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
Thank you for the advice and guidance that helped me repair my Beogram 5000. Now it's the turn of the Beogram CD-50. There are two obvious issues which I need to tackle first and if I'm lucky that will be all that's needed.
Problem 1 – Blown CapacitorOne of the film capacitors on PCB 1 “Display and Key Control” exploded (see pics). It made a nice bang with accompanying puff of smoke but in the process blew itself apart so I can't read what the value is. Sadly there isn’t a pcb layout in the service manual, just a schematic, and without removing the pcb it’s not obvious which cap it is. There are 35 caps on this board. Does anyone recognise which one it is, and also recommend a good match to replace it? Ideally I’d like one of the same or similar size. I don’t think it did any other damage when it exploded, but I guess I will find out once it’s replaced.
Pic 2
Problem 2 – Disc Drawer ObstructionThe second problem is that the disc tray won’t retract fully. It appears to be jamming on the Lower Disc Holder (see pic). I have no experience of this item so I can’t tell if it’s broken, but the inner part of component 9132 seems very loose. Is it meant to be this way and am I just being daft?
The exploded cap is a Class X2 suppression capacitor.It's a safety component and it MUST be replaced with one of the same type.
Martin
The CD clamp must be lose to be able to align and center itself when a disc is clamped.
Dillen: The exploded cap is a Class X2 suppression capacitor.It's a safety component and it MUST be replaced with one of the same type. Martin
Noted. Thank you Martin. Would you have any idea what the values of this particular cap is?
Thanks
Nick
10n or 20n or so.It's likely to be the only cap sitting right across mains.Look it up in the servicemanual!
It is indeed a filter cap,and they seem to "spontaneously combust" for no reason it seems.
I have a spare one you are welcome to that I salvaged from a scrap pcb.
The tray problem is almost certainly due to incorrect timing.It's easy for the tray to "skip" a couple of gear teeth when pushed in while loading etc.
We all have our own preferred method of getting the timing right,but you will need to remove the laser etc mech from the main chassis,so you can see whats going on.
Dillen: 10n or 20n or so.It's likely to be the only cap sitting right across mains.Look it up in the servicemanual! Martin
Thank you for directing me to the correct part of the circuit Martin and please understand I wasn't trying to be lazy. I am a novice and really don't want to make a mistake.
If you don't mind I'd like to check I have tracked down the right component. I think it might be the one circled on this section of the schematic for the power supply i.e. component C28 listed as part 4130351, 10nF 20% 250V. Can someone tell me if this is right?
Thank you.
solderon29: It is indeed a filter cap,and they seem to "spontaneously combust" for no reason it seems. I have a spare one you are welcome to that I salvaged from a scrap pcb. Nick
Thank you Nick, I would certainly appreciate the salvaged cap. I can PayPal you some money for the component and to cover the cost of postage. Should I send you a PM with my address?
SurreyNick: Dillen: 10n or 20n or so.It's likely to be the only cap sitting right across mains.Look it up in the servicemanual! Martin Thank you for directing me to the correct part of the circuit Martin and please understand I wasn't trying to be lazy. I am a novice and really don't want to make a mistake. If you don't mind I'd like to check I have tracked down the right component. I think it might be the one circled on this section of the schematic for the power supply i.e. component C28 listed as part 4130351, 10nF 20% 250V. Can someone tell me if this is right? Thank you.
Yes, that's the one.
I'll sort out the part,and get back to you.
The good news is I have replaced the X2 suppression capacitor and the Beogram powers up fine with no apparent problems. I have also managed to get the CD tray back on it's tracks and it retracts fully now too.
The bad news is however that the CD tray won't go in and out under it's own steam (I literally have to pull it out and push it back in) and it doesn't play either I will browse the forum threads to see if there are any clues what I need to do to fix this, and if anyone has any suggestions they will be most welcome
Maybe this can help https://archivedforum2.beoworld.org/forums/t/628.aspx?PageIndex=4
Collecting Vintage B&O is not a hobby, its a lifestyle.
OK. The belt definitely needs replacing but I also need some help please to set me on the right path to identify and correct the other fault(s) that need addressing.
When I plug in the unit and switch on the power the unit is silent as I would expect. When I press 'play' there is a whirring/humming sound but I can't pinpoint exactly where it is coming from, but the disc motor won't spin and I can't see any other parts moving. The motor does spin very easily by hand though and is not at all stiff.
There seems little point in going to the trouble of replacing the belt if I can't address the disc motor issue, but nor can I find anything in the service manual to help me track down and correct the fault.
Can anyone help please?
What you hear when you press play is almost certainly the loading motor,but because the belt between it and the loading mech is slack,nothing else is happening?
The loading cycle is crucial,and there are sensor switches on the mechanism that monitor what state it is in.None of the other servo's will function until the disc has fully loaded.The microcontroller will then turn on the laser and begin the process of reading the disc etc.
You need to replace the belt of course,but you will probably find that the loading mechanism is all gummed up with solidified old grease too.You need to strip the mech down,clean and relube,and clean the sensor microswitches.
If the above seems daunting,you should be able to load the disc manually by turning the large gear,that you can reach at the back of the mechanism until the disc rises and is clamped onto the disc motor hub.
Pressing play now,providing that the laser is ok,should produce some action,and the disc may even play too.
If it does,it will give you the confidence to carry out the fiddly work above.
It's worth the effort,they are underrated machines imho.
