yachadm, Die_bogener, Dillen ... >>

Maybee i wasnt clear in my post, sorry guys!

I read a lot of your replies at this workbench forum, i know you all are experienced, and you should know i really admire you are doing repair on component level, and i totally agree about upgrading to better spec capacitors.

I just wanted to share my experience with a quite similar problem. It was easy solved, and was quite inexpensive, that was why i thought it was worth considering.

Steffen>> Do you mean the laser unit, not laser lens ? I have good experience by replacing wit VAM12xx types, but it is important you are getting the right one. The one for the CDpro has got a metal shield mounted on the pcb at the laser, the one for the CMD12ind has got a TDA1302T ic on the pcb and no metal shield. It is easy to find very detailed pictures online so you can compare them

Regards

 

kumse:

Steffen>> Do you mean the laser unit, not laser lens ? I have good experience by replacing wit VAM12xx types, but it is important you are getting the right one. The one for the CDpro has got a metal shield mounted on the pcb at the laser, the one for the CMD12ind has got a TDA1302T ic on the pcb and no metal shield. It is easy to find very detailed pictures online so you can compare them

Regards

 

That's what I meant: laser unit, ofcourse. And -thank you for the reply.

And to Dillen>>Yes -I've read the rest, and know that you can fix it with a Post-it note I was just asking - theoretically -what if it can not be fixed this way..?

Steffen

Steffen,

If the Ouverture laser lens is blocked, the blockage will have to be removed somehow. If a corner of a post-it note
cannot do the trick, some other means of cleaning will have to be figured out. It's tiny flakes of chrome or similar
that are stuck on the voice coil magnet so can be a bit difficult to shift.
If the laser is dead, it will have to be replaced (I've never had to do this).
If it's just starved for current (as usual), the focus is off or the cats eye pattern for some other reason is skewed, the
reason will have to be found, usually dried out capacitors.

Martin

I've just got the BeoCenter 9300 in for repair from a customer in the Caribbean.

As with Clive's unit on the previous page of this thread, this is a later 1997 model, with the SMD capacitors on the CDM12 CD PCB - the SMD electrolytics on the upper side, and SMD tantalums on the underside.

And as with Clive's unit, the big 330uF (C2000 5VDC rail) and 100uF (C2001 9VDC rail) are both inflated. I will replace all the SMD's, with leaded (non-SMD) units.

Interestingly, the famous decoupling cap for the Focus Motor (C2103 IIRC on all the older CDM2 and CDM4 models) was a 33uF. Martin had wisely suggested an upgrade to 47uF, and here we see confirmation of this. On this PCB, C2003 is the 47uF decoupling cap for the Focus Motor power supply!

The 2 blue axial Philips 10uF/63V to the right of the relay, are both shot, showing about 26uF with 7.6ohm ESR. The other caps, mostly Elna, but with a couple of Samwha's thrown in for good measure, are pretty close, but many are pushing their upper ESR limits, so I will replace them with Panasonic EB and Wima MKS2 series.

One of the solder joints of the big C29 6800uF/16V cap at the extreme right of the PCB, has separated from the adjacent traces, so that will be a minor repair.

However, I have a question relating to the power supply / power amp PCB.

Directly to the left of the 6800uF cap, is C30, a 10uF 50V cap.

In the circuit diagram, that same C30 is shown as a 2200uF cap, with print space on the PCB hinting at a large cap which is supposed to be there. I checked through the documented changes from the first CDM version, to the CDM12 (this one), and can't find any reference to deleting the 2200uF cap. On my own BC9300 (a 1994 model, the 2200uF cap is there). Has anyone seen this before?

Menahem

Yes, i have seen this before with the missing 2200uf cap. The cd drives are different, one power supply voltage line is not used any more. So the cap is not necessary any more.

I dont remember which voltage is gone, but i have had both types of the BC9300 in repair. The older drive had the cap, the newer drive did not.

Was it the negative -9V line...?

Very good Martin!

Close enough - it was the -12V line.

The 6800uF services the +12V line.

Menahem

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Clive where you apply to fix this problem?

I have exactly the same problem in my Century. And it has the exactly same CD PCB.

I have changed all the SMD electrolytic caps on it, with regular feed through caps, but it didn’t help. On my board also the two biggest SMD caps (330uf and 100uf) where clearly damaged.

I also cleaned the laser couple of times just to be sure its clean. I tested both motors with DC supply and they are working great. There is also nice visual laser and focus seems to move clearly.

The service manual of Century doesn’t have the layout for this kind of PCB. So it is making the fixing a little bit more difficult.

If you did find some specific component to be damaged let me know. And if anybody has good ideas let them fly.

Pete

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Hi,

I am glad to answer to my self. I got this fixed the laser was bad. New laser did the job. I toke the laser from CDM 12.4, very cheap and pretty easy fix.  

Now to fix Beolink 1000.

Cheers,

Pete (Finland)

I am trying to repair a 9300 linear cd, withe same board pictured in this thread. I have changed the laser assembly and am having some success but the current behaviour is a bit puzzling. I have been able to play a disc but only twice, the rest of the time the laser reads the disc for a couple of seconds and then stops. Once the disc is playing I have been able to skip through tracks, but once stopped it goes back to the erratic behaviour and is unable to read the toc.

I am about to change the 6 large caps on the servo board, should I consider changing the tantalum caps on the other side? What considerations should I have when choosing replacements as far as quality is concerned?

I have two more pics which I think show damage on the board which may be relevant, one is what looks like damage next to a cap, and on the other side of the board the TDA7073AT on the right is loosing the print, is this damage from heat?

 

 

Heres the chip one.

Just replace these 6 SMD caps, that's all. Dont worry about the tantalum caps, they will have no problem.

Martin

Here's one which I did, with regular leaded capacitors instead of SMD replacements.

I use Panasonic EB, Nichicon HE, and the blue one is a Vishay BC 150RMI.

All are 105 degree caps for extra-long life, and you can use any or all of these on the PCB for guaranteed operation.

If you insist on using SMD caps as replacements, the Panasonic FK are quite suitable.

Menahem

Thanks for that. I will use 105 degree and I'm not planning on SMD caps. Incidentally I can't see any pic with your post, would be very interested in seeing the finished result.

Do you think I'm on the right track as far as solving the problem is concerned, or could I have other problem areas to look at?

 

I managed to recap the servo board, which I found easy thanks to the tip on removing the original smd caps (twist them off). Sadly this did not fix the problem and I now suspect the motor (apparently these were prone to failure). Anyone have a european or UK source for these?

Try to clean the round steel guides of the laser head. Use a very fine oil and remove all dust/dirt.

I'll give that a go tomorrow. I have replaced the laser so that bar is definitely clean, do you think it could be lacking oil/grease?

Yes. There is a plastic/bronce bushing guide inside the head. Without some oil/grease it becomes sticky. Clean it first with some alcohol, then use a fine oil. I use a oil for lock cylinders of doors.

I tried that this morning no improvement. The head is linear, and the guide rail has been recently removed and replaced as part of the renewal of the laser head assembly.

The disc now reliably spins for a couple of seconds and stops, and has not read the toc since it was recapped. I am trying to deduce the stage it is reaching before failing and it seems that :-

It establishes a disc is present

corrects focus height

spins disc and attempts to gain tracking.

this is the point where it fails, so it could be :-

failure in tracking logic or insufficient spin speed to successfully track.

 

I'm now looking for a motor!