with my Numark Cdn 88 double cd .Laser light wont go .
Yeah you really shouldn’t look at a laser diode even if it appears dim because it may actually be very bright at a wavelength you can’t see - and it will burn your retina if it’s powerful or focussed. You were putting 100mA through it -I’d consider anything above a few milliamperes dangerous.
how to defind the laser diode pinout using multimeter
@@555-xd1fo put the multimeter in diode mode, and measure in both directions. It only has two pins.
@@555-xd1fo They are extremely sensitive to static electricity. From a CD player service manual: "Do not check the laser diode terminals with the probe of a circuit tester or oscilloscope".
@@SamiJumppanen oh thanks
great video! Good insight into how these devices work with the tear down. I have a cd player that was working a couple weeks ago. The disc does not spin . I tested the drive motor and the laser diode track motor working independently. Im thinking its maybe the motor driver ic chip that controls both these motors or the laser/photo diodes could be bad.
Laser diodes, which operate in the invisible region have an indicator.
Somewhere in the middle is to see a small red point of light.
When installed, you can see the point from every angle.
So my experience ...
I just pulled a diode from a cdrom and I am wondering how to test it. I have no idea which wires sticking out of are positive, negative, and since I don't have a variable power supply, I was just going to stick a AAA battery on it. What do you think? Stupid Idea? I do have some goggles at least.
read a little abou constant current sources and driving led's. You might want to lookup "variable current source with lm317 "for example.
If you dont put some kind of resistor between the battery and the diode, the diode will act as a short circuit between the battery terminals and burn out the laser. Look up what the original trim pot setting is on the CD lens, and replicate that. Then use 2 batteries in series to get 3V. You could just try a 4.7K resistor, I am sure that would be fine. you just want some current limiting in there.
Adjust the potentiometer just a hair and it seems to help me working on lazers
You should have used a cheap camera - either a webcam or a cam in an old phone. Good quality cameras have IR filters that block a lot of IR light. The cheaper the better
Laser diodes are extremely sensitive to ESD. You have to wear a strap at all times. If it was banging around in your parts drawer for years, then it probably got killed by ESD.
I bet he never put the shorting link on it to protect it either when it wasn't connected to the player.
The Lightning Stalker esd ?? Wht is...it
@@hackwithkrishnansh Electrostatic discharge, electricity discharge at high voltage(but very low current) - typically generated from everyday actions like rubbing clothing materials when moving around.
At the bottom of the lens there is an optical ic , so may tell me little bit about that ic or its datasheet.
can you tell me is bad laser when trow light around lens or its dead?
?
@The Lightning Stalker - Thanks for the tip.
The diamond shape at 2:13 is due to the aperture inside your camcorder.
Actually that whole pattern/shape is because of the pattern of the pixels on the camera's sensor.
That "dim" later could actually be incredibly bright and eye damaging It's just as you said yourself it's barely within what our eyes can pick up.
Hi Chris, Good morning.
I'm from Brazil and I'm having a hard time finding the optical unit 12.4
Do you know where I can buy?
One more question in the great majority that substitutes or lasts very little time or does not work in media only in originals, has how to help me
Best regards
Moisés
Hey, thank you for this cool video! I have a quick question: Is there any way you know of to remove the plastic part on top of the other spindle motor, the one that spins the CD? I tried some force but I am scared to break it... Thanks!
+Mama Littlefoot Support the spindle in a vise or some type of jig, and punch out the motor shaft with a small rod or nail and hammer.
+Eric Wasatonic Thanks you the advice. Really appreciate it :-)
+Mama Littlefoot Just in case anybody else tries to exchange a broken spindle motor in a Sony ICF-CD815 CD alarm clock... The machine is made well and you can easily take it apart and put back together without problems. I found a seller of the disc DC motor from Singapore (very nice customer service). My project failed at the last point where I had to detach the plastic spindle platter from the motor shaft. It was MONSTER tight and although I eventually was able to hammer it out (thanks to Eric's tip) , the plastic spindle platter suffered too much, distorted and became too wide on the inside. A crude attempt to fix that with super glue did not work. No idea whether there would be any place to buy a spare spindle platter for the machine, since they discontinued the product. Am a little sad that I could not revive our favorite CD alarm clock... Want to share a great resource for troubleshooting CD players (wish I had any idea how really hard it is to remove the spindle platter): www.repairfaq.org/sam/cdfaq.htm#cdspmotpr
Mr. Eric Wasatonic, ¿may I ask for your opinion, please, kindly on a CD player I own, please? I currently have a Magnavox CDB 650 CD player (purchased new in ~1986) that is not reading discs all the way through. But only the first 4 or so tracks, and only when machine turned on from a cold state. It gets better as it warms up.
