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Beogram 4000 parts and restoration

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Paul G
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Paul G Posted: Fri, Jan 29 2021 5:51 PM

Hello to all Beogram lovers.

I bought a Beogram 4000 around 1973/4 as part of my free form Hi fi system.  Brilliant deck.

Ran for some 15 years before updating to complete Beosystem 5000 with appropriate Beosystem speakers.

Beogram 4000 sat in my office unused but kept warm and comfortable could not throw out such a lovely piece of gear.  Then moved on to other B & O systems before retiring and downsizing to a Beosound 3200 system but of course no record deck.

Time has come to get the Beogram 4000 working again to play my large collection of vinyl.

So help may be needed.

Have read with interst all posts and blogs on Beoworld about Beogram 4000 refurbishments and am now about to put toe in water.

Firstly have taken deck apart and physically cleaned environment and asssesed condition. Does not look too bad for a 47 year old.  Cartridge is still intact and does look OK on careful examination.

Question 1)

First thing is I need new belts has anyone bought belts from:

Malvern Hills Audio in UK?

BeoParts in Denmark?

Is Martin Dillan still offering belts for sale?

I am then going to clean all contacts and relays before firing up the elderly beauty.

Question 2)

I have read about the need to replace some condensers. Should I do this before powering up the deck to see if there are other problems?  Which condensers need replacing?  Where can I get them? Radio Spares in UK?

I should now explain my skill level on electrical equipment is A level Physics, BBC technical training course in late 60's and some maintenance work on TV cameras in early 70's whilst a cameraman with ITN but then moved into production. So reading circuits is a dimm and distant memory.  Have rewired several houses, replaced PC boards in generator systems and even changed the battery and screen in an Iphone 6 but all by following instructions rather than intuition.  I've got the skill to change a condenser on a circuit board on the Beogram if told which one but not to measure the voltage across the motor terminals and diagnose the problem so will need help.

Thanks in anticipation I am looking forward to this adventure.

PS how can you get the pictures on the Post to fit within the text size, i have reduced down to 16cm wide, A4 size but still disappear off al edges?

 

 

 

 

Beobuddy
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Beobuddy replied on Fri, Jan 29 2021 7:29 PM

Tricky deck. A lot of points to look at.

For belts contact Dillen.

https://forum.beoworld.org/forums/t/45641.aspx

 

Craig
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Craig replied on Sat, Jan 30 2021 8:42 AM

It is a tricky deck....and a very complex one, it is however a very well designed and constructed deck which is why so many are still around and going strong. My inclination would be to have a look at the internal fuses and if ok power her up, its useful to know what was working before you start so you know if you have introduced any problems when "fixing" things.....the circuit diagrams are available on this site as are lots of threads of successful restorations for guidance......post pictures and ask questions here....we love it ;¬)

Craig

Paul G
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Paul G replied on Mon, Feb 1 2021 10:21 AM

Thanks Beobuddy.

I have tried to contact Dillen through the Beoworld site but keep getting my email rejected.  It is going to ***@***.*** but comes back with address unknown?

Do you have another email address for Martin?

Paul

Paul G
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Paul G replied on Mon, Feb 1 2021 10:28 AM

Craig,

Thanks for your help.

I have checked fuses, all OK.

Just cleaning all switch contacts some of which have shown some low voltage leakage in the "no contact" position and will then fire up system and follow flow chart check boxes.

Still wondering about replacing electrolytic condensers?

Can you help me on posting pictures.  I tried just pasting a .jpg into my comment and although it appeared to me locally it did not go up onto the site?

Thanks,

Paul

 

Dillen
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Dillen replied on Mon, Feb 1 2021 12:59 PM

I am right here

- and belts etc. are in the webshop:
www.beoparts-shop.com

Martin

Craig
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Craig replied on Mon, Feb 1 2021 2:49 PM

You will certainly need to replace all the capacitors, electrolytic and tantalum too......Dillen sells a kit with everything you will need, including a guide to help you achieve this.

