Beogram 4000 malfunction after shipment

66 replies
T4
Offline
T4000
Bronze
Posted November 20, 2020 at 18:02 GMT
#2212393

Hi!

I have a Beogram 4000 that was damaged in shipment. It was well maintained prior shipment. I initially posted here: link, but got recommended by sonavor to start a thread here instead.
The [numbers] refers to the Service manual. More pictures and clips can be added upon request.

Mechanical issues found (but now corrected):

a)       The Slide was loose and tilted and the Detection arm was relocated towards the Tone arm (see picture IMG_3629.JPG). 

b)      Pulley [124] came loose during transport and has likely been rattling around freely inside the Beogram. (in this Beogram replaced by a metal version, see picture IMG_3630.JPG). It was found again under the Turntable [4]. The loose Pulley resulted in the free moving Slide.

c)       The Slide threaded rod (Spindle [224]) was hanging loose-ish, also an effect of the loose Pulley.

d)      One of the Slide Contact pins and its plastic holder (Switch E, SO - Switch off/Home position) were knocked off.

Functional issues found (please note that issue #5 is now permanent and overrules the other 4 issues):

1.       Tone arm lowering even if no record is present. Intermittent problem. Happened both on 7" and 12" position. The detector arm bulb is lit up, but something is wrong in the sensor circuits.

2.       Another intermittent problem: sometimes the detection arm function works when scanning an empty platter, but then when the Slide are reaching end position, the servo motor continues to push the Slide to the center. OFF has to be pressed to return.

3.       The Slide stopped over the 12" position, then slowly moving towards the center, then returning back home. This occurred both with and without record. Don't know if this is a normal operation, but it happens intermittently.

4.       When playing a record, the arm lowers, but after 1s the servomotor starts and the arm moves across the record for about 0.5-1cm (my poor Pink Floyd album).

5.       After that I started (in pure frustration) to adjust mechanical bits and pieces according to the service manual. When I came to the step of Tracking force adjustment, I started ON, then pressed Reverse (>) to move the tone arm away from the platter. When I did this, the Slide decided to return to home position. I pressed ON again to repeat the procedure, but the Slide moved ~1 cm, then returning home again (see

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sonavor (archived2)
Bronze
Posted November 21, 2020 at 03:44 GMT
#2212394

Hi T4000

Okay, let's start.

The first step is to disassemble the Beogram to where you can easily observe the tangential arm assembly working.
Also to get cosmetic pieces out of the way so they won't get in the way and won't accidentally get damaged.

Remove the Beogram 4000 dust cover and store it out of the way somewhere safe.
Remove the deck panels and store them away as well. Be careful of the red, plastic indicator piece that moves with the tangential arm assembly to show where on the platter the stylus is pointing. That piece can easily get in the way and accidentally broken. So you need to protect against that.

For now you can also remove the platter and belt and put them out of the way.

This should now give you access and full view of what goes on with the tangential arm assembly.
Post some photos of those areas so we can identify things that are missing and things out of place.

A good start I think.

-sonavor

T4
Offline
T4000
Bronze
Posted November 21, 2020 at 11:56 GMT
#2212395

Hi sonavor!

Here we go, se pics below.

Here is also a new try to include the zipped video clip: https://archivedforum2.beoworld.org/cfs-file.ashx/__key/CommunityServer.Components.UserFiles/00.00.03.05.15.Beogram+4000/IMG_5F00_E3679.zip

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sonavor (archived2)
Bronze
Posted November 22, 2020 at 00:51 GMT
#2212396

Great photos. Just the right size to still view the detail.

From the photos your mechanical parts look like everything is positioned and aligned correctly.

I believe you said that the fixed arm had come loose during shipping so you had to fix that.
There isn't too much adjustment in mounting the fixed arm but there is some.
The Beogram 4002 manuals say that the fixed arm should be perpendicular to the rear rail that the tangential arm assembly travels on.

Check if that is so. It looks good in the photo. The tonearm also looks nice and parallel to the fixed arm so that looks really good too.

In your initial photos of the Beogram 4000 it looked like the tonearm was not in parallel when it was lowered.

You can check that by pressing here (in the photo below) and observing how the tonearm lowers.

Pressing in on this point simulates the lowering solenoid operation.  You should see the arm lower straight down.  Releasing the lever should result in the arm raising straight up. If that is what you see then that part is good.

The connecting bar outlined in green dots here positions the tonearm in reference to the fixed arm.
The resting spot for the tonearm is where the point of the lifting arm rests in the "V" of the connecting bar.


The two screws outlined in green dots allow that bar to be adjusted slightly to set the tonearm parallel and the "V" channel lined up with the lowering bar.

Again...you arm assembly looks good in your photos so hopefully everything will function good in the manual lowering and raising test.

If that is the case then we can move on to check the platter height to the fixed arm and some other arm position checks like the lowering limit of the tonearm and the tracking force calibration.

-sonavor

 

 

T4
Offline
T4000
Bronze
Posted November 22, 2020 at 13:56 GMT
#2212397

Hi sonavor,

To make it more easy to share the videos, I have now created a YouTube channel.

