ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
Hi everyone
I just got in a CD player that works fine for about 1/2 hour or an hour and then start to run full speed the wrong way.
Then I have to let in cool down do be able to start it normally again.
I checked the output of the servo microprocessor and it seems OK
So I suspect a problem in the TCA372 disc motor amplifier. I have downloaded the datasheet and will check how to test this guy, if someone has already had this problem thank you to let me know.
Voltage should be 10v and I have 9.99 so not the problem.
Have a nice week end
Probably you need to change some caps on the servo board. Which type of CD drive is it?
//Bo.A long list...
Hi BO
Thank you to help me on this one.
It's a CDM 4 ( the comma one)
You mean the one that are around the TCA372 :
C111 - C110 Electrolytics (can do that)
C36 - C98 and C37 - C38 - C97 smd :( (can do but not crazy about it)
There is also the C100 for the laser supply would it be wise to test him too while on it ?
I'd say bad solder somewhere on that servo board first!
Jacques
I would start to change C110 & C111, but also C100. Also as suggested check carfully for bad solder joints or cracked PCB tracks.
Don't forget to take ESD precautions when working on these boards.
Hi
I unsolder the caps and tested them with my capacitor tester.
C100 = should be 47 µF tested at 46.99 µF
C111 = should be 33 µF tested at 33.55 µF
C110 = should be 33 µF tested at 33.25 µF
Does not seem to come from there.
I will try to re-solder everything around the TCA372, checked under the light X5 everything seems OK, but on B&O boards sometimes it is not visible.
chti59:Hi I unsolder the caps and tested them with my capacitor tester. C100 = should be 47 µF tested at 46.99 µF C111 = should be 33 µF tested at 33.55 µF C110 = should be 33 µF tested at 33.25 µF Does not seem to come from there. I will try to re-solder everything around the TCA372, checked under the light X5 everything seems OK, but on B&O boards sometimes it is not visible.
Something is failing under load, getting hot. Maybe solder points or dirty jacks and plugs, clean all jacks and plugs, then disconnect/connect several times.
If you desoldered and checked caps, change them as Bo recommend, you are testing cold, when hot they may fail.
Collecting Vintage B&O is not a hobby, its a lifestyle.
I had CDM4 behaving (hot or cold) like that, it had missing -9v from decoder board.
blah-blah and photographs as needed
Caused by? Probably by broken leads in the connector on the board or missing voltage from the psu?
Maybe originally broken grey lead, leading to burnt tr on decoder board -9 line...
Same here last week with spinning cd from a bc9500. Broken grey lead with burned smd TR on decoderboard.
BTW, ended up doing all grey wires. After the first, the second, third, fourth broke...
Used my ESR meter, first time, had to find it first. it is 1 year now I have it and never used it. Did not read the manual but this is what it gave me.....
results below
ESR 0.61 - C100 = should be 47 µF tested at 46.99 µF
ESR 0.80 - C111 = should be 33 µF tested at 33.55 µF
ESR 0.26 - C110 = should be 33 µF tested at 33.25 µF
below 1.00 they are supposed to be good, but I will change them anyway as 0.61 and 0.80 is close to the limit , will see if anything happens. Just for learning purposes.
And check on those ominous Philips solder joints and grey ribbon cables.
ominous Philips solder joints ??? why philips ??? the board is from B&O No !!! the laser is philips
grey ribbon cables ??? I did not find any grey ribbon cables on the laser boards??? they are black wires hold together with a plastic
Its a CDM 4,
Am I getting lost here ??? or you guys are talking of the other phillips CDM's
As for the caps what do you use as brand : germany lots of ELKO's and some are speaking about Nichicon.
Elko is German for electrolytic I think, a generic term.
The servo boards ARE Philips OEM parts and no manufacturer made their own! Philips used a soldering technique that, two and a half decades later, lead to many bad joints you will have to inspect and re-flow.
A CDM4, okay then.
chti59:As for the caps what do you use as brand
For the lase cap use a blue Philips/BC/Vishay.
http://se.farnell.com/vishay-bc-components/mal203035339e3/capacitor-33uf-16v/dp/1165415
Changed all electrolitic caps with new one's. CD starts full speed and turn reverse right away.
NO CHANGE AT ALL !!!!
I have tested with another servo board and the laser unit is running fine.
I have checked voltage when CD is pressed and testing R112 and R113 gives +10v and -10v as stated on schematics
What next ??? I should give up and replace the board but that would frustrate me.
Idea's are welcome. I was not able to find over the internet someone with the same problem ??? does everyone just change the board ???
