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
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Hi,
I recently decided to buy Beogram 8000. The one I bought supposed to be fully functional. Once I received it and powered it up its full functionality wasn’t really the case. Turntable sinned and that was pretty much it. Since I enjoy bringing old pieces of equipment back to life I took a challenge to get Beogram back to working state. So far I:
Still to do:
While working on this Beogram I had few questions that I hope you with your kindness, will be able to help answer:
1. turntable tacho Can you guys share your opinion about state of this tacho disk? It looks to me that some sort of coating starts to peel off from main tacho disk. I didn’t touch it. Is there something that can be done here to save it or this tacho disk needs to be change? Light seems to be going thru perforations reasonably OK and Beogram seems to hold its revs just fine
2. arm height adjustment Manual talks about 23mm clearance between top of the pickup arm and turntable surface.
I tried to measure this distance and I’m getting about 22.5mm. If I look at 0.5mm gap it is visible.
Should this height be adjusted exactly to 23mm? If so how this adjustment supposed to be done? Is there a need for some extra washers or inserts underneath of pickup arm mounting holes (screws B and C)? User guide does not explain this adjustment process (at least I don’t understand it).
3. slack on the arm mounting I noticed that slide chassis have a slack on the slide rods. I tried to capture it in this clip. https://www.dropbox.com/s/4ekufdem6bjgowo/slack.MOV?dl=0 Is this slack expected or there is something missing here?
4. pickup arm does not get back to the PAUSE position when I pause player at particular place in the records, wait until arms is parked back and then press PLAY arms back but not to the same place. It is offset by nearly 3 millimeters or so (to the canter of the record). It’s like position of analog movement is not preserved or something. Any idea where this problem is coming from (please note that I still have to change photo-resistors in manual so maybe offset is coming from there?)
5. red LED in detection arm what exactly is function of red diode mounted in the detection arm? What it supposed to indicate?
6. general operation This is just to ensure everything works as it supposed to. I tried to catch step movement of slide chassis motor and following-like analog response from pickup arm. https://www.dropbox.com/s/ruv6pocf9qx1xc4/arm_movement.MOV?dl=0 I guess this behavior is as expected, right? I can’t imagine smaller steps from servo motor when spindle with only 4 openings is used.
Thanks for your time and help guys.
Cheers,
Henryk
Hi Henryk,
The spindle nut repair looks pretty good. I repaired one like that in the past (only I used a nylon washer for the support piece). If it doesn't hold up Beolover can provide a new 3D printed replacement spindle nut.Regarding the tacho disk...The early series of the Beogram 8000 units had the plastic disk with a black decal. That decal eventually peels off as you are seeing. The later manufactured Beogram 8000 units and the 8002 units have a metal tacho disk. Martin (Dillen here on the forum) can usually supply new metal disks. I have used his replacement disk parts on several Beogram 8000 restorations and they work perfect.
The platter deck to fixed arm top distance should be 23mm. The adjustment for that is the third screw in that service manual picture you included. I guess it should be called "A"
The slack shown in your video is normal.
I would agree that the arm not returning to the correct position after a Pause is due to error in the pulse counting. That could indeed be a fault in the photo emitter and photo transistors of the tangential arm position sensor.
I have always been puzzled why B&O didn't continue from the Beogram 400x series and have the B&O logo on the end of the fixed arm. The plain red dot is too plain for this turntable. The only thing I see it do is pulse at a frequency based on how fast a scanning operation is being performed (<<, <, >, >>). I don't know how that is supposed to help the operator. Maybe I too am missing something regarding that indication.
The record play video you recorded looks normal. The adjustment is to be done with a particular B&O test record on a specified test track with the platter motor off. The tangential drive motor should advance after the initial arm drop down in 2 +-1 platter revolutions. Then every platter revolution after that. Since I have never found that B&O test record I use a couple of my own records that I experimented with and the always use those tracks. When playing records for real the advance frequency will vary a little per record. Especially if the record center hole isn't perfect (as many records aren't). The record in your video has quite a bit of back and forth movement probably because the hole is a little off center. The cantilever looks centered though so it looks to me like the Beogram is tracking it quite well.
