Hello, to all the community !
having a bit more time those days, I'm putting back on the table a project from the past....
I had, some times ago, the opportunity to buy a broken cd67se (burnt RCA connector, no display) and wanted to try to fix it (I'm not an electronic expert but hey .. let's try to learn something ; )
After some straightforward investigations, and a replaced RCA connector, I've changed two 7805 (Q811 Q871) with LM340T5. At that moment the display decided to switch on... great !
I've decided then to test rail tension and noticed and issue with the 55V one, as well as the output from 79M18 (Q851). After some diode testing, the zener D852 was dead; a replacement put all 79M18 back in business.
Currently, the player still does not work, the motor does not spin on CD insertion and the tray is very slow to open. All tensions of QF01 being ok, I strongly suspect the 55V rail being the issue (it's currently at 5v exactly what the LM340T5 is supposed to output, so I'm not fully sure of how to gain 55V from 5V ... negative feedback ? )
Investigating now around chips, I've noticed that output tension from TDA7073A Q108 is off (one being 1V the other 4V), of course none of the 7073 are properly powered with 55v, but could I have a ground sink on this TDA explaining that I'm not at 55V ?
I've also checked C155 which seem to be 47µF as well as R125 and 126 that are not 1K but only 800 ohms (I don't think it could explain the tension drop... )
From there, well I think my next step will be to desolder the 'faulty' 7073 to swap it with a presumably working one unless some charitable soul from the forum have some enlightenment or experience to share on this CD player 🙂
Thanks in advance !
having a bit more time those days, I'm putting back on the table a project from the past....
I had, some times ago, the opportunity to buy a broken cd67se (burnt RCA connector, no display) and wanted to try to fix it (I'm not an electronic expert but hey .. let's try to learn something ; )
After some straightforward investigations, and a replaced RCA connector, I've changed two 7805 (Q811 Q871) with LM340T5. At that moment the display decided to switch on... great !
I've decided then to test rail tension and noticed and issue with the 55V one, as well as the output from 79M18 (Q851). After some diode testing, the zener D852 was dead; a replacement put all 79M18 back in business.
Currently, the player still does not work, the motor does not spin on CD insertion and the tray is very slow to open. All tensions of QF01 being ok, I strongly suspect the 55V rail being the issue (it's currently at 5v exactly what the LM340T5 is supposed to output, so I'm not fully sure of how to gain 55V from 5V ... negative feedback ? )
Investigating now around chips, I've noticed that output tension from TDA7073A Q108 is off (one being 1V the other 4V), of course none of the 7073 are properly powered with 55v, but could I have a ground sink on this TDA explaining that I'm not at 55V ?
I've also checked C155 which seem to be 47µF as well as R125 and 126 that are not 1K but only 800 ohms (I don't think it could explain the tension drop... )
From there, well I think my next step will be to desolder the 'faulty' 7073 to swap it with a presumably working one unless some charitable soul from the forum have some enlightenment or experience to share on this CD player 🙂
Thanks in advance !
Nothing runs on 55 volts in a CD player 😉 If you are looking at the output of Q871 then it looks to me to be +5S (its an S, not a 5) which would just be a designation of where it goes to separate it from the other +5 rail.
The tolerance on those regs mean that anything in the 4.8 to 5.2 volt range is fine.
The tolerance on those regs mean that anything in the 4.8 to 5.2 volt range is fine.
There are lots of fusible resistors in Philips/Marantz stuff that can go high in value for no reason. They are usually the ones with warning triangles on the diagrams.
Begin by checking all rails are correct at the PSU and then move on to their destinations. The tray slow to open is something you might be able to work with. Check the supply on the tray motor drive amp under load and make sure it holds up. If not then trace it back.
Which makes perfectly sense ! Damn I feel stupid for that, I thought several times that 55V is kind of high for components I saw... This is not a tube amp ! 😀
Yes I understood the warning icon being the weak parts to check first.
Regarding the tray issue, this is the approch that I had which led me to the 7073 with out of spec output tension (and proper input), so yes I guess I'll give a try to the 7073 swap before ordering a chinese copy ..
