I tried measuring the sense coil with the cable at the main digital board unplugged and it's still 44k, so although it's incorrect it's not completely open circuit. Putting a 3.9k resistor in parallel with the coil will be a quick test to try and alleviate the tray problem. Locking the sled is easy enough to prevent any unwanted movement but if the coil isn't providing the correct signal anyway it may not cause a problem.
I tried powering the player with the tray open and the laser pushed fully back. It moves the laser fully forward and attempts to close. I will try these suggested mods to the coil circuit and TR3 as I've got nothing to lose. I'll post my results later once I've tried them.
I tried powering the player with the tray open and the laser pushed fully back. It moves the laser fully forward and attempts to close. I will try these suggested mods to the coil circuit and TR3 as I've got nothing to lose. I'll post my results later once I've tried them.
The base of TR3 is now grounded and the tray/clamper again operates flawlessly. This time however, the disc loads and plays fine.
I've been sat cycling the tray in and out repeatedly in disbelief but it appears this is the cure.
For me this has ended months (if not years, on and off) of chasing this problem. I certainly owe you a beer(or six!) for your input on this one. Hopefully there will more than a few other happy owners reading this too.
I've been sat cycling the tray in and out repeatedly in disbelief but it appears this is the cure.
For me this has ended months (if not years, on and off) of chasing this problem. I certainly owe you a beer(or six!) for your input on this one. Hopefully there will more than a few other happy owners reading this too.
I've given it a thorough test and it's definitely cured. I'll be swapping it over for my Akai CD-55 which has been stand in for far too long. I'll enjoy a few beers and my music this evening.
Thank you very much once again! Also to all to all those that contributed to this discussion and journey... to a simple wire link! 🍺 😀
Thank you very much once again! Also to all to all those that contributed to this discussion and journey... to a simple wire link! 🍺 😀
The Akai is back where it should be after languishing in the cupboard for far too long. Coupled for the first time via it's optical output to my Pioneer SC-LX86, it sounds very nice and after several hours use is still working perfectly. The tray loads and unloads without any problem every time.
I put a micro from a faulty one into a serviceable device and it worked, but when replaced back, the malfunction persisted.The error is given by the micro itself when it is installed in a faulty motherboard.After a while, a malfunction appeared in this device.From what and why this malfunction appears, so far no one can give a convincing answer.The jumper helped, but after a while the device stopped reading the total time on the disk.One problem has gone-another has appeared.The laser stopped glowing.
Your test of putting the micro from a faulty unit into a good one proves this problem isn't the micro itself.
The jumper 'fix' does certainly alleviate the problem on mine. I suspect yours has now suffered laser diode failure and this isn't connected with the disc tray/sense coil/fault detection problem.
This is more serious because these lasers are very expensive and rare now.
The jumper 'fix' does certainly alleviate the problem on mine. I suspect yours has now suffered laser diode failure and this isn't connected with the disc tray/sense coil/fault detection problem.
This is more serious because these lasers are very expensive and rare now.
Quite possibly.It is unclear at what stage the laser failed.The device worked after installing the jumper, and after a while stopped reading the disk.The first thought was that the laser had finally died, but as it turned out, the laser had completely stopped glowing.We'll figure it out.Thanks!
It could be the two problems are unrelated but since this modification has never been tried before it may well be the cause of the second problem and mine will soon suffer the same fate.
I have to admit after the initial euphoria of it working again, I haven't given it a lot of use. With most of my music collection now converted and stored in digital format, my CDs have become a bit obsolete.
If the laser does die, I think I will call it a day on this one having seen the crazy prices of used ones.
I have to admit after the initial euphoria of it working again, I haven't given it a lot of use. With most of my music collection now converted and stored in digital format, my CDs have become a bit obsolete.
If the laser does die, I think I will call it a day on this one having seen the crazy prices of used ones.
Greetings! I replaced the laser head and adjusted the parameters. The device is now fully operational. I've been waiting for this moment for a long time. Now I'm enjoying the sound! We know how much it works, but the master assured me that I have enough for my lifetime. I will hope that it will be so, that it will be so.
It's been almost a year since the wire mod was installed in my Akai CD73 and all has been fine until this week.
The tray mech still cycles in and out without any issue but now it refuses to play the disc. It reads the disc contents when first loaded but when a track is selected or play is pressed, there is a strange and repetitive chirping sound but the disc will not play.
The only strange thing I've noticed is when selecting a higher track number on the disc, it rotates much slower than usual and the speed varies up and down while it tries to read. I've not had time to investigate this yet but guess the laser is finally on it's way out.
The tray mech still cycles in and out without any issue but now it refuses to play the disc. It reads the disc contents when first loaded but when a track is selected or play is pressed, there is a strange and repetitive chirping sound but the disc will not play.
The only strange thing I've noticed is when selecting a higher track number on the disc, it rotates much slower than usual and the speed varies up and down while it tries to read. I've not had time to investigate this yet but guess the laser is finally on it's way out.
I do remember the thread, pleased to hear its been working well...
I'm going to say you need to scope the RF and see where its at amplitude and quality wise. Although it may be the laser it doesn't automatically follow and I think issues with the platter motor could also do this. Is it a simple DC motor?
I'm going to say you need to scope the RF and see where its at amplitude and quality wise. Although it may be the laser it doesn't automatically follow and I think issues with the platter motor could also do this. Is it a simple DC motor?
I will get my scope out and check the RF to be sure. I did this before while trying to diagnose the tray issue and it was fine.
The spindle motor is a simple DC one if I remember correctly so may be causing a problem. I also noticed if I press eject while it's trying to read the disc is thrown out while still spinning so something isn't right with this.
The disc contents are read when it first loads, so maybe I am being too hasty condemning the laser so soon.
The spindle motor is a simple DC one if I remember correctly so may be causing a problem. I also noticed if I press eject while it's trying to read the disc is thrown out while still spinning so something isn't right with this.
The disc contents are read when it first loads, so maybe I am being too hasty condemning the laser so soon.
I've zapped the spindle motor in both directions and applied some Servisol but no improvement.
The RF isn't clean as before and goes up and down in amplitude and frequency with the changes in spindle speed. Eventually it does settle down if left and starts to play at which point the scope trace is stable.
If I try to skip a track, the problem returns and the process repeats. It doesn't always resolve itself though and the play icon just sits flashing after a while as it seems to time out.
The RF isn't clean as before and goes up and down in amplitude and frequency with the changes in spindle speed. Eventually it does settle down if left and starts to play at which point the scope trace is stable.
If I try to skip a track, the problem returns and the process repeats. It doesn't always resolve itself though and the play icon just sits flashing after a while as it seems to time out.