From what you have shown I would definitely upgrade to one of Martin's metal tacho disks.
How is the arm lowering on that Beogram? Does in lower gently to the record or does it catch, then drop suddenly?
-sonavor
Hi Sonavor,
First of all many thanks for your time to put together comments, answers and suggestions to my questions. They are very good.
Comments:
Thanks for a good word about spindle nut repair. It was my initiation into BeoGram world :) So far it holds well.
As of fixed arm height it is now 23mm. I used screw "A" and after few touches I got 23 mm. After that I noticed that tone arm was a bit lower. I referred to your other post http://beolover.blogspot.com/2016/03/beogram-8002-adjustments-and-some-final-touches.html and fine tune tone arm to the point that by naked eye they look reasonably good.
Thanks for note about slack in the arm moving chassis suspension. This is good news.
Referring to another of your blogs: http://beolover.blogspot.com/2016/02/beogram-8002-strange-behavior-after-play-arm-moves-2cm.html I bought the same opto-resistors and similar LED diode. Again I want to thank you for putting those notes together. They saved me time on the same photo resistor investigation. Much appreciated. After this change and few adjustments, I now have 650mV on each of the opto-resistors when < << >> > buttons are untouched. This matches BeoGram manual recommendation.
I would agree that replacing stylish B&O logo at the end of tonearm with red dot was not a great decision that B&O designers made. It's a bit late at this point to complain about it so I'll live with blinking LED :)
I really appreciate your help here. And just so you know I also looked at this blog: http://beolover.blogspot.com/2015/12/beogram-8000-installation-of-new-rubber-bumpers-on-hood.html and now my BeoGram cover has rubber fits back :)
Few more questions:
1.
As regarding tacho disk I already exchanged few emails with Martin (Dillen) and new stainless steel tacho disk should be on its way to my post box. I found your post http://beolover.blogspot.com/2017/06/beogram-8000-replacing-platter-tach.html that outlines tacho disk replacement. Is there anything that I should pay attention too while doing this job?
2.
After replacing photo-resistors, the arm after PAUSE still does not return to its pre-PAUSE position. Please have a look at this video: https://www.dropbox.com/s/6gmtsex40ydhovs/P1170490.MOV?dl=0
I think this might have something to do with your comment:
"The tangential drive motor should advance after the initial arm drop down in 2 +-1 platter revolutions. Then every platter revolution after that." Would you agree? If so should I play with this adjustment?
What I'm talking about here is that when arm is dropped, fixed arm moved away from it a bit. Then when arm is lifted, it does not lift vertically but at an angle. To me that is the reason why after PAUSE when needle return to the record it returns to the top of the angle movement (if that make sense to you :) Do you have any suggestion here?
3.
You asked about arm lowering movement. I tried to capture it on those two video clips:
https://www.dropbox.com/s/agf5073zry6kg1c/P1170487.MOV?dl=0
https://www.dropbox.com/s/9ep3js0glfg3tuu/P1170489.MOV?dl=0
To my untrained eye dropping is reasonably smooth, lifting is a bit rough but I'm not sure if this supposed to be like that or not. What do you think?
4.
I replaced all aluminum capacitors except one in transformer compartment which is 39uF. It is bipolar cap and I do have 4 polar 39uF capacitors to make one 39uF bipolar one but I wonder is this worth the effort. What would be your advice here?