Might be cold joint on power supply to CD, resoldering might help
Depending on board version, there are two transistors on the servo board driving the spindle motor.Two 10 ohm (fusible!) resistors work in the same circuit and sits close by.Replace all four components.Note that most service manuals have a typo! (Wrong transistor type).Fit what the factory did.
Martin
Hi martin
Thanks will do that, I checked and I have 3K- on the board so it states BC858B over the internet and luckily my service manual states the same.
On the other board that works I have 3KP but it comes up to the same BC858B
as for the 10 ohm resistor could not find it, I found 2x 4K7 that are connected to the BC858B I suppose it must be these 2.
That will be a first for me to change such small SMD's
I keep you guys posted when parts are received and replaced...
@Orava : Not possible as it works when changing with a working board, so the problem has to be on the board...
What board version do you have ?Photo ?
here it is
Different version from what I was referring to.I'm afraid, I'm not familiar with that version.
OK thanks martin, I keep you posted. Will change the transistors and see what happens...
chti59: @Orava : Not possible as it works when changing with a working board, so the problem has to be on the board...
Maybe you could use coldspray to find out what component is causing trouble, tough it can stress it permanently broke.It still might be power rail somewhere, as transistors what Martin refers are part of it (right?). I had somewhat similar problem once and it was loose wire between servoboard adn mechanism causing burn on those transistors....
Hi Orava
On this type of CD it is only a flex that goes to the CD mech, I have checked the soldering from the flex plug and reflow them as I play around for a while and already stressed it a lot.
As from the 2 transistors yes they are both part of the CD control. they are sold 0.15 a piece so will change them and see what happens.
Before I was unsoldering them and checking them but these SMD's are way too small to play with :o(
Change both transistors today and that thing keeps turning the wrong way...
Damn, damn, damn
Try with cooling spray to see if you can find out which component if failing.
Have to order some, never had to use cooling spray until now.
Well I have to quit on this one and make a board switch.
Tried to cool with spray nothing, swapped all kind of chips cd related from a working board, microcontroller etc...even replaced the decoder with a new one.
Nothing, and after replacing the chips of the non working board to the working one, that board keeps is still working.
I have checked the diagrams many times but my knowledge did not help. Still can be an smd resistor, capacitor, diode but would take too much time.
This post will have to stay unsolved.
Well, it can then be board itself. Some thruboard link or so...
Don't you think that the laser actually can be faulty?
Yes I am shure, as if I take a working cd decoder board (board N°8) from a working 2500, the cd mech. works perfectly.
If I take the defective board to the other 2500 it is also going full speed as soon as we press CD
I know that it can be a challenge to solve the issue. I'm always persistend to solve mine (takes a lot of time,without any doubt not economical).
But if your done with it, I do have a spare board from a BC2500. Came from a working One. So send me a pm if you're interested.
This board tends to have small cracks near the clamps/edges.
Thank you for your reply but cannot find any cracks ont the board.
The unit is still open on the bench and I have to finish it for september (it's for a friend), i will replace the board if I do not find but still will work on the defective board on another unit.
I hate when I cannot find the problem. Sometimes it goes in a box for years and then I go back on it when time.
And this time testing voltage on such a board is very complicated as there is no missing voltage. At contrary there is too much voltage reaching the motor. I have changed all the chips that regulates the power to the motor but I think that the too high voltage coming to the motor is way up somewhere.
You are right with this idea. The regulation of the motor is not the problem... it is the recognition that there is a disc inside and that the focus does not work.
The system of this board is something like a closed loop regulation. If the laser focus does not see the surface of the disc, it either stops or tries to read data, which fails.
But do not try further on this board, i think there is more than some capacitors defect. In the last years i have seen more and more disc controller going defective. It seems, that the chips are also dying...
Well I also have exchanged the chips pulling them out from a working board and resolder them both in the other one, the OK one keeps working and the one not working keep not working.
In the service manual they speak about a disc detector board N° 20 that is supposed to be behing the CD but I was never able to find this board.
But there is a connector N°P62 on the decoder board that should be connected to this N020 board, but it is not connected, neither a loose wire connected to that P62 in the unit.
So may be someone has fooled around with this unit before me, and there should be that N°20 Board and of course when I use another of my boards that does not have the connector P62 the unit works.
So now how can I find out that the N°20 was supposed to be there or not and that someone placed a wrong cd decoder N°8 board in it .
May be it is possible to find it by the type number but only B&O will be able to reply that question.
Or may be someone can confirm what I suspect and explained just above.