Craig

Paul G
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Paul G replied on Mon, Feb 1 2021 4:09 PM

Hello Martin,

Thanks for your contact

I have found the shop and see the belts I need.  Craig tells me you also do a full set of Capacitors to change and update the system with installation instructions and a guide.  I can't see these in the shop under the Beogram 4000 parts, can you point me in the right direction?

If I get the belts and Capacitors in one parcel I can safe on post cocts.

I will also get my system fired up shortly after cleaning all the contact and slider switches and then see if i need any bulbs which I see you stock.

Many thanks,

Paul

Paul G
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Paul G replied on Mon, Feb 8 2021 11:58 AM

The Latest Progress with my Beogram 4000 restoration

I am waiting for belts and Condensers meanwhile I cleaned all the control switches and carriage switches following BeoLove's excellany videos.

Checking the connections after cleaning with a multimeter, all the connection switches for the carriage now appear to be working correctly (ie showing open or closed circuits when the appropriate carriage switches are engaged.  Similaril all the arrrow control switches are making contact and giving open circuit or closed circuit connections with the multimeter as appropriate when pressed.

So then i decided to fire everything up and see what happened.

With no record on the turntable:

I pressed ON, detector light on arm came on, platter spun, strobe light worked, I could select 33 or 45 speeds and the relevant speed light glowed.

The arm and carriage DID NOT track to the centre of the platter (arm did not move).. No voltage across motor OM2

I then experimented.

Pressing any arrow key and then the down arrow key caused the arm to lower and the arm then tracked very slowly to the centre of the turntable. (I have removed the cartridge and used a plasticine weight on top of the arm to replicate the balance position of the arm)  Once at the near centre of the turntable the arm raised and returned to its stop position at normal speed (as I remember it) turning everything OFF at the stop position.

The arm appears to be tracking slowly to the centre of the platter because its angle is slightly displaced inwards causing the tracking servo to power OM2.  By slightly altering the angle of the tone arm with a screwdriver I could get it to stop or slowly track backwards.

Experimenting further, as the arm moved slowly towards the centre of the turntable I stopped it by correcting the tracking angle and then played with the four arrow controls.

Up and down arrows raised and lowered tone arm correctly. RIGHT ARROW would raise tone arm which could then be moved at slow or fast speed back to the stop position where everything would turn off. (or lowered again and if arm displaced move slowly left or right).

LEFT ARROW would raise tone arm but it would not track left at any speed unless arm angle was displaced, so the left arrow button circuit appears not to be working.

Pressing the STOP button did nothing and arm did not raise.

I am now stuck and will have to go back and look at all restoration projects to try and find out what to do next..

Can anyone offer any suggestions or point me to a previous forum on this situation?

Thanks.

 

Paul G
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Paul G replied on Wed, Feb 10 2021 6:16 PM

Need some help here!

I am trying to follow the fault finding flow chart in the Service Manual for the Beogram 4000 - my arm does not track across the platter on switch on..

I have got to point where where question is "Q0 = low?"  Where do I measure QO?

(I know this text for Q0 are wrong but i can't find a way of putting a line above.)

Do I measure Q0 at the base of 3C13 to ground?  What voltage am I looking for? What is low and what is high?

Can i assume that anything near 6V is high and anything around 0V is low?

There are a lot of these high/low measurements to be checked but no clue in the service manual on the points to measure or what the voltages should be?.

Thanks.

sonavor
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sonavor replied on Wed, Feb 10 2021 7:22 PM

/Q0 is a derived signal from the Beogram 4000 control logic. The control system is analog but it does have some flip-flops built with NAND devices on the board under the operation button panel.

The logic board is extremely reliable and most of the time you will find that the source of various functional problems are with switches and/or connections.
On the Beogram 4000 it is very easy for the leaf switches to get bent and be a problem. That is why almost every Beogram 4000 restoration has a step where those switches are reworked.

Here is the control panel diagram

/Q0 is derived from 3IC0. 
As for the high and low voltage levels, I don't remember the full ranges but I measured 0.8V for a low and around 6V for a high the last time I worked on a Beogram 4000 logic board.