Thanks for your time and help and have a nice day,
mhenryk: Few more questions: 1. As regarding tacho disk I already exchanged few emails with Martin (Dillen) and new stainless steel tacho disk should be on its way to my post box. I found your post http://beolover.blogspot.com/2017/06/beogram-8000-replacing-platter-tach.html that outlines tacho disk replacement. Is there anything that I should pay attention too while doing this job? 2. After replacing photo-resistors, the arm after PAUSE still does not return to its pre-PAUSE position. Please have a look at this video: https://www.dropbox.com/s/6gmtsex40ydhovs/P1170490.MOV?dl=0 I think this might have something to do with your comment: "The tangential drive motor should advance after the initial arm drop down in 2 +-1 platter revolutions. Then every platter revolution after that." Would you agree? If so should I play with this adjustment? What I'm talking about here is that when arm is dropped, fixed arm moved away from it a bit. Then when arm is lifted, it does not lift vertically but at an angle. To me that is the reason why after PAUSE when needle return to the record it returns to the top of the angle movement (if that make sense to you :) Do you have any suggestion here? 3. You asked about arm lowering movement. I tried to capture it on those two video clips: https://www.dropbox.com/s/agf5073zry6kg1c/P1170487.MOV?dl=0 https://www.dropbox.com/s/9ep3js0glfg3tuu/P1170489.MOV?dl=0 To my untrained eye dropping is reasonably smooth, lifting is a bit rough but I'm not sure if this supposed to be like that or not. What do you think? 4. I replaced all aluminum capacitors except one in transformer compartment which is 39uF. It is bipolar cap and I do have 4 polar 39uF capacitors to make one 39uF bipolar one but I wonder is this worth the effort. What would be your advice here? Thanks for your time and help and have a nice day, Henryk
1. The tacho disk replacement is pretty straight forward. The disk is held in place by a large, round retaining ring. You need to be careful and patient with removing that retaining ring. You will probably need to re-use it.
2. & 3. In your videos it looks like the sideways adjustment move that the arm makes might be due to the tonearm being slightly out of parallel with the fixed arm. Looking at the arm from the front and with the black, plastic housing removed there is a large brass, screw head visible on the left side where the fixed arm is. That is the connecting screw the arm lift operates on to lower and raise the tonearm. Turning that screw head adjusts the parallelism of the tonearm to the fixed arm. It looks like the current position is not where the tonearm wants to be when it is lowered and in a record groove. So as soon as the arm is lifted that connecting screw pulls the tonearm back to where it is set to. Adjust that position just a hair so the arm lowers and raises vertically straight. As far as the return from pause that vertical misalignment would be a factor. However, if a record's center hole is slightly off that will mess up the return play accuracy as well. I have never found the pause and return accurate enough to be used for anything but convenience when I get a phone call while listening to a favorite album. 4. You can make a bipolar capacitor replacement for the capacitor in the transformer box using two polar capacitors that add up to 39uF. Personally I like using Beolover's replacement part for that capacitor as it has the 3D printed holder that fits perfectly in the transformer.
Hope that information helps.-sonavor
Thanks for comment. Much appreciated.
I’ll pay attention to retaining ring when replacing tacho disk.
Adjustment to the screw you pointed me to did the job. Now arms lovers and lift vertically straight and angular movement is gone. One interesting thing to look at here is rotation of moving chassis motor. With screw properly adjusted there is no speed up of that motor at the beginning after arm being lowered onto the record. I think I got this to the best possible adjustment and with your comment I’m happy with what I can get from PAUSE/return functionality.
The 78uF capacitor (which will be 39uF x 2) is not a standard value. That’s why I was talking about 4 caps here.
Last two questions Sonavor (I know I’m begin to be annoying…).
1. When you look at this movie clip would you consider lowering movement of the tone arm smooth enough or should this be smoother? https://www.dropbox.com/s/ictvo4c46oqerg6/P1180487.MOV?dl=0
https://www.dropbox.com/s/0l9cr3p1m2t30j2/P1180485.MOV?dl=0
I think it is fine but maybe I’m getting paranoid here :) What would be your personal opinion here?
2. There is a small brush that supposed to clean the needle after moving chassis parks in its compartment of the Beogram. Would you have any recommendations for setting of that brush? Should I fine tune that brush in any way or form?
