Author Topic: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371  (Read 6853 times)

0 Members and 1 Guest are viewing this topic.

Online Gyro

  • Super Contributor
  • ***
  • Posts: 6881
  • Country: gb
Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #125 on: May 13, 2021, 06:04:47 pm »
It looks a lot less cluttered like that!  :P
Chris

"Victor Meldrew, the Crimson Avenger!"
 

Offline Vince

  • Frequent Contributor
  • **
  • Posts: 809
  • Country: fr
Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #126 on: May 13, 2021, 06:30:20 pm »
Yeah, I much prefer it this way, much better accessibility/serviceability !!  >:D

Thanks for the info belt-wise. Boy so there are dedicated "calculators", so my question was not that dumb then... it's a real concrete problem...

 

Offline Vince

  • Frequent Contributor
  • **
  • Posts: 809
  • Country: fr
Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #127 on: May 13, 2021, 09:36:31 pm »
Hmmm.... 23H15 here, giving up on the thing for today.


There are two IR sensors on the tray, well table as they call it in the manual. I like to call it the tray/drawer.. because a drawer coming out of the slot in the front panel makes much more sense than a freaking dining TABLE coming out of the same orifice !  :-// Me thinks

Thanks to the schematics, it was all easy to test, at least from an electrical point of view... handling these  carousel changers while trying to service/troubleshoot them, is a major PITA.

Anyway, I managed to test both of them, and to rule out any interconnect/wiring issue, I probed the sensor signals right on the main board PCB, their final destination.

1) One is an integrated emitter/receiver, with some shaping circuitry inside, so it output a clean digital signal out of the box. It detects the position of the carousel as it turns. I get a clean logical signal, and it comes and goes as expected when I insert an object between the receiver and emitter. So that one works just fine.

2) Other one detects the presence of a disc in the current slot. This one is less sophisticated.  A discrete LED and photo-transistor held side by side in a little plastic holder. Pull-up in the transistor collector as you do. So I was expecting a varying analog voltage, and I do get that. I get 5V with no CD present, as expected, then as I bring a CD closer and closer to the sensor, voltage decreases, great, and when I lay the CD on the sensor, I get almost zéro Volt. 0.15V or so. Good enough for the CPU to consider that a low level logic signal, so am pleased.

So.... I am NOT happy that these two sensors work, because they were the most plausible suspects, so now I must dig much deeper to get to the real cause of the problem, so more hours and headaches ahead !!! :-(

But well, as I say, the harder it is, the more you learn....  so let's keep digging.

I checked also the micro-switch that detects the position of the tray. It works fine. Also an encoder that detects the psition of the loading gear.. appear to be doing sensible stuff, I called it good. Opening and closing the tray works fine now anyway, but I thought I would check anyway just for completeness and peace of mind...

So, why the hell does the carousel keep turning all the time ?!   My next though would have been.. yet again a cooked motor driver IC, like I have in that other player. BUT.... I doubt it is that, because... it does not always turn in the same direction. Instead, it does a very predictable dance : it rotates 2 slots worth CC, then changes direction and rotates yet another 2 slots worth in the other direction, then again 2 slots in the oter direction, etc etc... does it this cycle 4 times it seems, then it stops and the unit displays "ERROR" on the VFD display, and even blinks it to make sure you pay attention.

So, since this no erratic dance, it means it's the CPU commanding the carousel, in a determined, voluntary way. So for now, I would say that sensors and motor driver are fine.... and I am left with zero clue as to what to check for next !  :-// 

I would love to have an error code number to be displayed, but it just says "error" that's all. Plus, the service manual does not seem to list error codes anyway. Also, manual is written in Chinglish language(really, Sony ? You even saved money on manuals ?!  :palm: ) which does not help me understand what the service modes actually have to offer me in terms of diagnostics aid...

23h35, going to bed. Might wake up tomorrow with a bright idea, you never know...


 

Offline Vince

  • Frequent Contributor
  • **
  • Posts: 809
  • Country: fr
Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #128 on: May 13, 2021, 09:39:34 pm »
Oh, and I forgot.... the rotary encoder/knob on the front panel that's used to select the track you want to play... it's acting up, great !!!  :palm:
According to the schematics it's a mechanical one, not optical. So there is a remote hope that I can try some contact cleaner, but if that does not do it, I won't be selling that player with a dodgy encoder... don't want negative feedback !  :-DD

Won't replace it either of course, would eat any profit I might hope to make when selling the thing.


 

Online Gyro

  • Super Contributor
  • ***
  • Posts: 6881
  • Country: gb
Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #129 on: May 14, 2021, 10:03:49 am »
There are two IR sensors on the tray, well table as they call it in the manual. I like to call it the tray/drawer.. because a drawer coming out of the slot in the front panel makes much more sense than a freaking dining TABLE coming out of the same orifice !  :-// Me thinks

I did wonder why the tendency towards multi disc players - you wouldn't find any self-respecting vinyl addict using an autochanger turnable (remember those?)  :)

You seem to have covered everything that I would have thought of ie, check the sensors - I suppose you checked the signals right back to the micro pins (just in case it has a bunch of dry joints). Likewise the encoder. I don't know if it's possible for the gears / sensors to get out of sync? It depends whether somebody else has already tried to fix it. Just a thought.

It's irritating when it's 'deliberately' doing the wrong thing - from your description of the backwards / forwards it sounds as if it is definitely searching for a sensor input that it is not getting (sensor out of sync, dining table position out by 180 degrees?)