The problems you are having are more likely to be with the signals going into 3IC0 rather than /Q0 coming out of it.

-sonavor

 

 

Craig
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Craig replied on Thu, Feb 11 2021 3:35 PM

I love that breakdown of the logic board.....and I can confirm sonavors advice around the logic gates being very reliable, i fought one of these for weeks and was convinced i had a chip down somewhere.....turned out I had put silicone grease on the nipples that actuate the leaf spring switches when i restored them, the grease was making the  a nipple stick occasionally and causing the deck to switch to 45rpm on start up.....but only some of the time ;¬)

Craig 

Paul G
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Paul G replied on Thu, Feb 11 2021 6:00 PM

Thanks Sonovor and Craig,

The logic board breakdown is very clear and I am sure is going to be most useful

I have cleaned all the switches and contacts , that was the first thing i did.  All the switches seem to be showing correct values of OS or no resistance when I measure them and operate the controls or the carriage slide but cannot be sure of the connection path because i checked the switches at the actual soldered connections.  There may well be connection problems further down the PC track and that is why i was trying to go through the flow chart diagnosis to see where things go wrong. 

I have an Excel chart from a Forum with a list of Events and voltages but am slightly confused as to how to measure the voltages at the various points?

Where is the best place to pick to place the negative side of the meter?  Is there a clear earth point in the chassis or will any metal point do?

I am waiting to replace the Caps but keen to get some data before I do so to see what changes.

Paul

 

 

 

Paul G
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Paul G replied on Sun, Mar 21 2021 6:33 PM

Some time hs passed since I started the restoration of my Beogram 4000 originally purchsed in 1973/4.

This photograph shows the deck of the Type 5215 version which is in pretty good nick cosmetically with some operating problems i have mentioned above.

I decided to study all the Forums on previous restorations before starting anything.  There is a lot of very useful information on this site and i have already learnt a lot.  Its going to be a difficult restoration fo me because although mechanically adept I am not up in circuit repairs, its 50 years since I stopped doing any work in that area.

So thank you to Sonovor and Beolover for your excellant reports and step by step instructions.

First steps now completed were to clean all the switches both on the control panel and the arm transport slider.

This was all done with no power on the unit using the blogs supplied by Beolover on his website.  I used the very fine grade emery paper he recommended together with some WD 40 switch contact cleaner which i found to be better than Screwfix contact cleaner which seems to leave a slight residue.

I cleaned most of the switches in situ on the PCB boards having removed the top control panel as everything looked very straight and initial work with my multimeter showed resonable contact on most switches. After the cleaning the contact on all switches was nil resistance apaty from the 45 rpm speed change switch which had a very large gap to make the switch point and was not operating very well through then control panel.  I took this switch apart and slightlybent the top of the copper housing down so that there was less of a gap between the leaf switch and the contact.  I think some maintenance work had been done on the switches in the past and the components of this switch were slightly out of true when resoldered. On the multimeter all switches are now working correctly and continued to do so after the control panel was put back together.

th slider switches also are showing very low resistance on "make" amd OS when they are open.  The ES switch and SO switches are working under power but i have not tested the other switches with the turntable platter in place.  There are start problems when the ON button is pushed but i don't think this is connected to the switches now.

My next job will be to change over the scale illumination lights on the arm movement to LED's from Beolover. First I need to modify the circuit for the scale lights on PCB 3 which is currently set up with 2 x 24V bulbs working in Parallel.  One of these bulbs has gone anyway and they are not readily available.

 

Paul G
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Paul G replied on Tue, Mar 23 2021 10:45 AM

My Beogram 4000 Type 5215 has the 2 x 24V scale illumination lights in parallel on the PCB board numbered 8009015.  I wanted to change this to 12V lamps so as to use Beolovers 12V LED lights.

The original circuit board illustration that came with the 4000 in 1973 is shown below.

