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
Good evening forum!
I recently aquired a BG 4000 for very little money ! Planning to follow Menahem's repair & restoration project via his Website.
The BG is in remarkable external condition for 40 yrs old. I knew it had some mechanical issues.
Wood frame 9/10, Acryilc Cover 7/10, Alu 8/10, Platter 9/10, Base 10/10, Cables 10/10, MCC 20EN near perfect , just crudded-up with dust.
The BG powers up with a strong relais-click via ON button. Platter turns. Tracking-arm projects light and displays B&O Logo in red. Pressing the "west" Arrow-Button gets the Tone-arm moving toward center. The stroboscope seems to perform.
Now for the bad news: The tone-arm won't lower when the "South" arrow is pushed. The STOP button must be held patiently down while the Pick-up travels slowly to the right. BG only switches -off when arm is parked on the extreme right. The "East" button has same effect as stop button (Arm travels right and parks) The 33/45 Red bulbs don`t Illuminate - ever. The Scale & Cursor don't illuminate. The 33/45 Alu-Rocker-Switch seems to be stuck in 33rpm. mode and has seemingly no function when either speeds are selected. None of the automated play functions work as described in the Manual.
I have dismantled the Alu-covers according to Service-Manual, and checked for visual anomalies on the mechanism and PCBs under the Controls. The general internal condition is very original. I think this BG was very seldom worked-on. Screw-heads are neat. Sealing-Wax is still in-place. The copper-Springs holding the Alu-Controls sit nicely, and hold the Alu-plates in-check. When pressing the various functions, one hears a faint Click as the contacts meet.
I have carefully oiled (Sewing-machine oil ! ) all the pivots, solenoid, copper damper etc just as suggested by Menahem. To no avail !
I really don't want to junk this unit, so I'm hoping that someone on the forum with the know-how can post some hints on where to start and which components may be culprits. I'm really hoping too that Menahem could pick his brains, as I'm sure he's been thru this more than once. I have good tools, solder-station, magnifying equipment ( and some patience left). I just don't want to meddle-around, trial & error, and do more harm than good, or roast the unit.
Thanks for reading and for any considerations
Cheers
Zorb.
Good evening community !
could one of the BG 4000 Aficionados please describe where the infamous Reed-Relay is to be found. ( Board No. & location No.)
The one responsible for speed problems, and mentioned on P.1 of the Troubleshooting schematic in the SM. I've found 2 references to Reed's on PCB 2 ?? but I'm not sure if these are to-do-with 33/45 switching.
I still have no automation whatsoever on this deck.
Frustrated !!
Thanks in advance
Might I suggest, without being disrespectful, that if you can't find the speed change relay then this is not a project for you. This machine really is quite complicated, using DTL i.c.'s which are very hard to come by and a fair amount of experience is required when fault finding.
For your information the reed relays are on the power board but the speed change relay (not a reed!) is on the main control board. If there is no speed selection you may have a problem on the logic board, which is under the keypad.
Olly
Many thanks for reading my post Olly !
I'm grateful of your warning also !
I got into B&O earlier this year, hobbywise. With Martin's (Dillen) advice & parts, I managed to get my BC 9500 & BC 9000 back into service. Usual Cassette & CD problems, capacitors, belts etc.
I bought the BG4000 fully expecting a challenge but not realising quite how compact and finely balanced everything is. I felt that there were enough troubleshooting posts and pics to help me along.
I could probably put the deck into a service-center and have it fixed-up, but that was'nt the reason i bought it ! I enjoy tinkering with these things and connecting (via Forum) with other like-minded-souls.
Anyways, many thanks for your pointers !
BTW, in the troubleshooting "map" there is a box -question:
"does reed-relay function, Dial illuminated ?" after turntable power has been established and in direct connection with loss of 33rpm speed-change.
I don't know now how reliable the troublshooter is, after your comment ?
Many thanks & good luck with your projects.
Zorb
Munich
Hi Zorb
I saw your post only now! If you haven't junked or sold it, here are a few points.
Firstly, while it's nice that there are lots of pretty bright lights on the keyboard, they are not critical to circuit functioning, so don't worry if they do not illuminate - yet!
You have no option but to get in and clean the keyboard contacts. Those are critical to proper function.
There are 8. Desolder and remove only the "bridges" for cleaning the little "nipple" underneath.
Do NOT remove or bend the flat strip "plungers" - I can tell you from experience, that if you remove them, you may very likely never get them aligned again, rendering the keyboard useless.
Using proper contact cleaner, remove all the old oxidized crap from the plungers, and from the underside of the bridges.
On the \/ , < and > contacts, there is an extra little pin under the plunger, which must be clean, as it is permanently closed. Wet a small rectangular cloth, and gently slide it side to side between the pin and plunger, to clean that contact area.
After that is all done, check with an ohmmeter for proper function of all the contacts.