Quote
I would love to have an error code number to be displayed, but it just says "error" that's all. Plus, the service manual does not seem to list error codes anyway. Also, manual is written in Chinglish language(really, Sony ? You even saved money on manuals ?!  :palm: ) which does not help me understand what the service modes actually have to offer me in terms of diagnostics aid...

Hopefully you mean 'Japlish', unless Sony were so cheap that they subbed out their design and manual writing too!


P.S. From my past career, I am experienced in understanding and writing in Konglish. Of course, without the 'lish element I am totally screwed! This probably explains my difficulty with Californian, which bares only a passing resemblance to English.  :D
« Last Edit: May 14, 2021, 10:20:49 am by Gyro »
Chris

"Victor Meldrew, the Crimson Avenger!"
 

Offline Vince

  • Frequent Contributor
  • **
  • Posts: 809
  • Country: fr
Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #130 on: May 15, 2021, 12:10:26 pm »
Sorry for being late... worked on the thing 'til almost midnight last night, was exhausted, too late and tired to report back.


I did wonder why the tendency towards multi disc players

There seems to be a pattern indeed, judging but the success of my two 5 disc changers. Also, the guy over at 12voltvids repair channel on YT , commented about this very thing. He too noticed an appetite for 5 disc (carousel) changers (not sure about 6 disc cassette changers though), which he can only explain this way : "You get that hot chick at home, turn the machine on at the start of the date and just forget about it. You dont want the music to stop suddenly while in the middle of.... ahem. ". I don't know.
Personally, I do enjoy my old Philips CDC486 6 disc cassette changer. Whenever I work on, the lav it always takes hours on end, I just want some background music. I just hit PLAY when I start working, and power the thing off at 2AM when I am too tired to work on the bench and decide to go to sleep.
I really don't fancy having to stop what I am doing every hour or so, to swap CD's ! I just hit PLAY and forget about it.  Using a single disc player and getting it it to repeat the disc endlessly, is not a satisfactory option I am afraid  ;D

Quote
[..] you wouldn't find any self-respecting vinyl addict using an autochanger turnable (remember those?)  :)

Gyro, big mistake here !  :P  You are assuming that people are trained and passionate audiophiles ?!
Obvisouly nothing could be further from the truth, otherwise CD player manufacturers would never have been able to sell hundreds of millions of their CD players for a couple decades !  ;)

Also, audiophiles tend to seek perfection (something they can't even define in accurate technical terms) for the sake of it. Most people do things to achieve a goal, not for the sake of doing something as such.
The goal of listening to music is to get emotions. Will I have zero emotions if I listen to my favorite songs on a TDA1543 and be flooded with tears wit ha TDA1541 ?! No of course. The later will be more a little more enjoyable, but I would still enjoy my music on the former, as I am doing right now as I am writing this. Because the emotion in the music is not conveyed by its technical perfection... thank god there is more to music than numbers and maths. There is irrationality.
Would you not love you other half if she got a cold and her voice sounded different than when you first met her ? I hope not.. because there is more to her than just he voice. You won't dump her or divorce because her voice sounds a little different.

So, it's functionality first. As long as the changer put out sound, it's good enough for people.

So maybe I could specialize in 5 disc players, knowing they sell better than the single disc ones.
Single disc one I could specialize in the old Philips like my CD824, ie old enough to interest Philips collectors/speculators, therefore command decent/worthwhile prices, but too crap technically to be of any value to me, so I am not tempted to keep them for myself and therefore lose money rather than make any...


Yeah, maybe with these two kinds of players, I could make buck here and there from time to time, can't hurt, I need every penny to build my house.

Quote
You seem to have covered everything that I would have thought of ie, check the sensors - I suppose you checked the signals right back to the micro pins (just in case it has a bunch of dry joints).

Almost. Accessibility is a pain on this unit, so I did the best I could in my first / quick attempt : I probed on the main board, on the top side of the connector.
But since the signals were OK there, I dug farther and pulled the (single sided) main board so I could check the underside (where the CPU is soldered). NO dry joints, traces in perfect condition. The sensor for the turn table is digital and goes straight to the CPU pin. However the signal for CD detection is analog and does not go straight to the CPU. In between there is a PNP transistor and a couple resistors, that invert the polarity of the signal. I checked the output of the inverter, works just fine.
So, the CPU does get good table and disc sensors signals.  I don't think there is any synchro to be done for the carousel. Manual does not talk about it, and underneath the carousel you can see lots of slots/slits for the optical sensor, carefully laid out to encode the position of the carousel. The whole point I think is precisely to let the CPU figure out by itself the position of the carousel.


Quote
It's irritating when it's 'deliberately' doing the wrong thing - from your description of the backwards / forwards it sounds as if it is definitely searching for a sensor input that it is not getting (sensor out of sync, dining table position out by 180 degrees?)

It indeed looks like such "complex" and repeatable behaviour can only emanate from the CPU, something clever... however I am slowly considering that it may not be the case....somehow  ?I mean, I  am so clueless and baffled, that I am now considering any possibility, as long as it gets the thing fixed ! LOL

Here are the things that would make it strange if it were the CPU at fault : the problem is present at ALL times... even if :

1) I put the unit in table maintenance mode.

2) I open the tray.

3) If disconnect the front panel, and the CDM / BD board. leaving nothing but the main board connected to the turntable motors and sensors. In that case, I would expect the CPU at power up to be somewhat disturbed by the lack of front panel and CDM / player, at least sufficiently disturbed to decide there must be something better to do right now, than play again with that bloody turntable...

A corrupted CPU firmware ? I guess that's very low on the list...

