The Workbench

Re: Fuse problem with Beogram CD-X

jvezina — Sun, 04 May 2008 20:41:20 GMT

Finally the problem is solved and was trivial. A 400 mA fuse is required instead of 200 mA as my CD-X runs under 120 Volts.

I purchased it in France in 1986 and the conversion to 120 Volts was made by a local B&O technician. Clearly, he has forgotten to replace the fuse with a 400 mA one, as I discovered in the service manual (half the voltage, twice the amperage). Ironically, the player worked properly for over 20 years with the 200 mA fuse.

I nevertheless gave a look at the power supply and what appeared to be an electrolyte leak from one or more capacitors is just glue used to secure the capacitors in place. All caps tested good. I reassembled my CD-X and played several CDs and everything is fine.

Best regards,

Jean

Re: Fuse problem with Beogram CD-X

jvezina — Sun, 02 Dec 2007 22:02:46 GMT

Many thanks to all!

I will keep you informed of my progress!

Regards,

Jean

Re: Fuse problem with Beogram CD-X

solderon29 — Sun, 02 Dec 2007 11:45:19 GMT

Very reliable machine,basically a Philips CD104.

If the fuse blows violently,and goes black,be suspicious of the filter caps 2701/2703.Also,the mains switch may be arcing.

The actual transformer may be shorted turns,but this is unusual with this machine.

Leaking psu caps don't normally cause blowing fuses in a conventional designed supply.Check the various electrolytics on the psu pcb with an ohmmeter,for shorts.Be suspicious of the bridge diodes though,particularly 6459,6460,6463,6464.

Re: Fuse problem with Beogram CD-X

auric — Sun, 02 Dec 2007 01:58:22 GMT

The CDX is 20 years old. Can't say that blowing fuses is a "known" problem as mine has functioned perfectly nearly all this time.

Your first clue is the leaking electrolytic! Stop, do not proceed until you've replaced those caps. You can stress the "rest" of the power supply out replacing the fuse and powering the thing back up with a short; notably the regulators could be come damaged.

I don't have the schematics with me at the moment, but you should be able to uncouple the rest of the CD player from the power supply. When you've done that (after you've replaced the electrolytic) try to power it back up to see if the fuse goes. If it does you know the problem is in the power supply. If all is well and the voltages measure up then plug the rest of the electronics back in and try again. Once you've fixed the problem, replace all of the electrolytics especially in the power supply as its probably about time. The CDX runs very very hot and over time the caps get nice and cooked.

A couple of things that you should know about the CDX

1) The glass control panel is glued to the body mostly likely with double sided tape. While mine has held just fine, there is a possibility that the adhesive might be going so when moving the deck/flipping it upside down etc... the glass panel could come out and become damaged. It would be a good idea to tape the glass down just in case.

2) There is a metal rod inside the deck that is responsible for flipping the CD tray up. This rod rests on two very very thin and fragile plastic supports that are molded to the plastic body of the CDX. If not properly aligned, they could snap off. Be very careful!

3) A few years ago my CDX started acting up with intermittent play issues. The problem was traced to cold solder joints. While you have your deck open you may want to spend some time reheating all of the solder joints to make sure things are solid again.

4) Finally while you have the deck open you should apply some lubrication to the gears in the lid mechanism as it is likely dried up. Take care not to get any on the belts otherwise the lid will not open properly due to slippage! (If belt is loose or cracked, now is good time to change.

Derek

Re: Fuse problem with Beogram CD-X

jvezina — Sat, 01 Dec 2007 20:13:48 GMT

solderon29:

Are you technical,and do you have a service manual?

Yes, I have good knowledge of electronics (I have replaced 50 capacitors two years ago on my MX-5000) and I have also the service manual. The first thing I am thinking to check is the power supply. I will test first all the large electrolytic capacitors to see if they have become out of spec. One of them seems to have leaked electrolye. I don't have time to check voltages because a new fuse lasts for about 1 minute, but the player works properly during that short period.

Thanks a lot!

Jean Vezina

Re: Fuse problem with Beogram CD-X

solderon29 — Sat, 01 Dec 2007 10:04:37 GMT

Are you technical,and do you have a service manual?

Fuse problem with Beogram CD-X

jvezina — Sat, 24 Nov 2007 22:50:49 GMT

To all:

My Beogram CD-X which was working properly until recently now no longer works after resting unused for a period of two weeks. The small 200mA fuse which is located on the PCB where the mains cord is connected now burns. I have tried a time lag fuse and the CD-X works for about 1 minute and the fuse burns again. A fast acting fuse lasts 1 second. Replacing this fuse is annoying as it is soldered.

Is this a known problem ? I am suspecting the large electrolytic capacitors on the power supply board.

Thanks,

Jean