Until everything is functioning perfectly here, there's no point in continuing.
Menahem
Hello Menahim,
I am a new guest on beoworld and reacting on your post above, maybe you ca help me out to solve some problems I have with my Beogram 4000.
I own it almost 2 years and it was in good working condition a year ago . I did not use it for a while, a week ago I decided to use it as my main turntable. I start it up push the start button nothing happened. after a few seconds it went off. Tryed again, the same . Opened the deck checked for damage loosen wires etc. putting a new small belt on the slide driveshaft an push the start button again, nothing, same as before, then pushing the start and the left arrow the slide and the arms running back and forwards when I keep pushing the left arrow button the soon as I free the button it runs automatically back and the power gets off. When it’s on and running like described above and push the off button nothing, the up and lowering button for the arm is also not responding. the arm goes up and down when I push the piston handle by hand. The spindle also makes a sound as a car wheel without a bearing. This I suppose is a easy to solve mechanical problem – the start problem could be a electric or keyboard contacts. hope you can give me advice etc. to get this beautifull turntable running smooth again.
sa your explanantion / you mentioned 8 contacts / saying desolder / cleaning etc. But! how to desolder , looking at it and saw 8 plastic boxes wth plungers / how to check them for proper function.
It's a delicate job / maybe its a better idea to clean the cobtacts carefully with a fiber glassrod what do you suggest ?
greetings, Barn
Barn
Do NOT remove or unsolder anything on that PCB. ABSOLUTELY NOT!
Look at my picture of the PCB immediately before your message.
You need a can of Contact Cleaner Spray, and some small rectangular strips of card (like a plain white Business Card), which you soak with the contact cleaner, and then you slide them in and out at the flat plunger strips, in order to clean the contacts.
To repair the solenoid piston to working condition, you must disassemble the complete mechanism, remove all the old grease completely, put on new Motor Oil (never WD40), and then reassemble.
Remove the spindle - clean out the old grease, and squirt in new Motor Oil.
Menahem, THX for the fast reply and info, I start to clean, it was realy neccesary, the contacts looked fet and black , manage to clean all went wel but I think I found the troublemaker. it was the last I had to clean . putiing away a bundel of cables and underneath I saw this ( picture) missing a bridge ! suppose there should be one / so no what ? I realy don't know how this bridges are fixed to the board. soldered? and how to get one . will try at the local electric suply store, they are specialized in all kind of electric spare parts relais etc. even ftom the 50ties / hopefully they can help/ or do you have any sugestion / I spent an hour to surch into the deck and around the workspace because it coild be possible that he small piece was fallen out during dismanteling . no luck
Menahem. sorry to bother you with such silly questions , I had to look better, start to investigate the board beneath te strip and saw there was a contactpoint underneath . worry for nothing / I cleaned the plunger already and it works fine / anyway; how about the solenoid / I thought there is no reason to oil t the piston / or am I wrong?/ because its a electric magnetcoil / dissambling the mechanism cleaned and fresh oil / so far so good.
You've done a beautiful job in cleaning the contacts!
To prevent future oxidation, spray on Contact Cleaner now, but do NOT wipe it off.
I understand that everything is working fine now, is that correct?
If you need new belts, contact Dillen (Martin Olsen).
OK! good tip, I wiil do.
the deck is not working at the moment I have to reassemble and fix the board / panel etc.
but what about solenoid / just cleaning the mechanism / and not ( oil) the piston in the solenoid ?
I will inform you when I start up the deck again / hope it works.
THX !
Dear Menahem,
Putting everything together / pushing the start button, stroboscope light went on. and after 5 sec the unit goes of / pushing again start/ same / push start and immidiatly the left arrrow . slowli the slide start to run a bit and went automaticly back .
verry frustrating / don't know what is the problem? maybe the contacts of the in the panel / which I cleaned / or bad wipers contacts ?
In some cases when I push start the solenoid reacts for a second immidiatly / toke off the buton plates and push the little pin (left arrow) and the carriage runs over the spindle to the end as long as I keep my finger on the button. the pickup arms are not mobing at all when I start.
I am desparated / Whats wrong? / don't know how to test further to find the problem and of course a solution.
in the service manual is now explanation of the functions of the contacts and how to adjust them etc,as soon as I put the paltes back troubles become more complicated.
HELP!
I would recommend a complete replacement of all electrolytic capacitors and the motor-drive transistors, which are bad at this point.
Menahem, sounds bad, I searchd the service manual can't find it / were are they loxared and which one / capacitors and motortransistors / how to check them good or bad / is this complicated/ is this a specialist job. or just solder work and replacement / when it's to complicated I wil sell the Beo as it is and look for a less complicated recorplayer / Garrard / Linn/ Lenco and Thorens.
Which country do you live in?
The Netherlands
There is no point in looking for another Turntable - they will all require repair, no matter what.
The BG4000 is the best of the best.