Things that may point to a H/W issue :

1) When the carousel moves from one slot to the next.. and back again, between two slots it always, consistently kinda stops, but not really : it slows down to a crawl, makes a sorry "grinding" noise while moving extremely slowly, like a millimeter a second... then all of a sudden starts moving fast, smooth and quiet again... and the cycle repeats. So, this means the CPU is would be programmed to be able to generate analog voltages to command the motor driver IC, so that it can vary the speed. Sound unlikely....

2) I sometimes, sometimes, notice that the other motor, the  "loading" motor as they call it, the one that opens the tray... well sometimes it TOO does some completely weird things. "analog" kind of  things....  Both motors are driven by the same chip.... chip that drives nothing but these two motors...

So since I am desperate and the sensor/CPU basic checks lead to nowhere, I am now starting to get at the bottom of things :

1) I had to replace the loading motor belt, and carousel belt, since the original belts were too tired / loose to work at all.
I dismantled 4 CD players, hoping to find belts in them that would do the job. All I could find where belts that were either a tad too long hence useless, or way too short, like half the size (not kidding). Yet, even at half the size, they would stretch and not break. So, given no alternative for now, I used these super tight belts.
So, to rule out a problem with these belts, or a tired motor say, I tested the table outside the CD player. I powered the carousel motor and loading gear motor directly with my lab power supply. Result ?  My super tight belts work just fine. Carousel turns effortlessly, smoothy and quiet. The loading motor works fine too. Healthy, smooth.... works just fine.

So now I can rule out any belt motor or gear problem. The mechanical stuff does work fine !
So if it does funny things, it can only be the electronic stuff commanding it.

2) Now next on the list : I will try to power the motor driver IC board (it's not part of the main board), independently, to see if it does funny business or not.
I mean, it uses the same kind of driver IC that failed in that other Sony player I am currently fixing as well (waiting for china to deliver that chip...) So maybe the chips from this manufacturer are just crap...
The cycling nature of the carousel movements might be explained by a capacitive effect of some sort, potentially ? Potnetially.

3) if the driver board does not misbehave on its own, then next thing to do is plug the driver board back to the mainboard, and scope the input signals of the driver IC, to see if they correlate with the misbehaviour. IF they do, the CPU is sending them. If they don't... the driver board/chip is doing it on its own.

So, planning on do that this afternoon. Stay tuned  ;D


Quote
Hopefully you mean 'Japlish', unless Sony were so cheap that they subbed out their design and manual writing too!
P.S. From my past career, I am experienced in understanding and writing in Konglish. Of course, without the 'lish element I am totally screwed! This probably explains my difficulty with Californian, which bares only a passing resemblance to English.  :D

Ah well, you know more than I do so... maybe Japlish it is, maybe !
Tell me your thoughts : here are below the 3 pages of the manual that pertain to the maintenance mode...

 

Online Gyro

  • Super Contributor
  • ***
  • Posts: 6881
  • Country: gb
Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #131 on: May 15, 2021, 04:36:27 pm »
Yes, that's Japlish - it was designed in Japan. Very grammatically correct short phrases (some errors this case), and no accidental substitution of inappropriate words, but shows the typical lack of underlying detail that helps explain what's actually going on.

Ok, I take your point on the multi-disc players - I remain to be convinced that the benefits outweigh the added complexity though. ;)
« Last Edit: May 15, 2021, 04:44:21 pm by Gyro »
Chris

"Victor Meldrew, the Crimson Avenger!"
 

Offline Vince

  • Frequent Contributor
  • **
  • Posts: 809
  • Country: fr
Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #132 on: May 15, 2021, 04:58:14 pm »
Ok, I take your point on the multi-disc players - I remain to be convinced that the benefits outweigh the added complexity though. ;)

Yes, complex they are, and worst of all a royal pain to work on, and way too many gears of fancy shapes. just begging for trouble.

Much prefer the 6 disc cassette changers. Simpler and easier to work on.

OK, I just soldered and labeled 13 wires... to the connector on the motherboard that goes to the table. This way I can probe any power rail or I/O signal while the unit is assembled, in a working state....

That showed that the back and forth movement of the table is indeed commanded by the CPU. Driver board I powered up stand alone, nothing happened, which is good. So either the CPU has lost its mind and therefore the player is good for the scrap pile... or I need to spend more time experimenting, trying to understand how this changer works, in greater detail.  :-\

However it looks like the motors sound tired... but since I know for a fact that they aren't, that means the driver chip might have weak outputs...
Its power rail, negative 10Volts, is solid, no problem there, hence I am suspecting the chip  :-\  Again, I could test for this, standalone, to isolate that driver board from the player. Will do that...

But... I have a bigger problem right now : the way too tight/small belt I fitted to the carousel motor.... just snapped.. didn't last long.
So now, I really do need to order proper belts if I want to go any further.... hoping to find super cheap ones on-line, let's see what I can find...

Shakal if you know of a place that sells this stuff in France or Europe (ie not the UK anymore...), please share !  ;D





« Last Edit: May 15, 2021, 05:00:47 pm by Vince »
 

Offline shakalnokturn

  • Super Contributor
  • ***
  • Posts: 1499
  • Country: fr
Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #133 on: May 15, 2021, 08:26:06 pm »
I can get you belts cheapish through ASWO on my next order and forward them through snail mail if needed.
If you give me the approximate dimensions I'll list you the closest available.

As Gyro suggested the most likely may be something mechanically out of sync but I haven't looked at the SM for further clues.
 

