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
Hello ,
First post here so I'd like to say hello.
I'm a one man repair setup in Bristol Uk , specialising in vintage hifi and studio equpment repairs , but will work on pretty much anything from a food mixer to a SSL mixing console :)
I have here on the bench a Beocenter 9000 Type 2501 , with the cd player problem I have seen on this site , cd tries to load , spins up , door opens.
So I have replaced the C2103 with a NOS Philips 33uf but its 40v see pic.
But no joy , so I have swopped out the laser (entire mechanism ) from a known working CDM4/19 as I read they are the same , but still the same .
So I have been searching for a service manual for the CDM4/24 servo board so I can fault find out of the machine but have had no luck.
I am now a bit lost as to where to go next so I though I'd reach out and see if anyone here had any ideas.
Many thanks and good to be here
Dave
Welcome to Beoworld Dave.
I can recommend upgrading your membership,as this will give you access to service info such as manuals and product info,if you are not particularly familiar with B&O products?
The technical info for the Beocenter 9000 cd player was a supplement to the main manual,and as such is very rare.However,the Beocenter 9500 is very similar to the BC9000,and the manual has full info on the cd section,and also how to use the "self test" system employed.
The symptoms you describe are indeed in many cases due to the failure of C2103,but of course they can be caused by other failures too.The fact that you have replaced the cd mech (inc servo board?)with one from a working machine,suggests that your problem is elsewhere.
The large pcb with heatsink in the base of the Beocenter carries not just the cd decoder,but also it's power supply.You need to investigate that all the supplies are available at the cd mech,but also you will notice that the same type of capacitor (Philips)is employed in the decoder too,and can be just as suspect.
The plug in connector looms between the decoder and cd servo pcb's are also notorious for becoming intermittant with age.
Keep us posted,and good luck with your venture sir.
Nick
Hi Nick ,
Many thanks for the information , I am a silver member so do have access to the service manuals :)
Justy grabbed the service manual for the 9500 so hopefully the cd part in there will get me where I need to go . Thanks for pointing out that the cd info is in there.
I only swopped the laser mech and its servo motor not the whole cd sub assembly , so servo board is the original.
I'll keep updating as we go
cheers
So , I have the servo board out and the laser test circuit attached and we are getting 2.2v with the switch open , but 4v with it closed so definately an issue with the laser supply , I guess I've burned my new laser I put in , nevermind a lesson learnt :)
Also when I try to preset the laser current as in the service manual to 1k ohm I can't get any where near that high , so I'm thinking maybe an issue with the TDA 5708 ?
The quest continues ....
Update , note to self ,remove test circuit before you try and set the 1k ohm laser current .
Needless to say I now have 1k across R3105 and R3106.
You've gone quiet sir!
Have you had some success with the BC9000?
Its nice to be missed :)
Had a few other pressing jobs on , but we have a little success in that I've successfully tested the laser output voltage from the servo board using the test setup as in the BC9500 service manual and am getting 2.2 vdc with the switch in both positions and the led goes brighter briefly while the feedback system catches up so the servo board I declare all good .
I now move towards the decorder board but not really sure where to start testing as tracing output from the laser will be impossible as it won't play a cd .
Any pointers would be great , also anybody know where I could get hold of the test cd that is stated in the BC9500 service documents ?
Don't get too technical yet.If the disc spins but stops,it suggests that the optic's are basically working,but the laser may me too low power to establish a good data stream?
This is where C2103 is so culpable,as when it becomes low value,the laser beam becomes unstable,and so the data produced is corrupted.The decoder then goes "doh !",and shuts down the system.
If the wiring looms between the servo and decoder boards become intermittent(notorious!)the same symptoms can appear.
You need to establish that all power lines are good and stable of course,but you will notice that the same blue Philips capacitors are employed in the decoder too.I alway's change these too while I'm in there.
Thanks for that Nick ,
I have replaced C2103 , with the NOS part pictured above , would it be a problem as its 40v ?
I have re checked the voltages and they are good and stable .
I have checked the wiring looms between servo and decorder pcb's (with much jiggling whilst testing ) and all good too.
One thing I forgot to mention is this , if I press cd to try to start playback , mecahnisms stops , door opens , if I then press load cd , door begins to close , the disc spins up and the laser has power , and the display reads 0:00 but it will sit there spinning until I stop it , the cd doen't play , its as if its in a pause .
May be un related but thought I'd mention it.
Thanks for all the input
The voltage rating of C2103 is not that critical I imagine,but the original was 33uf 16v.
Although it's a NOS part your capacitor is after all 37 years old,which although it's "virgin"has still been subject to aging!
These caps are available new made nowaday's by Vishay to the original spec.
As it's so critical to the operation of the laser servo,it might be worth replacing it again ?
Yes , next stop is replacing again , I've found the Vishay equivalents ones at Farnell so have ordered them , and as I had to make up the ££ for free delivery I'll be replacing all the axials on the decoder too just for good measure.
I did think I was pushing it with a 37 year old electrolytic , most likely all dried up , allthough it did test all well with my Peak esr / cap meter .
But I realise that may or may not mean it is functioning as it should in this circuit.
Many thanks again will update soon all the caps arriving tomorrow
So caps arrived and are in , but still exhibiting the same behaviour , spins up , stops and the door opens .
these are the said caps : https://uk.farnell.com/vishay/mal203035339e3/cap-alu-elec-33uf-16v-axial/dp/1165415#
I replaced all the axials on the decoder board also.
hmmmm ...
Can you 'scope at 31IC6302(SAA7120)pin 26,at start up? This is the HF signal feed to the decoder.You won't see a discernable signal,but should see some activity as the laser servo tries to find focus.If there is no activity you need to trace back to pin 27 of the laser servo input processor 30IC6101 on the servo board to see if there is anything happening there?
yes indeed brief activity is present , I am getting a brief saw wave looking waveform , then a brief shot of dc @ 3.64vrms before it shuts down
So , with much more probing and 'scopeing , still none the wiser . There are definately signs of life on various pins at start up on the decoder board but none are really looking like what the service manual would suggest.
I'll make some decent notes and readings and update further soon .
Can you carry out the testmode procedures offered in the manual?
You can check that the radial and focus servo's are working.
If the radial arm is sticking or it's foil connecting cable is fouling somewhere,the system won't be able to read the disc at startup!
I went through the test mode quite a few times today , very odd results . Its not behaving as in the manual at all. The tests select ok but it appears no testing is going on , the cd spins up , radial arm tracks into the center , I can hear the focus motors doing something but there it sits merrily spinning. The display doesn't indicate a pass or fail.
I'm thinking maybe the laser is a goner ? I know the power supply to the laser is good from previous testing.
So finally back at the bench , and we have a working laser .A very rough and rugged test was done using an old iphone 4 camera to look and at the laser and I can definately see the laser powering up then shutting off . So more fault finding to do , but its not the laser , well could still be but less likely .
More oddness going on , the 9vdc and the -9vdc supplies to the servo board are now coming in at 11.76v , so now looking at the psu , but the 9v rails appear to be unregulated according to the schematic , but i may be wrong . ? so I am wondering if the 11v I'm getting could be ok. Either way its bouncing all over the place on the minus side not stable at all on the Focus / Radial Motor Amp pins 9-16.
Tested electrolytic caps on the decorder board in the psu area and all good , so next stop I'll test the voltage regs and zeners.
I feel i'm making progress :)
Hi,I am joining in here.
This is my first post here, but I have an almost identical problem to you.My unit is the Beocenter 9000 Type 2501 purchased in 1987 in Denmark.
Initially my CD door closed, CD started spinning, CD stopped spinning and CD door opened.I have then replaced the 2103 capacitor with an 33uf 16V, although not identical in appearance as the original one.
Now my CD behaves the same way as you describe:
CD door closes, CD starts spinning, It recognizes the no of titles on the CD, the CD keeps spinning, some times not progressing, other times it can start to play but very erratic.I can often also shift the to the next title.You can hear the CD drive is working a lot to maintain the data stream.
Do you think it might be as simple as replacing the 2103 capacitor again to the correct type?
I was trying to post a photo of the capacitor I installed, but even though I have uploaded the files to my Media, I can't get access to them when posting?
Max: Do you think it might be as simple as replacing the 2103 capacitor again to the correct type?
Hundreds before you have found out, that this capacitor is critical and we've had numerous threads about this subject, but of course you are free to try a couple of wrong types first. It has to be a certain brand/type to guarantee correct function for more than a short time. Prerably a blue Philips/BC axial, which is also what I use and it works every time.I can supply capacitor kits for most servo board versions, containing correct capacitors. PM or email me.
Don't be tempted into messing with the adjustment trimmer(s). It will only make things difficult to get right again and may actually do permanent damage to the laser.
Martin
Hi Max ,
And welcome to the forum.
You have so far got a further than me . My cd still does not recognise the disc , not reading the TOC etc.
I beleive from reading you need the correct type of capacitor , they are manufactured by Vishay now I did put a link to them in this thread and there are capacitor kits available on this Forum .
So far I've re capped the servo board , redbuilt the power supply on the decoder board and recapped all axials and check all interconnecting wires , and still not working.
The voltages are better on my machine but still not great so some improvement but still work to do.
As far as I know you use the insert media button to put photos in your post.
Hope that helped a bit ,
Cheers
Hi Dave,Thanks for your reply.I have now emailed Dillen about the capacitor kit.Regards
Max
Hi Dillen,
Thanks for your reply.
I have sent you an email about the capacitor kit.
Regards Max
So its been a while , but we have just played a cd successfully , much more checking to do , but finally the door stayed closed
All is well , playing cd's without problem .
It turned out to be something of a dry joint or similar on the decoder board , I reflowed all the solder points on the board and after that all came back to life. I had previously rewired the harnesses between the decoder and servo pcb's but that did not help .
So thanks to everyone for the input and assistance , much appreciated .
Case Closed.