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
Søren,
Cleaning the big trimmers? My God, it sounds like my Beomaster 4400, only you HAVE to make the best of yours and my idiot [blank] didn’t.
Magnificent work. I can’t wait to hear how your BL 5000 sounds after all your efforts are completed.
And Søren, I assure you, I am not the only one that is so mightily impressed! We all are.
Jeff
Beogram 4000, Beogram 4002, Beogram 4004, Beogram 8000, Beogram 8002, Beogram 1602. Beogram 4500 CD player, B&O CDX player, Beocord 4500, Beocord 5000 T4716, Beocord 5000 T4716, Beocord 5000 T4716, Beocord 8004, Beocord 9000, Beomaster 1000, Beomaster 1600, Beomaster 2400.2, Beomaster 2400.2, Beomaster 4400, Beomaster 4500, Beolab 5000, Beomaster 5000, BeoCenter 9000. BeoSound Century, S-45.2, S-45.2, S-75, S-75, M-75, M-100, MC 120.2 speakers; B&O Illuminated Sign (with crown & red logo). B&O grey & black Illuminated Sign, B&O black Plexiglas dealer sign, B&O ash tray, B&O (Orrefors) dealer award vase, B&O Beotime Clock. Navy blue B&O baseball cap, B&O T-shirt X2, B&O black ball point pen, B&O Retail Management Binder
Started to assemble
Output and power transistors mounted properly on the cooling element
Collecting Vintage B&O is not a hobby, its a lifestyle.
Yesterday I continued assembling, Placed and glued the fiber disc for the TR leads
Here a closer look, as you see the plastic cover on the nut is broken, I glued it with crazy glue. Didnt find a good replacement over here
I then went on and attached the small PCBs with the TRs with a lot of heat paste on the cooling element
Closer look
Soldered all the output TRs
And here how far I got yesterday
Went on today (getting excited) but found out that yesterday I forgot to attach the power supply cable, so I had to take the transformer out again.
Here the transformer in again, and speaker outlet assembly, switch assembly, fuse board and big caps also in and soldered with all connections
I found some rubber that I cut to size to be able to use the original cap holders, these caps was the biggest diameter caps I could find without having to pay a fortune for them
The lower PCB got attached, and all connections to the upright standing PCB and the right hand switch assembly soldered, and thats where I got to today, tomorrow onto the front of the chassis and the missing PCB
Hi Søren,
Most impressive, as always. Brilliant workmanship.
¡Salute!
Well done Søren. I haven't had much time to follow Beoworld lately - but I follow your thread with interest.
One of those Things I like about Beoworld is these threads about restoring old equipment. This old stuff is definitely worth keeping, in a time when lots of people buy new phones every year - and new flatscreens every second year - and listen to music through some cheap Wireless all-in-one speakers.
Guess I'll now have a Tequila in my BeoBar, and send my best wishes to you in Mexico 🍹
Nothing short of amazing!
Much more rewarding than what I am doing at the moment - fixing bloody computers...
Jacques
Nice work and great pictures as usual. An all-out job with desoldered wiring looms is a sign of formidable dedication
A piece of general advice though:
Søren Mexico:I then went on and attached the small PCBs with the TRs with a lot of heat paste on the cooling element
Avoid using a lot of heat paste. It is not that great a thermal conductor after all, its purpose is to displace air from the pores of the metal and to fill air pockets. Best cooling will still happen with a metal-to-metal contact where ever possible, not through a thick mattress of heat paste.
But the cooling surfaces in old products like this may not be very even (thus they'll need more paste) and they also aren't nearly as critical with cooling as modern high performance microprocessors, for example. I don't see excessive usage so I'm sure your Beolab will be fine. And I should really start with mine - this will a be very helpful thread when I finally do!
--mika
This BL was so dirty that getting all the components out was the only way to clean everything, comes to it the corrosion damages on the transformer side and the damages from leaking caps on all 3 PCB, assembling I still find dirt in places and have to clean again and again,
Desoldering all the wires is easy, taking pics and then editing the pics with wire markings takes more time than desoldering, A good digital camera with macro function is a must,
If any of you start out doing yours make sure you get the horizontal mounted axial caps the right size or at least same diameter, the 220 uF I got from Martin are too thick and yesterday i had to desolder one to get at the solder peg for one of the wires, in other places I had to mount these caps "in the air" not to have contact with nearby components, If you have to change transistors (black drop Fairchilds) make sure you get low noise TRs, Frede pointed that out for me. I will use low noise TRs in the sound pad in my next objects where possible.