Offline shakalnokturn

  • Super Contributor
  • ***
  • Posts: 1499
  • Country: fr
Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #134 on: May 15, 2021, 08:43:05 pm »
Looking at your pictures there are sync holes for the tray ejection and transport lifting, I don't see much for the disc selection though.

How is the turning platter disc numbering encoded on the hidden side? Single slot for each? Unique sequence for each position? With one disc loaded have you checked that the reflective sensor works as intended.
Once again when testing optical sensors beware of ambient light, I've been caught out a couple of times. Sometimes it's worth turning your workbench light away or off while testing.

Other than that maybe check CPU power, reset, clock.
 

Online Gyro

  • Super Contributor
  • ***
  • Posts: 6881
  • Country: gb
Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #135 on: May 15, 2021, 08:50:38 pm »
Once again when testing optical sensors beware of ambient light, I've been caught out a couple of times. Sometimes it's worth turning your workbench light away or off while testing.

Good point, I remember getting caught out by that one on a VCR.
Chris

"Victor Meldrew, the Crimson Avenger!"
 

Offline Vince

  • Frequent Contributor
  • **
  • Posts: 809
  • Country: fr
Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #136 on: May 15, 2021, 09:00:39 pm »
Thanks for your kind offer Shakal !  :D

Hopefully I won't have to bother you on that one.. just check Ebay without any hope, but what do you know... it's not just old Philips players that attract belt sellers... looks like Sony stuff is popular too, my luck !

Found a guy in Germany that sells both belts in a kit, for 11,45 Euros shipped.

https://www.ebay.fr/itm/274719912069?hash=item3ff6953085:g:FMoAAOSwwlVgTiIo

Still 100 times more expensive than what it costs, but since I don't have any relative in the Chinese belt factory, 10 Euros it will have to be. Still kinda reasonable, for 2 belts. If that's all I need to fix the unit then I should be able to make a profit on the thing.

Of course if you can get them for 2 or 5 Euros, I would go with you instead !   ;D
.. but I would have to get the length right, whereas if I get the kit, hopefully I won't have to worry about it...

OK will buy that, and if they don't fit well, will measure and contact you...

Sync wise, manual gives instructions regarding the loading gear, but nothing about the table/carousel.  I will check the loading gear sync then, though I have no reason to believe that the guy who gave that drive to me messed with that... all he did was pop the hood so he could retrieve his CD's that were stuck inside, that's all...

What the heck, manual is "only", 3.3MB, so should be able to attach it here, let's seee....

This drive is exceptional.... not in good way though : just checked the procedure to adjust  the laser drive and check the eye pattern.
Manual says that... uhhhhh....  " the drive is designed so that it does not need to be adjusted " !!!!   :o
So they tell you how to check the eye diagram, but if it's out of spec then tough luck, can't adjust anything !  :--

 

Offline Vince

  • Frequent Contributor
  • **
  • Posts: 809
  • Country: fr
Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #137 on: May 15, 2021, 10:47:08 pm »
oops, our messages collided...

[..] I don't see much for the disc selection though. How is the turning platter disc numbering encoded on the hidden side? Single slot for each? Unique sequence for each position?

Looks like there is a unique sequence for each disc. For each disc there is a series of tabs that make up slits for the sensor. One disc has 2 tabs so one slit, next one 3 tabs so 2 slits etc, up to 5 slits. So it adds up nicely, makes sense...
Disc number one i snot the one with one slit, but who cares, the CPU is free to number them internally as it wishes...

Quote
With one disc loaded have you checked that the reflective sensor works as intended.

Yes I checked carefully for that in a previous message. The sensor for the platter as you call it, gives a TTL digital signal. Works just fine. When I put an object between the receiver and the emitter, it dos switch between ground and +5V as expected.

The disc detection sensor is analog though, and it works fine too. when no CD is present I get 5V as expected, and as I progressively get the CD closer and closer to the sensor, the voltage decreases (photo transistor with a pull-up resistor) down to almost ground (0.15V, good enough) when CD is positioned on the platter, as it's meant to be. Signal then goes to the main board where it is inverted by a PNP transistor, then goes to the CPU pin. That part works too.

Quote
Once again when testing optical sensors beware of ambient light, I've been caught out a couple of times. Sometimes it's worth turning your workbench light away or off while testing.

Good point... tried that, no change at all. Not really surprised since I tested the sensors with full lighting and even this way, they work perfectly fine... but worth keeping in mind for future repairs...



Anyway, played with the thing for a bit. Since the table belt has snapped, I turned the carousel by hand, for long minutes, in one direction, then in the other... opening the tray.. closing it.. pressing " PLAY "... tried to see if I could get it to react in some way... and it did react !

1) Normally, after doing it's carousel dance a few times, 3 or 4 cycles can't remember, it would then stop and display 'ERROR3. Wel, I noticed that as long as keep turning the carousel by hand regularly, it never gives up and never throws ERROR. It just keeps trying. So I guess that means it sees "some" activity from the platter sensor, which causes the drive to insist.


2) With one single disc present, I noticed that it would eventually "build" it'sd map of what slots were empty or not, and after a while turning the carousel, eventually at some point the VFD display would acknowledged the fact that indeed, there is only oe disc present, and it would also get the number right. I put the disc in slot #2, and that's what it displayed. So that's encouraging !  :D

3) I managed, twice, after great effort, lots of patience, lots of turning, pushing buttons.... to make it CLAMP a disc, spin it a read it !!!!   TWICE !
Right now it's playing !   :D

So it CAN do it...