I disconnected one of the 100 ohm resistors and moved the post with the 24V supply (red wire) to the position it occupied at the end of the diagonal track to the RH light. The two bulb positions now become a series connection matching the polarity required by the LED boards from Beolover.

The PSB now looks like this with one track of the circuit disconnected (and erased on the illustration).

I then soldered the two small LED circuit boards in position and everything lit up correctly.

The next job is to change the power capacitors.

Paul G
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Paul G replied on Tue, Mar 23 2021 12:06 PM

My next job is to change all the capacitors in my 1973 Beogram 4000.  This seems to be recommended by the experienced restorers on the site and reading up on the subjject capacitors which are 50+ years old are always likely to fail at any time. However I am now entering my edge of experience. I started by replacing all the resevoir and motor capacitors because they are bigger, appeared easier to get at and Beolover does a full 6 (actually 7) capacitor replacement kit together with a 3D printed "holder" for the new capacitors.  There is alos a very good instruction blog on the Beolover website guiding you through the replacement of these capacitors (Thank you Rudy excellant information.)

Here is the selection of Capacitors I was setting out to replace.

I am posting my work on this restoration because i am much more of a novice than post of the contributors on the site and what I experience may help other novices to make the attempt to repair a classic piece of kit when it is virtually impossible to get this work done in the UK.  If there are people around who would do such restoration in the UK then do talk on the site.

Having carefully watched Belovers blogs and also followed Sonovar's Forum entry on this site I felt reasonably positive I could do this work. Looking very closely at the wirng involved made me realise it was intricate, a jumble of connected wires very close together in a tight space.

My first step was to make my own careful diagrams of all the connections, Beolovers is excellant but only by looking at all the connections and checking the wiring colours was I sure that I could put it back together in the right places (and if my soldering skills were up to it).

Just talking about soldering i have had a soldering iron (several) for years and done soldering jobs on cars, small radio repairs, resoldered control system wires on boilers etc etc. But I felt I needed better equipment and some practice on small electrical work.

I searched the web and watched a number of training videos on electrical soldering and gradually accumulated a set of tools and the right sort of solderin iron to buy.  I then set up a board and did some practical soldering on small components - getting better all the time.

My final step before starting on the Motor Capacitors was to make a complete list of every solder joint and wire to each capacitor, this became the tick list for work as it progressed.

This is the way i did the job, not the only way but logical to me and alos following some of Beolovers advice.

Label everything very carefully, there are some thick and thin red wires and bare wires round the Zener Diode and TR! which are easy to confuse once everything is unsoldered.

I started by replacing OC1 and OC2 which are relatively strightforward.  I removed the old capacitors first then sat the new Caps in place bending and marking the negative wires which are connected together.  Then took these out and soldered the negative ends as well as making short bent loops on the positive connecting wires for the yellow and blue wires to the power supply boards.  I tinned all the leads outside the cabinet making it easier to get a good solder joint when working in the more confined space. Finally soldered the two black wires together before soldering to the negative ends of OC1/OC2.

I continued with the main capacitors OC7, OC6, OC3, OC4 mounting them in the Beolover 3D printed holder, soldering connected wires, placing in position and marking lengths of wire then removing, tinning wire ends before placing in position and wiring.

I found it easier to remove the bare wire from TR1 and solder to Cap OC4 outside the box and the same with the Zenner Diode ZD24 and the thin red wire between OC3 +ve and the strap across TR1.

But this is a matter for choice and skill.  I found a 4 layer square of kitchen foil valuable for wrapping round wires close to soldering points and used a heat of 380 on soldering iron with quite a braod tip.

I used clip on copper and metal heat sinks to protect the component side of the wires I was soldering as I was concerned with overheating the components although the more skilful may not need to do this.

I found that where two or three wires were being soldered to the same place it was useful to bind them either with fuse wire on the bare wire end or a thin plastic strip on the plastic wire coating if there was more space and pre tin this group of wires before soldering in place.

A soldring stand with lazy arms and clips and large magnifying glass is essential as is a good adjustable light siource although twenty year olds will have less trouble than I did!!