Ah. I think I understand and that makes a lot of sense. The belt has completely perished - I found a section of it underneath the large cog wheel. Bearing this in mind should I expect any action at all? I have been able to manually load a disc and I believe it is clamped onto the disc motor hub, but there is still no action on pressing play.
Fingers crossed this is exactly as it should be, because I'd really like to get it working.
I doubt that the disc will be fully clamped with an old belt.
What’s more, there is an end of cycle leaf switch that won’t be operated and nothing will work at all.
First things first, replace the belt!
Jacques
Thanks. Belt ordered. I will report back once it's fitted :)
remember to load the cd upside down
Sorry for resurrecting this old thread, I found it very useful, thank you to the OP and all contributors.
I have a similar issue in that R500 1ohm 1/2watt resistor keeps blowing which I think is down to the same 10n part which had blown in the OP's post. I've tested the diode bridge rectifier next to the resistor burning up and it tested out fine.
Could anyone please help to source a known good C28 power cap in question?
C28 wouldn't have any influence over the main machine.It's a filter capacitor,which in combination with the series chokes on the mains input/cpu board forms a network to prevent interference from the machine reaching the power network.
The safety resistor that is failing,is there to protect that section of the supply if too much current is drawn.
You need to investigate that supply further.It's the components near to the suppressor C28.The small electrolytic cap and the power transistor on the adjacent heatsink,ar e part of the supply to the interface upc.It looks as though that capacitor has been replaced?Is it the correct voltage rating,and connected in the correct polarity?
What Nick just said. C28 is a suppressor capacitor, not related to the symptoms you describe.Check C349 and the rectifier.
Thank you for your reply.
I did establish that C1, the small electrolytic cap was faulty so replaced it with another 100uF 25v electrolytic cap as per the service manual and have replaced the power transistor on the heatsink as you describe but the original tested out fine.
I will investigate C1 further as this seemed to be the point which R500 started burning up.
Thanks again.
Sadly no dice yet, replaced C1 to no avail.
Checking the D316 with a DMM diode test checks out as it should and I have replaced C349.
Stumped.
See if you can disconnect L1 on that pcb,this will disconnect the upc ic.If the safety resistor then doesn't blow,you have isolated the problem.
Test the upc supply with L1 disconnected,there should be 8v at the emitter,and 5 volt at the collector.
If the supplies are correct,it will suggest that the upc ic is short circuit.
There is another cap in the supply(C4) which might be culpable,but it's inside the can over the upc ic.
Thanks Nick, which transistor should I measure from with L1 disconnected please?
If TR2, the transistor on the heatsink, I measure 11.9v at Emitter and 5v at collector.
As a precautionary measure I replaced C4 with new identical capacitor.
Sorry,yes I meant TR2.The input voltage at nearly twelve volt's seems a bit high,but I imagine that's because the output is unloaded with L1 disconnected.The 5 volt output is the crucial one though,and that seems to be ok?
The safety resistor doesn't blow with L1 disconnected?
It's beginning to look as though the upc has failed sadly.I've come across this before!
I may have another pcb among my salvaged treasure,I'll have look.Otherwise,you may be able to find another CD50 to be a donor?They seem to crop up at sensible prices these day's,particularly as for "spares or repair".
Thanks Nick, such a shame.
i’ll keep an eye out but may just move on to a better model. If you come across this PCB please let me know, happy to Paypal you for it!
Yes indeed,these are nice machines.I'll have a sort through my salvaged bit's n bob's.
Please don't scrap it yet.
Thanks again Nick, will await your reply, be good if you have a spare going to get this one up and running again
Thanks to Nick, this one is operational again, must have been a dead IC but glad Nick could send me a replacement, top notch.
Sadly, while the new board has now restored power, the output audio is very distorted.
I have cleaned the lens and replaced three caps in the muting circuit common with no sound/distorted sound to no avail.
Any other common component which affects both channels to look out for?
EDIT: scrap that, input on amp to CD is the problem, all good on another input, CD player is good.
Is it an analog distortion? I.e. not the high pitch screeching/whining digital fallout kind of noise?
Everything from the DAC to the output is common. Even the DAC itself is multiplexed...
Hi fellow B&O users,
I just had a problem crop up on my CD50. It was working, then I opened to blow out some dust and add a drop of sewing machine oil to the two gears that run on the flat slide. Putting it back together, now pressing PLAY the disk loads, then comes out again and repeatedly closes and exits, again and again, non-stop. Taking the cover off again, it seems that the spindle motor is not spinning when the CD is in the upward loaded position, then drops and exits. The two gears which I believe move the "head block" seem to be frozen in place. The head does not move and the cd does not spin. Help Me.....
I really did not do much more than dust and apply minimal oil!
I never imagined that this set would be so very finicky, I would have left it alone!
It's a recent acquisition, but was working fine, even played CD-R's.
Steven
Steven L. Bender, Designer of Vintage Audio Equipment
Welcome to Beoworld!
No idea what your problem is. I've had mine for years after restoration and it's proven very reliable.
Perhaps the clamping system is badly adjusted.
There's plenty of information here about this.
Happy reading!
Damaged contact for the loading tray, dirty or damaged disc sensor or wrongly sync'ed gears.The latter will be my first guess, hearing that the thing was taken apart.And don't use sewing machine oil for the gears. It's way too thin and won't work together with the original stuff.Sewing machine oil is for metal-metal workings.Use white lithium grease as B&O did.