Error #5 as described in previous posts can be seen here: link

 

Check 1:

When I initially adjusted the detector arm, I made it perpendicular with the backside of the Beogram, not the rear rail. Now I realized that the whole dance proofing assembly can not only move, but actually stay in different positions (). With that new knowledge, I loosened the 2 screws again and readjusted the detection arm from good to very good, now perpendicular with the rear rail. The 2 arms are now completely aligned, with 8.5mm in between (0.334645669 inches).  

 

Check 2:

When lowering the tone arm, it looked like it makes a little move to towards the detection arm, just before it reaches its lowest position. I made some adjustments according to your excellent guide.

Lowering the tone arm (before adjustment) - Top view: link

Lowering the tone arm (before adjustment) - Side view: link

link

Lowering the tone arm (after adjustment) - Top view: link

Lowering the tone arm (after adjustment) - Side view: link

 

A briefly mentioned in my first post, I initially adjusted the following according to the Service manual and/or Beolover's instruction videos:

  • "Lowering (Depth) Adjustment" according to section 4-5 in the Service manual
  • Tracking force adjustment (
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sonavor (archived2)
Bronze
Posted November 22, 2020 at 20:08 GMT
#2212398

Hi Per,

The lowering doesn't look too bad as an early adjustment. It will need to be rechecked later.
It kind of looks like some of the lateral movement you are seeing is from the floating chassis. I typically do those initial adjustments with the floating chassis and tonearm assembly completely removed but I would not recommend that here. Especially because it appears that your Beogram 4000 is pretty close to being correct.

One thing you could do is tighten down the floating chassis as if for transport to it doesn't move while you are manually pushing on the arm lowering.

One other thing to note is the distance between the fixed arm and the tonearm. 
My Beogram 4000 manual does not state anywhere (that I can see) what that distance should be. 
In the later 4000 series (Beogram 4002 and 4004) their service manual states the distance between the arms as 7.7mm.
For now I would leave yours alone. The main thing right now is to get everything where it will function.

The next step I would make is checking and adjusting if necessary the platter height to the tonearm/fixed arm.
You can do that by putting the platter back in place but without attaching the belt. You don't want the motor turning the platter during these tests.

Did you say you did or do not have a service manual for the Beogram 4000 ?

I don't see one in the Beoworld service manual section. We need to get one added there.

I will post a picture of the platter height adjustment so you can check that.

Regarding the video where your Beogram 4000 tries to start, then immediately stops...we may have to look at what is causing the analog control logic to fail there.
Typically there is a poor connection somewhere and/or a problem with the button/actuator alignment. You posted a couple of photos of the buttons and actuators. The alignment of those is very critical to the Beogram 4000 operating correctly.

-sonavor

 

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Offline
sonavor (archived2)
Bronze
Posted November 22, 2020 at 20:42 GMT
#2212399

Hi Per,

One other thing regarding the Fixed Arm and Tonearm positions you currently have...
The arms looks close to where they need to be and they are parallel. 

Recheck the arm lowering with the metal covering for the Fixed Arm and Tonearm back on.
I am wondering if it will fit properly with the distance between the two arms you have it set to (8.5mm).
It may have problems with that in which case it will have to be re-adjusted.

-sonavor

T4
Offline
T4000
Bronze
Posted November 23, 2020 at 16:15 GMT
#2212400

Hi sonavor,

Regarding the distance between the fixed arm and the tonearm, I measured the drawings in the Service manual and each arm is as wide as the space between them. I then measured the actual arms. They are 8.25mm. So, the space between my tonearm and fixed arm is 0.25mm wider than on drawing (+/- deviation from me measuring a paper drawing with calipers). A video of the arm lowering when the metal cover is back on can be found here:

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sonavor (archived2)
Bronze
Posted November 23, 2020 at 16:59 GMT
#2212401

Hi Per,

I wouldn't trust making measurements off the service manual diagram. Unless the diagram specifies the distances any measurement would be an approximation. From your video it is difficult to tell how well it is operating. The cover appears to fit fine. It should easily slide on. The important thing is that none of the moving parts of the tonearm are touching the cover when the tonearm moves (vertically and horizontally). 

That is good that the platter adjustment is correct. So far it appears that the Beogram was set up correctly when it was shipped to you and your reassembly of the pieces that came loose are good.

For now continue to operate the Beogram with the fixed arm/tonearm cover removed...until you have the record play working.

I'm not sure I follow what you mean regarding the red, plastic slide connector pins.
Are you referring to the tonearm assembly position switches here (in your photos)? -

....and the metal bars that actuate them?


Those shouldn't require any lubrication.
The adjustment of those bars is critical though.
They have to engage the switch actuators just right so the switch engages but doesn't interfere with the arm assembly travel. 
If those are out of adjustment they require a lot of patience to set correctly. 
I would not try to adjust those yet. They should already be in the correct location.
You should check if any of the bars that actuate the switches are loose though. Everything should be tight in its place.

-sonavor

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chartz (archived2)
Bronze
Posted November 23, 2020 at 17:14 GMT
#2212402

Nice photos Per.

John you are the best. I wish I had some free time to help. I’ll be watching with great interest though 👍🏻

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