I’m getting to the point when I will consider this BeoGram project finalized. This is greatly thanks to your advices here for which I’m very grateful.
Thanks,
mhenryk: Last two questions Sonavor (I know I’m begin to be annoying…). 1. When you look at this movie clip would you consider lowering movement of the tone arm smooth enough or should this be smoother? https://www.dropbox.com/s/ictvo4c46oqerg6/P1180487.MOV?dl=0 https://www.dropbox.com/s/0l9cr3p1m2t30j2/P1180485.MOV?dl=0 I think it is fine but maybe I’m getting paranoid here :) What would be your personal opinion here? 2. There is a small brush that supposed to clean the needle after moving chassis parks in its compartment of the Beogram. Would you have any recommendations for setting of that brush? Should I fine tune that brush in any way or form? I’m getting to the point when I will consider this BeoGram project finalized. This is greatly thanks to your advices here for which I’m very grateful. Thanks, Henryk
The videos of the lowering look like the electronic solenoid operation is working. Yours does have a slight drop right before touchdown which I don't see on mine. It isn't severe but you might observe the lowering mechanism as seen from the side in some photos I posted here. The connecting screw (that you adjusted) should follow the solenoid driven arm smoothly all the up until the lowering bar is clear from it. That point is when the stylus touches down on the vinyl. The lowering bar continues to go up a little so the tonearm is free to move on its own. Like I said, your videos of your arm lowering look pretty good and that may be as good as you can get that one.
My personal choice is to remove the brush. I know the B&O engineers knew what they were doing but with the cost of cartridges I would prefer no extra side force on the cantilever. I clean my stylus once in a while with a small piece of MagicEraser. I do that by lowering the stylus directly on the eraser (never moving the eraser). Any particles on the stylus will stay on the eraser pad.
Nice work on your restoration.
I was thinking about the arm lowering again and if I were you I would go ahead and add a small plastic material between the arm height adjustment screw and the bottom of the tonearm counterweight. I use DuraLar but other similar materials would work. It should ensure you don't run into the arm lowering issues in the future and now is the time to do it while the Beogram is opened up for service.
As always, many thanks for your comments and suggestions.
I’ve checked your brilliant post: http://beolover.blogspot.com/2019/01/beogram-8000-type-5613-service-manual.html
I followed your advice and add little plastic material underneath of tonearm counterweight (where screw touches counterweight). I didn’t have DuraLar. I used small piece of mobile phone screen protector (foil like one). It does the job and after re-adjusting screw, arm is levelled again.
In your post you pointed out to cartridge force mass. I didn’t play with that adjustment at all assuming what was set there was correct (it was set to 1 gram). But your post got me thinking so I looked what is the correct mass for MMC20S cartridge. I found this page: https://www.beoworld.org/article_view.asp?id=205 and in it, it states that it should be set to 1.5g. This is what I did, I checked everting with tip scale and I got 1.50 there.
After that adjustment, tone arm lovers in rather smooth fashion. So again, thanks for great article.
I also received tacho disk from Martin and installed it. It is a bit delicate job and putting new disk back was more difficult than taking older one out, but it is all good now. BeoGram keeps revs very well with new metal tacho disk.
Yourself as well as Martin recommended to not use brush for cartridge clean so this is what I did. I lowered it to the point where it does not touch tip any more. Now it just serves decoration purpose. I would have to buy myself MagicEraser when I’m in states next time. This seems to be very American thing :)
One note on the BeoGram detector arm red LED functionality (in BeoGram 8000) that I came across in one of the user guides. When you press PLAY second time player will repeat the record. This fact is confirmed by small LED blinking during first record run. Not very intuitive but here you go :)
Again thanks for good words. There is no more questions from me in this post :) At this point in time BeoGram is in one piece with all components in place and plays well. This is heavily thanks to your help here (and in your blog posts). I do appreciate that.
Many thanks,
Your are most welcome Henryk. It looks like you are set for many years of great service from your Beogram 8000.