In the meantime, I'll try also the service mode to check the optical block.
Thanks Mooly for the guideline ! I'll keep you posted ; )
The 7073 is a floating bridge type circuit. The motor is connected between the two outputs and provided the voltage is the same on each pin the motor does not turn. When the motor turns one pin will fall to ground potential (zero volts) and the will go to close to 5 volts putting the full supply across the motor. To drive the motor the other way sees the output pin voltages reverse.
So if you measure between pins 9 and 12 you should see zero volts for no tray motor operation and then either plus 5 or minus 5 volts depending whether the tray is going in or out.
If you see 5 volts across the motor then the chip is fine. If you don't then measure the supply on the chip itself.
I'm not at home for the week end but as I remember, one pine was at 1v and the other 4V (so we are good for the output).
Considering that I test the board out of the player and not connected to any daughter board, would it be possible that this tension is the expected behavior to keep the tray closed while powered ?
If so, I definitely need to disassemble the optical unit, check the tension of the belt (may be the issue) and clean the lense (it was unable to read a disc and I thought it was due also to the 55V rail ... )
If not, it seems I'm good to undust the 'scope to check signals
The voltages really need checking under load in the fully built up player. Looking a the data sheet and those voltages sound OK (providing the current delivery holds up).
TDA7073
The data sheet suggest the total output voltage is Vp (the supply) less approx 2.1 volts. So that fits with your measurement of seeing 3 volts between the pins.
TDA7073
The data sheet suggest the total output voltage is Vp (the supply) less approx 2.1 volts. So that fits with your measurement of seeing 3 volts between the pins.
Hi ! Update of the day !
After some laser tray disassembly, it appears that the grease used was dead dry explaining why the mechanim was so slow, a dab of oil helped, tension are good. I'll try to find a new belt for that and it will be good for this side.
Now, after some service mode testing, I'm facing the dreaded no disc detected isssue (ERR 02 focus problem). As I'm also facing a clac clac while in mode 3 coming from the sledge (I think it's the proper term). Looking more strictly the teethed plastic line is broken.
So to put it differently, I'll buy a CDM 12.1 replacement unit, clean and grease a bit the tray and hopefully I'll be able to listen something : )
I'll keep you posted ! Thanks again 😉
After some laser tray disassembly, it appears that the grease used was dead dry explaining why the mechanim was so slow, a dab of oil helped, tension are good. I'll try to find a new belt for that and it will be good for this side.
Now, after some service mode testing, I'm facing the dreaded no disc detected isssue (ERR 02 focus problem). As I'm also facing a clac clac while in mode 3 coming from the sledge (I think it's the proper term). Looking more strictly the teethed plastic line is broken.
So to put it differently, I'll buy a CDM 12.1 replacement unit, clean and grease a bit the tray and hopefully I'll be able to listen something : )
I'll keep you posted ! Thanks again 😉
👍 good work on the tray.
If teeth are damaged on the sled then the appropriate parts will need replacement. The CDM12.1 is a 'plug and play' pickup so if it is faulty then hopefully it should be a runner with a replacement. Dried out grease (on the sled) was the number one failure of the CDM12.4 pickup used in some high end players, well the grease was the failure rather than the pickup.
A special plastics/metal compatible grease should really be used on the mechanisms.
If teeth are damaged on the sled then the appropriate parts will need replacement. The CDM12.1 is a 'plug and play' pickup so if it is faulty then hopefully it should be a runner with a replacement. Dried out grease (on the sled) was the number one failure of the CDM12.4 pickup used in some high end players, well the grease was the failure rather than the pickup.
A special plastics/metal compatible grease should really be used on the mechanisms.
Number one failure cause on CD players is any belt it may have. The rubber get's hard, slip and later breaks. The belts are usually a safety featur, if something blocks the tray moving in or out.