Following is a better description: The player does not play all tracks on CD. One CD is worse than others. Turning it on from cold, it plays the first 4 tracks just fine. Then, at about the 5th track, an audible (high frequency, but not extremely loud, just louder than normal operation and abnormally there). It will continue to play this way for a few more seconds to 20, 30 , perhaps 1 min more. Then, the whine will increase slightly more (to its max) and then the disc suddenly stop, the head returning to home position, and front panel displaying disc data as when first loaded.
As the player warms up with 'play' time, the occurrence (whine & sudden stops) moves out (in tracks). One CD is worse than others with this issue, and the problem ameliorates with 'play' time. That is, plays more consecutive tracks (from the CD's beginning) until commencement of said symptoms. If player is in 'play' long enough, (~1 hr+), nearly the whole CD becomes playable.
I don't know if the noise is coming from the focusing coil or the arm motor. (My guess the latter). The spindle motor runs just fine, and I can hear it moving from track-to-track with its normal soft spin/zing noise. And thus I tend to rule that out. I've taken the drive electronics board off, and made static conductivity measmts through the flex connections and it checks out ok (with read head at home position only). (I'm the orig owner, from new, & have not heretofore had the drive electronics/assembly apart). Is there any advice/help you can kindly offer, please? Any help is much appreciated. (I'd like to keep this machine, as I have changed the coupling caps in its output stage, sounds nice, and has a nice keyboard for track selection). Thank you so much, in advance, Mr. Eric Wasatonic. God Bless. tonydecrescentis.
I was going to say bad caps...but it sounds like you already replaced them. Have you used a curve tracer on all the parts? Another thing I was thinking was that the flat cable might have a fracture in it, and when it gets to a certain point it folds in the right way to kill the signal. I had a flat cable on a pocket computer fail. If the cable was at the right angle it would function perfectly, but once it bent at the right location it would cease to function. I have to replace that flat cable with wire wrap wire or magnet wire instead.
Hey I have cpu power supplies and laser diodes but nothing to build the driver outta.. Any ideas on how we can harvest/repurpose the driver not just the diode from the CD burner?(I also have a bunch of CD burner guts an REALLY don't wanna waste/buy new drivers that are right under my nose)
I was gonna ask a silly question but then you answered it at the end. You cannot just change the laser diode but need to replace the whole assembly. The Sony CFD-S70 is notoriously bad for the lasers breaking. I was hoping to fix it but it's not really worth the price of a new assembly.
Your a professional you know!
My CD player has started jumping, skipping and making strange crackle noises, similar noise you’d get with a loose speaker cable. I’ve replaced digital optical cable, my Hifi equipment works fine with other devices, turntable, games consoles etc so must be CD player. Anyone got a clue where I should start looking for the issue before I go out and buy a new player. Thanks in advance👍
What is actualy the cause of "disc error"?
In you case is laser fail, but sometimes help the lence cleaning, but not always because there are two more lences under the upper visible focus lence what we are cleaning + prism lence at the bottom where photo laser beam skew 90° up.
So there are many surfaces which can colect the dirt and we can clean only the upper focus lence and only front side.
Does this laser beam is aging and destroying the plastic structure of lences which become untransparent like the polimer headlamps lences on cars durig the time and the disc is unreadable?
Does the laser become weak during the time or it can only be in state working and not working and nothing between this states like transistors or diode?
Does anybody knows more about?
The lasers themselves rarely seem to be the cause of disks not reading, it seems to be more commonly caused by dirty/hazy lenses, 'sticky' guide rods(such as from dried out lubrication), and various types of misalignment. There are typically multiple pots to adjust different controls, but tiny changes can throw things way off, and can be very difficult to set properly (at least without an oscilloscope and knowing what it should show)
You can clean the entire unit (Black box) into the Walter, and adding liquid cleaner (soap).
I have a meter that reads the output of lasers both diode and HeNe types.
what might one of those be called?
Outstanding video actually. Easily understood, clear vocabulary and terms, although beyond my current knowledge level in terms and definitions, thats my problem to learn. haha... anyhow, thanks very much!!!!
Where can I find KSS 213D lesser lence?
Try Google.
I found one on Amazon:
www.amazon.co.uk/KSS-213-Laser-KSS-213D-Optical-Pickup/dp/B00NYUMFCY
Oooo! you must be the master of all lasers!