However, the loading gear is SOOOOOO weak , that it barely can clamp the disc or operate the tray !!  ... even though it tested just fine when I powered the motor directly with my lab supply !  So weak that I am sure it tried to clamp the disc several times but I didn't even notice it because it was so slow to gete moving that the player gave up and started trying to rotate the carousel again.

Then tried putting 5 discs in the carousel, fully loaded. IT seems to recognize that all slots are occupied : display says so.


So it's encouraging.

The first thing now is to sort this belt problem once and for all. So I will order those belts.
Then see why the loading gear ss so weak, unable to operate without assistance, even though the motor works super fine. 

Until I receive the belt, there is no point doing further test I think.... so I will get back to you once I have those belts. But since I will buy them from Germany, hopefully I should receive them in just a few days, not a few weeks...

Tomorrow, something different on my plate : must work on all the paper work and drawings for the building permit of my garage/workshop.  It got refused a couple years ago, the complained about a dozen things... need to rework it and submit it again... need the garage to store all my electronic gear somewhere else than the living room !  :P

Stay tuned.....
 

Offline Vince

  • Frequent Contributor
  • **
  • Posts: 809
  • Country: fr
Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #138 on: May 16, 2021, 09:34:54 pm »
OK, did work on thje building permit, pfff... did some work on the dry walls in the toilets though, almost there ! so was not totally unproductive...

Worked on the player a bit more in the end !  Because... as I was gathering all the screws and bits in a box, to store the thing while waiting for the belts... what did I see on the bench ?! A belt that was the perfect size for the table motor ! Way too short for the loading gear motor, but just the right size for the table, hooray !  :D   

So I was back in business, hence I could not help but resume troubleshooting...

Worked on the loading gear motor to try and se why it's so weak. Noticed suspicious joints on the driver board, precisely at that motor connector ! Fixed that promptly. Definitely better now, but still far from good, definitely not acceptable. It's having an extremely hard time getting started. Once the drawer is on the move, it gets easier and moves at a normal speed. So it's better, but still need some work.

Soldered a couple wires to the two output pins of the driver IC (a BA6780 ) so I could watch the output voltage in real time as the motor is working.
No wonder it's so weak/useless :

1) When I ask the player to open the drawer : at startup, it gets 3,7Volts or so, wayyy too low to do useful work !  Once the drawer is finally moving, voltage increases to 6V and it opens up at a normal speed, I would say.

2) When I then ask to close it, again I get 3,7V at startup, very slow start, but then it does not get better, it goes slow al the way til the end, have to push by hand it to help it, then when it's fully retracted and motor is going to stop, it gets 2+ Volts.

I don't know what voltage it's SUPPOSED to get. Tried to figure it out. The data sheet shows that there is a pin that let's you adjust just that. However it does not give details on how it works, how to calculate the thing. The schematic shows that this pin is set by a voltage divider between the supply voltage and another pin no the chip, which outputs an internally regulated voltage.of 4.6V.  Problem is : the supply voltage for that chip can be pretty much anything. In this CD player it's a single rail, negative. Runs purely on negative 10V rail (yet can take TTL level inputs from the CPU...).
so how can it generate a positive voltage reference, from a negative rail and nothing else ?
So that means basically I can't trust this datasheet... so I can't know for sure how much voltage the chip is set to output.
Yes, I hear you...  "Look Vince, what do you bother retro-engineering this thing, all DC voltages are noted on the schematic, just read ! ".

Yeah ? Really ? Schematic says that the outputs are -12.6V and +12.6 V !!! How plausible is that when the chip has a single -10V supply ?!!!  :--
Even funnier : look at the schematic for the main board, precisely the 7805 regulator (hence +5V) for the CPU, what does it say ? Input voltage of NEGATIVE 10V, and output of +7.1V !!!    Now how much should I trust DC voltages in these schematics, please, tell me ???   :-DD

Looks like they put as much effort/care in these schematics as did in the translation job ! :scared:

So... I don't know what freaking voltage this motor is supposed to get ! Best I can say is : "maybe 6V, because that's what I measured when the tray was moving at what looked like a normal speed, plus it's what the schematic says... so maybe it's correct at least for these 2 pins...

So, why does it get only 3.7V at startup, or all the way when retracting the drawer ?
Checked the - 10V power rail, it's solid, does not drop when the motor. So maybe the chip's output are weak, don't put enough current ? Datasheet says 1.5 Amps or so max current, but they don't say it's including both motor drivers, or if it's per motor. When I tested the motor on my bench power supply, had no weak start, but the supply of course can supply 3 amps.

What I am thinking is that it might be combination of two things, perhaps :

The belt I put as I said, is wayyy too short, so might give the motor a hard time since these have so little torque. It can still do it with the bench supply, but maybe requires more current than the driver IC in the player, can supply.

So maybe once I put the appropriate belt on it, motor will require less current, the driver IC will be able ti supply, and voltage will go up, and motor will be happy again ???  I don't know... but I am not wasting time chasing red herrings... I will leaved it at that until I can replace the belt and reassess the situation...


That was for the loading motor.

Then I worked a bit on the sensors. I told you they tested fine, even in ambient light, when I did a static test and checked with a DMM.
So, next step, I scope these signals  while the carousel was turning, to get real world data... see below.

The table sensor gives clean TTL pulses as you would want/expect.
Then the disc sensor, which gives an analog voltage. We can see that it gives a clean, sharp negative pulse (inverted into a positive pulse by the time it gets to the CPU), like clock work, every time a disc passes over the sensor. Looks good to me ?!..........
Yes, yes.... I did try putting the cover back onto the unit so that it's dark inside the thing... that does not change anything at all.