Here a pic from my wire marking
I for one will use radial caps to replace upright axials. In old equipment when radial caps didn't exist it made sense to use those to save space but now I find it hard to justify the use of axials in this position, and in addition to that most quality electrolytics are radial, period.
After some time to do my normal work, to be able to pay for this hobby, 2 weekends where I had to be nice to the family, today I finally got a couple of hours to do important work
Front chassis part in and the switch assemblies aligned, will probably have to align these again when Fredes beautiful fronts are fitted
The 2 lamps renewed, and then I attached the volume and balance sliders, soldered all wires and did the "pull hard and hope they dont come loose test" on all of them, thanks to my pics it was an easy job to place the wires in the right locations.
Today I went on and attached the bass and treble slider
And could then get the last PCB in and solder all the wires in place
Here a closer look
Slowly it all comes together
Getting nearer to the first test I start getting a little nervous, next on is a final control of all connections where possible
Courage my friend, you have it all under control…. and you know it.
I can not begin to tell you how much I admire you and your intense workmanship.
Trust me on this; it will pay off….. and we ALL know that it will.
Not sure? Just ask the real mavens Frede, Martin, Jacques and they will tell you that you on the verge of complete success.
In your honour I was thinking of a cuba…… but in the end decided on toasting you with a glass of inexpensive (all I can afford) British Columbia white wine. Salute!
Yesterday I had time on hand, but I found some small failures in the house, a leaking water valve, some trees needed pruning, checking oil and levels on the car and cleaning a little here and there. In other words, I chickened out, that blasted BL 5000 amp was laughing at me each time I passed it. I was standing in front of it, just starring at it a couple of times, but the chicken won each time.
Today I told myself, dont think about this as the holy grail, you have done several other units, which you just connected and tested after assembling, some with failures others not. So onto it.
I must remind you of Johannes Gutenberg´s, (to whom I owe my education and 45 years of hard work), words after he printed the first pages of Gutenberg´s Bible, "And There Was Light" (Es Warde Licht) He must have felt the same as I did today.
I checked everything I could before I connected the BL 5000 to my Variac, connected my DMM to the DB test point, then with the Variac at "0" turned on the BL, went slowly up with the Variac, when the DMM showed about 30 V the power on lamp started glowing a little, I continued increasing the voltage to 110V AC, cheking the DMM all of the time, at 110V AC it showed 57V DC, I adjusted with the trimmer 457 to 60V DC, turned off the BL and then chanced the Voltage selector to 130V AC, turned on the BL again turned the Variac to the end, it showed 125V AC, the DMM showed 59V DC, I adjusted again to 60V DC and left it on for about 10 min. It stayed stable at 60V DC, I then checked the 33V DC at testpoint DP. it was stable at 32.8V DC. Again I let it stay on for about 10 min. it stayed stable.
Here the DMM
Next on is to adjust the idle current, normally I should desolder the 460 and 469 resistors and connect my DMM in series and then adjust to 25 mA left and right channel.
Question: Anyone who can tell me the Idle voltage (measured over resistors 460 and 469 ??), I dont like to desolder and then solder again.
After adjusting the idle current I will have to adjust the symmetry at the emitter of TR 410 and TR 399 to 4.2V DC with a 4 Ohm speaker load, the only speakers I have that comes near is 5 Ohms measured at the speaker plug, will these do. or can I insert a resistor instead ??
Søren Mexico: Question: Anyone who can tell me the Idle voltage (measured over resistors 460 and 469 ??), I dont like to desolder and then solder again. After adjusting the idle current I will have to adjust the symmetry at the emitter of TR 410 and TR 399 to 4.2V DC with a 4 Ohm speaker load, the only speakers I have that comes near is 5 Ohms measured at the speaker plug, will these do. or can I insert a resistor instead ??
Use Ohms law. U=RxIIn your case R=0.22 and I=0.25 so U=0.0055 (put it at 6mV) measured across one resistor.
5 ohm speakers will be fine.
Martin
Dillen:Use Ohms law. U=RxIIn your case R=0.22 and I=0.25 so U=0.0055 (put it at 6mV) measured across one resistor.