It took time and I didn't rush but it all came together and when I powered up I have the same functions I did before the replacement of the capacitors so fsr so good.

Here'e a picture of the reworking, next time i think i could do even better.

 

 

 

 

Orava
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Orava replied on Tue, Mar 23 2021 6:04 PM

Hi

What did you use OC3 ? I have it marked 400μF.

 blah-blah and photographs as needed

Orava
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Orava replied on Tue, Mar 23 2021 6:04 PM

oh, double

 blah-blah and photographs as needed

Paul G
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Paul G replied on Tue, Mar 23 2021 8:29 PM

Orava, for OC3 I installed 3300 μF, it is down in my technical manual as 3000 μF at 50V

OC7 was 2 x 300 μF joined in series.

Beolover supplied the housing and the capacitors so they fitted the housing.

Orava
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Orava replied on Wed, Mar 24 2021 9:50 AM

Oh, sorry OC6 in BG4000 and 4000μF/25V according to manual. The one prior motor.

 blah-blah and photographs as needed

Orava
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Orava replied on Wed, Mar 24 2021 9:50 AM

Oh, sorry OC6 in BG4000 and 4000μF/25V according to manual. The one prior motor.

 blah-blah and photographs as needed

Paul G
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Paul G replied on Thu, Mar 25 2021 6:57 PM

I've just discovered an interesting wiring situation on the Beogram 4000 I am restoring.

The picture below shows the way the carriage motor is wired and I carefully marked this when I removed the motor wiring to clean the carriage switches.

 

I have some missing functions on the carriage drive and record detection but was leaving these until I have cleaned switches and replaced Caps and etc.

However I was looking at the wiring on the carriage drive and checking it with the service manual and discovered that my carriage motor drive is in theory connected the wrong way round.  The PCB diagram shows the wires from the Motor connected Red-White and Black to Grey.

I checked some photographs on Beolovers website and on Sonovars extensive restoration descriptions and both their motors were wired as shown in the Service Manual diagrams.

Thinking this could be a reason for some functions not working correctly I swopped the Motor wires over on my unit so that they matched the Service Manual.

On reconnection the mains and turning on I still had the same limited functions but the carriage and arm now moved in the wrong directions!! I guess the connections must be swopped at the motor end as well.  I did not bother to explore any further

I quickly swopped the motor wires back to the way they were (wrong wiring) but now the carriage and arm behave logically in the right directions although I am still missing some functions.

Has any on else come across this in a Beogram 4000?  My unit was serviced way back in the 1990's by a B & O dealer because the manual movement of the carriage in one direction had stopped working but there was no fault with the carriage drive motor so i would not have thought this was touched.

Very strange!!! Any thoughts???

 

Paul G
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Paul G replied on Fri, Mar 26 2021 6:02 PM

Can anyone identify this part?

I was removing PSB 2 to replace some capacitors and noticed the yellow sleeve covering this "fuse??" was very flexible. I removed the sleeve to discover the glass tube had broken and the item had split as shown.  It does not appear to be listed on the parts list for Board 2 but on the Circuit diagram there is a Fuse? marked "0,4a traeg" which connects to one of the secondry transformer windings? Does anyone know if this is a fuse what rating it is?

Any help appreciated.

 

 

 

Paul G
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Paul G replied on Thu, Apr 8 2021 5:44 PM

Discovered that this is a slow blow fuse "traeg" is Danish for slow so that all makes sense now.

Have replaced fuse and functionality is as before.

Paul G
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Paul G replied on Thu, Apr 8 2021 5:56 PM

HELP!

Help with defining potentiometers on PC board 1.for my restoration

I want to replace some of the "Trim Pots" on board 1 and have the ratings but on searching online was overawed by the range of possibilities.

Using my normal supplier in the UK "CPC" I searched for Single Turn, Top Adjust 50K potentiometer and got a range of 6 different components all slightly different.

Carbon Composite, Cernet Square and others all with variations.

Can someone give me the type I should be looking for?  I dont want to discover I have the wrong pin configuration or the wrong type.  Thanks

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