Every once in a while, really rarely, the carousel slows down not in between discs, but very near the axis of the spindle. When it did this, I forced the carousel (takes quite a bit of force, the bugger is very strong) to be aligned perfectly with the spindle, and hey presto it clamped the disc (extreeeeeeemly slowly, though) and it played music !


So for now, I will say that :

1) loading mechanism and its sensors work just fine, just need to fit the proper belt.

2) problem is limited to the table, player just can't detect the position of the table, despite receiving what looks like clean and valid signals from the relevant sensor. It's still a mystery to this day....


Nearly midnight, gotta work tomorrow like the rest of you, so good night !  :=\




 

Offline tautech

  • Super Contributor
  • ***
  • Posts: 21686
  • Country: nz
  • Taupaki Technologies Ltd. NZ Siglent Distributor
    • Taupaki Technologies Ltd.
Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #139 on: May 16, 2021, 10:01:02 pm »
Thinking out loud.........
Would the tray and carousel sliders/bearings/bumpers/guides benefit with some of that special plastic grease you have ordered ?
Avid Rabid Hobbyist
 

Offline Vince

  • Frequent Contributor
  • **
  • Posts: 809
  • Country: fr
Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #140 on: May 16, 2021, 10:07:23 pm »
Have already applied the stuff everywhere in there !  >:D

Somehow the slider and loading gear were completely void of any grease, like the factory back then didn't deem necessary to use any, hmmm.....  :palm:
 

Offline shakalnokturn

  • Super Contributor
  • ***
  • Posts: 1499
  • Country: fr
Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #141 on: May 17, 2021, 12:00:46 am »
For your slow tray wait for the right belt as decided. Too tight and you get a lot of extra friction on the plastic axis in some cases.

On the platter have you checked "S200 rotary encoder, table address detect"? If there are both electromechanical and optical sensors for platter angular position there is a possibility that the mechanical sync is bad or that a switch has a bad contact.

Is the 6 conductor FFC in good condition, breaks aren't always easy to see.

I can get most small "square" belts for 0.5 to 1€ (excluding VAT and postage).
« Last Edit: May 17, 2021, 12:07:22 am by shakalnokturn »
 

Offline Vince

  • Frequent Contributor
  • **
  • Posts: 809
  • Country: fr
Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #142 on: May 17, 2021, 06:07:26 pm »
I can get most small "square" belts for 0.5 to 1€ (excluding VAT and postage).

Oh great, that sounds like a reasonable price !  So that means I wasted 10 Euros on Ebay, my profit margin could have been much better !
Oh well, that will be for next time ! ;D


Quote
On the platter have you checked "S200 rotary encoder, table address detect"?

Yep I checked it yesterday (pics below), because it's name sounds "promising".. Table.... Adress.... sounds good !  ;D
I opened it to check the internals of it, Looks fine to me.  All 3 "fingers" are in good shape, still "springy". They make a reliable contact when I checked all 3 fingers for continuity with the DMM. I put some contact cleaner in the thing anyway, can't hurt.

Quote
If there are both electromechanical and optical sensors for platter angular position there is a possibility that the mechanical sync is bad or that a switch has a bad contact.

... that encoder actually does not encode the angular position of the platter/carousel, at all. It's not even located on the table like the other two optical sensor. Nope, that encoder is linked to one of the loading gears, on the chassis. So it can tell the CPU in what "state" the loading mechanism is, but that's it. It can not tell the CPU the position of the carousel...
But, I checked it anyway, for good measure, and because I have run out of ideas....

Quote
Is the 6 conductor FFC in good condition, breaks aren't always easy to see.

Yes I checked it a few days ago. Looks like new and all 6 conductors check good for continuity. Also, the wave forms I attached in my previous message where scoped on the motherboard, so the entire signal path is taken into account.


Have something new on my plate as of 30 second ago. A neighbour just brought me a dead beefy industrial 3 phase motor speed controller  he bought decades ago. Telemecanique "Altivar".. a boat anchor. Said I could have it for parts if I help him wire another a newer controller he bought as a replacement. Old too, but newer, Altivar n° 5.  I am not into electromechanical stuff but well, it's still made of electronic components hey...
Lots of good stuff to salvage in the thing. Beefy power resistors, beefy diodes and transistors, or thyristors rather I guess... beefy caps, beefy everything really !

Who said nerds are not social people..... having my lab on display by the living room window, actually intrigues and attracts people, they come to me... it turns me into a sociable person, who would have thought...

 

Offline Vince

  • Frequent Contributor
  • **
  • Posts: 809
  • Country: fr
Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #143 on: May 17, 2021, 07:51:35 pm »
Huuuuu...... just checked that CD player on Ebay.... goes for 60 to 100 Euros or so, "as is"...   :o

A serviced unit might be worth more than the  30/40 Euros that I thought, then !

My first 2 players as well... I sold them so quickly, and the buyers didn't even remotely attempt to lower the price... it's suspicious ! Maybe I could have sold them for 50 or 60 Euros ?! Sounds a bit high to me but well, will try next time, see what happens... nothing to lose !

Motivates me to dig deep to try to fix that mysterious table issue...
« Last Edit: May 17, 2021, 08:47:36 pm by Vince »
 

Offline shakalnokturn

  • Super Contributor
  • ***
  • Posts: 1499
  • Country: fr
Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #144 on: May 19, 2021, 07:19:18 pm »
I don't know how you do it... I've been trying to sell a working Kenwood DP-850 with new belts and refreshed solders for 35€ shipped for over a year now! Actually I handed it over to an acquaintance who has a vintage HiFi store today, maybe he'll get rid of it.
 

