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
Sooooooo I finally got myself a Beolab 5000 , and it is perfect visual shape, yeeeahBegun renovation, could see that atleast half of the caps were bulging, so I took the decision of total recap, to begin with.Endless work...sooooo many caps in it.Have decided to order new windows from Dillen, to start with.Anyone that have tips for this renovation ?
My re-capped M75 are my precious diamonds.
Check my thread, dont forget to change the black drop TRs ( there are 2 black drops in the cooling elements, open the slide poties for cleaning-
And if you have a good idea on how to clean the switches please tell, the switches are the biggest PIB in this amp.
Shortly Sonavor will start on a BL 5000 so stay tuned
Collecting Vintage B&O is not a hobby, its a lifestyle.
Thanks Sørenintersting, why opening the plasticcpas over the output 2N3055 ?Why is cleaning there important ?
Wrong written from me, there are 2 BLACK DROP TRs in the cooling elements, they need changing.
Open up the slide potentiometers for cleaning.
Dont understand what you mean by black drop
these guys ??
here
This is from a Beomaster 5000 (not a Beolab) but here is another photo of the "black drop" transistors Søren is referring to.
About the switches, well not all of them seem affected. I've got one of the last produced and the switches are fine. So are the caps by the way.
Jacques
Jacques, what is the serial number and series on yours?
John
Beolab 5000 type 5303, serie 08, serial number 46619.
What about yours Christian? What is the type, series and serial number?The one Søren just restored was a type 5305, series 80, sn88262. One of the latest Beolabs according to Frede. It would be interesting to compare the differences. Is there a way to tell from the numbers what year is was made?John
5303 no 65500
I see some changed caps in the pic, did you change them Christian or did it come that way
Image was half way through recapp.I have used my choices of caps. not axiell caps but radiels because thats what I had at home.The 470 uF have I increased to 1000 uF as they are pure smoothings.The only reason they were choosen 470 at the time was limitation of size.There are a few caps here and there that I have increased value due to electronic design.
And have made my decision not to do as deep renovations you did Sören.my BL5000 is in excellent shape.I am awaiting some more caps and after that I will slow start it with 30% on the variac and measure idle current. If that goes well it is readyI am not so sure that transistors needs to be replaced, if they work the work.IIf I take decision to replace the 6002 I will use equalient BC549 and 559 as they are low noise transistors.I have checked out the spec and they should go well
In after thought I would go for radials caps instead of the standing axials easier to get equivalent sizes, as for the black drop TRs Frede recommended me to change them with BC 550/560C but BC549/559 are indeed very close. Frede has found out that these TRs gives intermittent failures (distortion) at times.
Compared to mine yours look very clean, how are the fronts ?
Christian Christensen: The 470 uF have I increased to 1000 uF as they are pure smoothings.The only reason they were choosen 470 at the time was limitation of size.
The 470 uF have I increased to 1000 uF as they are pure smoothings.The only reason they were choosen 470 at the time was limitation of size.
May I ask, on what do you base that statement?
And you are not using WD40 anywhere in a B&O - are you ?
Martin
Yes you may dear Dillen.It is obvious that it is very tight in the Beloab. I cant see how a 1000 uF would fit inside there.Even though the stabilizing circuits , dont you think they would have crammed in a 1000 uF if it would be possible ? WD 40 ? ohh no, The reason it is on my kitcchen table is that before I got to the BL5000 I was dealing with a tricky mechanical problem inside of a Pioneer turntable from the 70ths ;) Christian
Christian Christensen: Yes you may dear Dillen.It is obvious that it is very tight in the Beloab. I cant see how a 1000 uF would fit inside there.
Yes you may dear Dillen.It is obvious that it is very tight in the Beloab. I cant see how a 1000 uF would fit inside there.
So if you stick to that theory and method of restoration, you will "upgrade" all caps to the maximum possible value you canphysically fit, safely assuming that's what B&O did?
The engineers at B&O wouldn't design something to work best with 1000uF and then accept to only fit400uF because "There wasn't room for more".Not anywhere. - Let alone in a top-range amplifier like this.
WD40 not in a B&O but in a Pioneer, that makes sense...
:-)
The original 400uF was already well dimensioned - as the far majority of components in there are.That's also why these beasts work well and live long.It's your restoration and you can mount what makes you feel happy, but don't blindly up capacitor values in thename of improvement and do keep in mind, that something happens to f.e. the rush-in current when you up thefilter capacitor (- and particularly if you fit a low-ESR type capacitor, which seems to be an often misunderstood method of "upgrading").The increased load and stress on the rectifier diodes, the voltage regulators and the surge-limiting resistors mayor may not result in problems sooner or later. I recommend you don't just up capacitors without a good reason.Martin
- And if you replace the rectifier diodes with Schottky types, I will be writing again! :-)Martin
Not that I had any idea of replacing the rectifier....Hmm is is selen recitifer in it ?
Ahhhh now I understand what you were trying to say ;), got confused for a bit. :)
This thread will go in pause for a week or two.Have so many other units for other people that come in for repair.It started with showing my own B&O repair/refurb on a vintage hifi forum.Since I started this hobby 3 years ago I have had about 20-30 repairs of other brands. :)Nikko, Sansui, Technics, Tandberg aso. I have very little time for my own beloved B&O stuff nowdays....