Next is worn out lasers. If aviable, a new "no adjust needed" pre adjusted replacement is the way to go. I many cases it is not significantly more expensive to replace the whole CD drive instead of only the laser unit. Drives may have some very small differences to the one used in the CD, like lengt of drive shaft and the spindle driving the CD. Fractions of milimeter decide about working or failure. Sometimes such critical parts can be changed from original to spare part, as they usually don't wear.
As it is hardly impossible and if, ridiculous expensive to get a real set of test CD's, any "adjustment" of the laser should be avoided if possible. I fear more CD player have died from failed adjustment than natural causes.
Smoking is not only bad for your health, but also for your CD player!
For grease or oil if needed, only use silicon based, Nylon and plastic priendly products. The amounts a CD player needs are very, very small, maybe a few milligram.
Next is worn out lasers. If aviable, a new "no adjust needed" pre adjusted replacement is the way to go. I many cases it is not significantly more expensive to replace the whole CD drive instead of only the laser unit. Drives may have some very small differences to the one used in the CD, like lengt of drive shaft and the spindle driving the CD. Fractions of milimeter decide about working or failure. Sometimes such critical parts can be changed from original to spare part, as they usually don't wear.
As it is hardly impossible and if, ridiculous expensive to get a real set of test CD's, any "adjustment" of the laser should be avoided if possible. I fear more CD player have died from failed adjustment than natural causes.
Smoking is not only bad for your health, but also for your CD player!
For grease or oil if needed, only use silicon based, Nylon and plastic priendly products. The amounts a CD player needs are very, very small, maybe a few milligram.
Hi guys !
Mechanism orderd, and silicon grease sitting on my desk ! Ready for tomorrow reassembly 😉
More to come ! thx to both of you
Mechanism orderd, and silicon grease sitting on my desk ! Ready for tomorrow reassembly 😉
More to come ! thx to both of you
then 
The story inside the story? 🙂
Well, back in 2008 I was interrested in making some decent sound system, I've calculated some back loaded horn based on a pair of fostex 206e.
Once done, the idea of building an amplifier came... At that time I was reading since some times articles from Papa Pass... (the Aleph 5 would have been a great build 🙂 ) BUT finally I began a General Electric KT88 push pull build.
I wanted to have also a half good cd player, and at that time the CD 63 / 67 series, due to several tweaks already documented were a no brainer.
I then began to look on ebay and found mine. Sold for pieces, it was clearly stated as not working. The case is not in a marvelous shape and would probably need some paint. Once opened I noticed the melted RCA; I've just checked the circuit board at that time (also in a poor shape with multiple scratches, missing screws .. )
Relocating several times, the cd player stayed in its box quite a long time and moving again recently, I found him waiting ...
Begining my investigations, as stated on my first post, I noticed that both 5v power rails were dead as well as the negative one behaving strangely.
It occurs that both 7805 circuit were dead as well as a regulating zener diode.
I do not have the full life picture of this cd player but from what I assume, it must have seen difficult times. I suspect an electric shock coming from the RCA plug, burning some elements...
And this is the current state (hopefully not the end) of my CD67 life. Maybe I should give it a name ? 😀
Fun fact, this is a cd player bough in UK with a french electric plug oO
If you bring it back to life then you have definitely earned the right to name it! But you paint quite the picture of electric shock treatment in the UK gone wrong...
Well Ladies and gentlemen...
I can officially announce the transplant seems to be a success 😎
The dead is back to life and recoverd its voice.
It still needs some stich here and there (silicon pipes orderd to stop properly the tray where some are missing) (new belt ordered also while its gutsare opened) (proper cable management) (maybe a black paint ..) BUT I can spend some time listening to it.
Well sounds like I have a name to find now ...
Thanks to all 😉
I can officially announce the transplant seems to be a success 😎
The dead is back to life and recoverd its voice.
It still needs some stich here and there (silicon pipes orderd to stop properly the tray where some are missing) (new belt ordered also while its gutsare opened) (proper cable management) (maybe a black paint ..) BUT I can spend some time listening to it.
Well sounds like I have a name to find now ...
Thanks to all 😉