Offline Vince

  • Frequent Contributor
  • **
  • Posts: 809
  • Country: fr
Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #145 on: May 19, 2021, 07:45:08 pm »
That looks like a nice player, would not mind having it !   ;D
Looks a lot like my old Toshiba.

35 Euros INCLUDING shipping ?! Shipping is 10 Euros or so, not including the packing material ! Even if you got the player for free which I am sure you did  ;D that's only 20 Euros for your time and belts... for ove ra year of waiting ?! Not worth your time indeed !  :scared:

Maybe I just got lucky then. The two buyers happened to be local and their player quit the day before.

I will see how my other players will be doing when I  finally have them fixed... probably won't get as lucky !
Well if they don't sell I will just keep them for parts and move on... I bought them all only to get experience, not to make money... if I can shift some of them to recoup some of my "investment" great, but if not, won't cry. Selling 2 players at 40 Euros already recoups a significant part of the 300 Euros I spent in these 20 or so players...


Just received today a CDM12.1, hoping that would fix my Philips CD 720. Just like last time I ordered a CDM12.1, ad says it's "NEW".. but clearly isn't at all... crusty looking wires and solder joint crusty everything... and they did NOT even short the pickup flat flex !  :scared:   
NOT holding my breath on that one, but well, might work well enough for me to dare putting the drive up for sale...

Philips CD824 is ready for sale. Tray gear and belt replaced, fresh plastic grease everywhere, did help make the drawer mechanism sound a bit less shitty.


 

Offline shakalnokturn

  • Super Contributor
  • ***
  • Posts: 1499
  • Country: fr
Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #146 on: May 19, 2021, 08:38:54 pm »
Just received today a CDM12.1, hoping that would fix my Philips CD 720. Just like last time I ordered a CDM12.1, ad says it's "NEW".. but clearly isn't at all... crusty looking wires and solder joint crusty everything... and they did NOT even short the pickup flat flex !

F'ing eBay has become a right rip-off, I used to ask for at least partial refunds in similar situations, now most sellers accept returns so unless you're willing to pay to return and expect them to be honest when they weren't from the start... You're stuffed!
Now I live with the bought defects and lost money, give negative feedback and move on.
I just avoid eBay when possible, I've had better customer support from AliExpress in the past years.

I'll have a quick look at that Pioneer CD player previously mentioned tonight, I'll let you know if there's a spare lens going soon. I have a Sharp CD to check too.

Need to get some stuff out of the way to buy more dead TE.
Missed a MX54 at 25€ on Leboncoin this afternoon, the seller said a lot of people had asked... Really?
 

Offline Vince

  • Frequent Contributor
  • **
  • Posts: 809
  • Country: fr
Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #147 on: May 19, 2021, 09:24:01 pm »
F'ing eBay has become a right rip-off, I used to ask for at least partial refunds in similar situations, now most sellers accept returns so unless you're willing to pay to return and expect them to be honest when they weren't from the start... You're stuffed!
Now I live with the bought defects and lost money, give negative feedback and move on.

Didn't have much choice but to buy on Ebay, got it for 10 Euros shipped.. anything more than that and I would sell the CD player at a loss (assuming I can manage to sell it, that is...). So it was either I tried this, or not spend any money on it and just consider it a parts unit...
But hell, maybe it works ! LOL   Previous one was used too yet it worked just fine. So maybe I will get lucky with this one too...


Quote
I just avoid eBay when possible, I've had better customer support from AliExpress in the past years.

Yeah there are other web sites / places indeed. Bangood or god knows what else, but  it's a pain having to create multiple accounts and check 10 different sites for each and every time you need the slightest little thing.. OK I am lazy I guess...  :-//

Quote
I'll have a quick look at that Pioneer CD player previously mentioned tonight, I'll let you know if there's a spare lens going soon.]I'll have a quick look at that Pioneer CD player previously mentioned tonight, I'll let you know if there's a spare lens going soon.

Thanks, crossing fingers !  ;D
Worse case, since I have absolutely nothing to lose, I was toying with the idea of, please forgive me... pull a lens from whatever parts unit I have laying around, and see how it breathes some life into the Pioneer !  :-DD


Quote
Need to get some stuff out of the way to buy more dead TE.

Same here !  I am starting to feel the urge to get rid of all these CD players and get more TE !  :scared:

Quote
Missed a MX54 at 25€ on Leboncoin this afternoon, the seller said a lot of people had asked... Really?

Wow !  :o   Good deal indeed !  I didn't even see that ad ! Got removed instantly. I missed two marvelous TE deals too, the past few days. Posted on TEA about it. Still crying.

There is a nice MX 53C in pristine condition in its original box, with its test leads and booklet/manual, for 40 Euros. That is (still available) a nice opportunity too, but sadly the seller says he won't ship... WHY ? Not that it's fragile or heavy or large....
So I gave up on it.... but I already have a dozen MX 53/54/56, so I guess I don't really need yet another one... It's so hard to be reasonable with TE !  :-//


« Last Edit: May 19, 2021, 09:28:39 pm by Vince »
 

Offline shakalnokturn

  • Super Contributor
  • ***
  • Posts: 1499
  • Country: fr
Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #148 on: May 20, 2021, 08:48:55 am »
I missed two marvelous TE deals too, the past few days. Posted on TEA about it. Still crying.

I inquired on that Tek 224 too, didn't have a chance either... At least the seller bothered to respond.