You sure know what you are doing, thanks, I am just starting out and got a d in electronics, this helps a lot thanks again ;-)
I have project using this opu (KSS-213C) Thank you for making this video!
but the light is only visible with a camera?
Yes, it's near-infrared - we can't see beyond certain wavelengths(the 'visible spectrum'). Likewise most remote controls use infrared light that we can't see.
Some things like cd lasers aren't visible but can definitely do damage to your eyes!
The red light is presumably just to indicate that the laser is operating.
I think its the wrong type of diode i had a 4 pin and only got nothing out of it too
Great buddy ; good luck !
Your Video suggests that even if we could get new Laser Diodes for our C.D. Players we would need to set up the Optics before we could play anything again.This is a bit disappointing as I had hoped for a nice simple high tech equivalent of changing a Gramophone Needle.
Those lasers can hurt somebody's eye even when reflected
But... if looking at a laser is dangerous for your eyes, isn't filming it dangerous for your camera?
It depends on the strength and exposure time - you can buy a new camera, eyes aren't as easy to replace...
@@e5frog Hey! I know you... You're a commodore fan/hardware junkie aren't you?
@@peterlamont647 I have been known to fondle a Commodore machine or two. ;)
You really helped me. Thank you!
Glad to help!
I was fooling around with my original xbox and came across the laser disc reader a warning label said if was radioactive. If it's not plugged in is it still radioactive?
No clue. Other than Americium in smoke detectors and X-rays emitted from high voltage rectifier tubes in antique televisions, I don't know of any other radiation from household electronics.
It sounds unlikely that a CD player would be radioactive(as in emitting ionizing radiation), however, it might have a warning about laser radiation, and possibly the warning symbol for laser radiation(a filled circle with alternating shorter and longer lines radiating from it, with one line extending to the edge of the symbol). Of course, the laser would only be on if the device was operating at the time.
Eric Wasatonic There are quite a few radioactive things people may have around, actually, but if we limit it to electronic things, an example may be glow or arc discharge based devices(neon lamps, fluorescent starters, HID lamps etc), which may have thorium 232, promethium 147 or Krypton 85 added to help them reliably ignite. I also seem to remember that some vacuum tubes use thoriated tungsten cathodes/filaments, though, If I recall correctly, it was more common for high power tubes used for transmitters than the ones used in general electronics.
Some older instruments and clocks have radioluminescent paint which generally contains radium 226/228, and it is possible to come across it in some electric devices. I would say that any old device or instrument which appears to have or have had glow in the dark paint on it should be checked with a suitable detector before one takes out the screwdriver or gives it to the family's little engineer, just to be safe.
Ömer Hayyam Saydam Well said, old bean.
eric, video muito bom apesar de nao falar ingles entendi tudo.
Tiny bit of visible light could be the same as 1 Watt+ of laser light at fex 780nm, you are very stupid to look directly at these no matter how dim the light is!
Good RND sir
There is a easy way to test this in the player itself. It’s called a oscilloscope that would be a lot easier. What a crap way to test a cd pickup. Also to test a laser you need a LPM meter to test its output and wavelength. This is not how to test a laser diode. It’s the long way when you can do it quicker.
Well said... It would be like testing a floppy drive by pulling of the read/write head and putting it next to a toroid core with some magnet wire wrapped around it...Ruining the drive alignment in the process. The easy way would be to test before the pre-amplifier and after.
Peter Lamont
Well said to you too. Glad you know what your doing. So many bad videos on RUclips showing you diy repair that show you to make things worse. You need special tools to test signals,etc in these devices.
Nice videos! I'm a subscriber...
InTeReStInG. Thank you
Very usefull,Thank You
Well Done & Thanks 4 Not trying To Be A ..... " DJ " !
informative
> 70mA
Oh god!
why is there no in depth information on how to diagnose and repair these things...I fucking hate buying new. and this is the most common fault on anything that reads discs. fuck the system
Because they're very difficult to adjust without the proper equipment and training, also has the potential to damage your eyes. I expect there are technical documents that go through all this, but it seems likely they aren't suitable for most people to understand without prior study.
I don't think the laser itself is the most common problem though, the most common issues seem to be related to dirty lenses and tracking problems.
you are master
hZ
Horrible video ! you are teaching "how to test laser ..... '' when you don't have enough knowledge about it yourself ! Some people who are curious and uneducated (enough) might follow and fall into the same mistakes and even get permanently damaged !
The video has been reported ! if you have some decency, remove the video yourself,
you should start it with the health hazards and warning ..... and for your own sake, i encourage you to learn about laser safety.