Thank you Martin, clear and simple, a 5 year old could have figured that out, but not me, just because I´m too lazy to desolder and resolder I have to show how my brain functions are leaving me. I solve a lot of mechanical problems calculating, and of course this goes even more for electronics, next time I will think before I ask
Forget the chicken feelings. You handled your Beomaster 4400 fine so you can master this one as well. Keep on keepin' on.
John
I went on to adjust the idle current, right channel no problems but left channel showed 60 mV could adjust it down to around 18 mV with the trimmer to max.
Checked all connections (wires) checked diodes left channel, checked all new caps for polarity, checked TRs (Ohms) left channel same measurements as right channel. Checked all voltages according to schematics, only differences was + 0.2 to 0.3 V all over.
Voltages checked in red circles, right channel shows 6 mV, left channel 23 mV, need help or good advises
Please check above, help needed
Thank you for all the help and good advises, I'm stuck here, I have been searching for failures now 6=7 hours, I'm not giving up but may have to pack it away for a while.
I have kept quiet, not from any lack of interest, but rather because I have no help to offer. (I wish I did.)
Maybe it is high time for a cuba after 6-7 hours of painstaking and frustrating work. Or how about a pitcher of white Sangria? Yes, yes I know, the red is more expected, but the white is so festive. Just a thought.
Salute!
Thanks Jeff, I will stay with my cubas, that frigging apperatus is still swirling around in my head, I put on a brainless series on netflix, just to see something you dont have to think about
It looks as if something was injected at the input of the amplifier. Have you monitored the signal, or plugged a speaker?
chartz: It looks as if something was injected at the input of the amplifier. Have you monitored the signal, or plugged a speaker?
Thanks Jacques, will jump onto that tomorrow, as always I´m starring me blind on one part.
I was thinking of hum, perhaps.
chartz: I was thinking of hum, perhaps.
Yes it could be, but wouldnt I get elevated voltages in the end amp there is no differences according to schematics, no differences right to left, only the difference in the idle current. I will go looking in the preamps
With all voltages fairly correct, I think we can rule out a defective semiconductor.
Check the resistors related to the idle current trimmer. 330 and 470 ohms respectively in the schematics but maybe different on the PCB.If f.e. the 330 ohm resistor has gone high, the idling regulator transistor won't close enough to set the idle current right.
Will try first thing tomorrow, thanks
- Or the HFE of the idle current transistor is too low.
As of 17:55 o'clock Wednesday October 4, 2015, I 'm listening to music through a BL 5000 classic amplifier, using my Beovox 3702 for test.
First song was of course Suzi Quatro, I walk through the fire with you. This because this beautiful BL 5000 did just that and will do in the future, well there was no real fire, just in my soul to get it working,
The problem was dead 470 Ohm resistor, (open circuit) and the stupidity of the restorer. I inverted the emitter and the collector of the BC115 idle current transistor, i found it, Martin and Jacques brought me on track, THANK YOU guys.
I am monitoring the idle current as it plays, all sliders work without noise, high/low filter work, loudness work. the tape selector gives some noise when turning on and off, but I think working the switch will take care of that, probably there will more of this on other switches, there are no audible "extra" noises, not even when pausing the music (from computer) and turning up to full volume. I'm happy. More to come
Great news! Way to hang in there. John
Triumph!….. we are all celebrating vicariously with you…. and because of you and your “never give up” tenacious attitude.
Plus isn’t it fantastic to have friends like Jacques, Martin, and Frede helping you? Well of course it is. (If I left anyone out, it was unintentional.)
Bravo the team effort….. starting with Søren!
Getting there, running music from computer, through BL 5000 to Beovox 3702, now 2 hours playing without problems, will let it play for at least 2 hours more, until now nothing bad except for scratchy tape switch.
A beauty
Sure, now! After all that HARD work….. a beauty it is!
Well done!
How's the labour hour calculations going?.... :-)
Dillen: Well done! How's the labour hour calculations going?.... :-) Martin
If you include the well earned Cubas and Tequila I dread to think!
Seriously well done on yet another great and meticulous job. Frede will be proud of your efforts/achievement. How do you think it sounds then? How does it compare with some of your other receivers?
Dave.
I'd love to to hear it! I'm always impressed by your work!
//Bo.A long list...