The Pioneer CD player seems to be working. (I'll have to check the audio output some time all the same.)
The original pickup was sensitive to vibration at the best, laser power had to be turned down to detect CD, but the hidden side of the lens was dirty so I assume that it had been turned up at one point.
Anyway I unstuck the lens again to fit it on the pickup from the sacrificial 6 CD player. Much better!

I think your plan to throw the odd lens on the pickup and see how it goes is reasonably insane.
I measured the lens I had although my Pioneer pickups differ slightly from yours. Inner diameter: 6.33mm, outer diameter: 7.33mm, overall hight: 3.41mm, focal distance: 4mm approx.

 

Offline Vince

  • Frequent Contributor
  • **
  • Posts: 809
  • Country: fr
Re: Vintage CD player repair : Philips CD 371 AKA Radiola CD 1371
« Reply #149 on: May 20, 2021, 09:50:30 pm »
I think your plan to throw the odd lens on the pickup and see how it goes is reasonably insane.

I like your style  >:D
Might give it a try, nothing to lose...
Plus the front panel being cracked I can't sell it any way... so it's all just for the fun and curiosity to see what might happen...
[/quote]

Philips CD720 : before replacing the CDM12.1, I tested the unit again, as it's been 2 weeks now since I last touched it. Player had random difficulties detecting or playing a CD. But today it worked just fine ?! Could even handle my test CDR no problem !  :o
Okay, I do remember that I did spend some time fiddling with the laser trimmer to try to get it to behave as best it would... but I can't remember that I managed to get it working 100% right.... otherwise why would I have ordered a replacement CDM ?! I Think I losing it...
Checked the eye pattern, got almost one Volt. Not not bad for a 30 year old player, and plenty enough in practice to read CD's just fine.

But, I replaced the CDM anyway, if just to see if the "new" one, that looks even more crusty than the original one,  would work at all.
It does work, and the eye pattern strangely, is 100% the same amplitude. Player behaviour too. It's like I did not replace it.... so I left that "new" CDM in place, and will keep the original one in a safe place... the CDM is common place so it will probably be handy one day...

However a new problem arose while I was testing the bloody thing : somehow I now had sound coming out only of the left speaker, nothing from the right speaker !  |O

Turned out to be a break in the audio cable... yes, this player is so cheap that it does not even have RCA audio jacks at the back... it's got an audio cable hard wired, sticking out of the player (same for the power cord !). I HATE hard wired cables, a pain !!!  :--
It connects to the motherboard via a little 4 way connector.
If nothing else, I needed female to female RCA adapters so I can plug that cable to my test cable that goes to the amplifier ! A pain ! Of course I don't have such genre changers.. so I made some up, using RCA jacks I had laying around, salvaged from god know what... they have funny colours to them, must be video jacks not audio, but who cares... it works well enough...

Removed that connector, cut 10cm worth of cable to get rid of the break, soldered the 4 wires directly to the motherboard where the connector used to be... yeah I know it's crap... but I wanted to get this thing to work right now, and for as little money as possible... it's super crap layer and I have zero remorse sorry !  :-//  There is obviously a beefy strain relief plastic thingie that clips in the chassis, so it's OK....

So, that player now works fine, I can put it up for sale !!!   8)


Next. This evening I received the belts for the Sony changer... new loading belt is much skinnier than the one I put... but it's conform to the original, so I tried to trust it...
Glad I did. Tray and  clamping mechanism now work perfectly, and even better : the PLAYER / changer now works like a charm ! Carousel works just fine now, this mysterious problem that got me to pull my hair out, is GONE !

Unbelievable...  a (very) tight belt was enough to  take the loading mechanism to a crawl and also induce weird problems with a mechanically unrelated carousel ! I guess the loading mechanism being so weak, caused many timing issues that confused the CPU, did not know how to handle them.

Lesson learned !  That was an interesting repair then, glad I did it !  Now I know what a tight belt can cause ! Was also fun going to town testing in detail the two optical table sensors, analog and digital. Also, taking the encoder apart.

So that's great !  :D

But.... I still have 3 lesser problems :

1)

Player can read a pressed/ normal CD just fine, but no joy whatsoever with my test CDR. Sadly as the manual states that you can check only check the eye pattern, but that there are no adjustments provided ! So that's too bad. I will just have to accept it and carefully NOT talk about CDR compatibility when I put it up fr sale....
It's funny though, that this ONE modern player, marketed in 2001, only modern one I have... is modern enough to be CDR "enabled"... yet it can't handle them... whereas alllll my other players, which are 10/12 years older, can ALL read my CDR jsut fine even though they are not supposed too !  :-//
I guess it only foes to show that yet again.... newer does not always mean better....

2)

The track selection rotary encode on the front panel that's playing up.... can't possibly sell it like this. Need to have a closer look at it. Hopefully it's not sealed and I can spray some contact cleaner in it... or else I would have to take it apart or drill a tiny hole in it... but I have never done it, so hoping I won't screw it up  :-[

3)

Even more annoying, see this short video clip I made,  a mechanical problem with the tray :



It makes a horrible noise when it closed (it's fine/quiet when opening).  Looks like the gear that catches and drives the tray, has problems catching the track underneath the tray.

I don't know why... all these gears in the loading mechanism are quite beefy and in perfect shape, not damaged teeth what so ever, and it's all greased.
At first I though OK that's because I did not put back all the screws that secure the metal brackets that keep the tray in place on both sides... so I put back all the screws.... but no change, still makes the same noise.

I guess I don't understand how to put the tray properly back in place ? It is a bit of a complex mechanism, especially with the " Ex-change" feature, where you can open the tray WHILE a CD is playing...

So I need to work on these issues, then it's going for sale as well...


 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf