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
I have never posted here before but I have found this site very useful over the last three years.
A few months ago I collect a box with two CD50s in bits. Having never actually seen one beyond the world of pictures, I was in shock, someone had being doing major surgery, wires everywhere. But no that is what the CD50 is, in bits it was a nightmare, what to do?!!! The obvious solution was to buy another which was complete, except it had been dropped and needed knocking back into shape, but that was simple compare to what was waiting. It turned out to be one of the first versions, I decided not touch any of the electronics besides straightening out the front.
The second is from 1987. I change most of the caps checking all of them as this unit was dead. Nothing blown in the caps but they were mostly at the low end of tolerence. I found two dead diodes, one dead transistor and a short cause by a factory mod on the back of board 7 transistor leg shorting to wire underneath, plus a crack in a solder joint off of P109. To track all these faults down took some time as this was my first look at the interior of the CD50. I did wonder if it was worth the effort. When I finally plugged it in and it worked I had to double check to see if I was actually using my test speakers.
The difference between the untouched CD50 and the one that had a major recap is like a blunt knife that has just been sharpend, incredible. I guess the real test will be the third CD 50, thats virtually the same as the second CD50 I fixed. I'm going to play that before recap and see how that compares.
A couple of things before I must go! zip ties if you can find one that measures 4.9mm its more accurate for setting turntable height, easy to slot in. I found to much room for error using calipers.
I do have a question, when I press stop there is noise in the speakers when the disc is disengaging, also when engauging at the start, any ideas where the problem is?
Funny thing board 8 on the third CD50 has the same shot transistor as the second CD50 I repaired. It has a 10uf cap on board 7 that blew out through the bottom, hard to spot.
PS this is just training for a dead CDX
I'm looking at the service manual adjustments section. Where it says "Base of 8TR336 (8R398) must be short-circuited with chassis", do you connect 8TR336 & 8R398 and short to chassis?
This is a question about Focus Bias 2 and the eye pattern. I must being doing something wrong here. I connect to 7TP6 and ground on the chassis and I end up with the Alps and no eye pattern. I tested two CD50s and have the same result. I tested a Pioneer CD player, no problem the diference is Pioneer give a specific pin to ground to, is there a simiplar pin I need to connect to on board 7?
Well its 0 from 2 so far, 0 from 3 is over and out.
Welcome!
I don't remember the specifics, sorry. But 3 CD50 at a time
Brave man. I hope you can make a mint one out of the three!
You should perhaps register as a Silver or Gold member to download the manuals, scanned by us and stolen (yes, stolen) everywhere else.
An invaluable source if you are into vintage B&O!
Jacques
I would say it was an inside job, I see the signature.
I do have a serious question, about capacitors, it is the change or not to change question. On the CD 50 I have that is working near perfect, I know the sound for me is not as good as the one where I changed the capacitors. So do I keep it in as near original condition as possible or do I change how it sounds?
PS Patents last 20 years I think, maybe all manufactures should be obliged to deposit their service manual on a secure interent site so we don't throw away fixable equipment. In this day and age when a manufacture like Mercedes and Apple make products more difficult to repair or unrepairable or obstruct we only have ourselves to blame.
The classic VW combi, a vehicle where you could have the engine out in 15 mins without rushing, look up the engine parts in a Haynes manual and have a whole rebuild done in a day. Mercedes Viano by comparison, we will send a truck to collect and will look at it in about two weeks.