[sonavor]

Great. You meant to write that you got through your BG8002 restoration, right?

Congratulations and good work.

-sonavor

 

[sonavor]

If you used something like an OP240 or OP245 IR Emitter then their corresponding phototransistors are OP550 or OP 560 for the OP240 and OP555 or OP565 for the OP245.

The IR Emitters have been hard to get for a while but fortunately you already have that component.

Before changing any of these components I would measure the existing signals and make sure the part is where the fault is.

-sonavor

[sonavor]

Sorry, I didn’t read the previous threads closely.
It sounds like you have set the steady-state levels on the scanning buttons where the LDRs measure 620 mV.

I would connect an oscilloscope to the sensor signals and see if any are showing any signs of problems.

Here are the sensor measurements I captured on a Beogram 8002 a little more than a year ago.  The oscilloscope measurements are towards the end of the post.  There are also photos of where the test probe wires are soldered to.

-sonavor

[sonavor]

Have you performed the service manual adjustment for the forward and reverse scanning control buttons?
Both should measure around 620 mV at their steady-state (not pressed) position.
If those are adjusted correctly then perhaps you do have a problem with one of the position sensors.
Those can be replaced if necessary.  I believe Martin has a replacement part at the Beoparts store.

The source of the problem could still be elsewhere though.
To see what is going on for sure you would need to attach some probe wires to measure what the various sensors are actually doing.

-sonavor

[sonavor]

I haven’t done much wood veneering but I have used a product like this on reattaching metal trim on some Beogram dust covers.  However, there are quite a few different manufacturers of that type of glue.  I didn’t save the links but there “how to” videos on veneering as well.

I believe Craig, here on the Workbench, re-veneered his Beomaster 4400 a couple of years ago.

John

[sonavor]

Hi Jacques,

Yes, contact cement is what is usually used for applying a veneer to another surface.

John

[sonavor]

Hi Jacques,
Yes, I learned a ton from you and the other Workbench regulars.  I owe you guys a big thanks.  With Martin guiding us when necessary we accomplished and learned a lot.

I still do a lot of restorations but on a blog now.  For me it allows for a better structuring of the restoration story and the presentation has better media (photo) options.

I think that restorations have increased now.  Martin’s Beoparts store has some really great parts a DIY restorer can find and use so I think there is a lot going on.

John

[sonavor]

Yes, nice work Jacques.

[sonavor]

I have fixed the BG400x sticking solenoid problem like this.  The information on the solenoid is towards the end of the post.

-sonavor

[sonavor]

Hi,

The Beomaster 8000 has a lot of interconnect cables inside. It is possible that handling of the Beomaster during the move caused one of the internal cable connections to disengage.

-sonavor

[sonavor]

The springs have a damping sponge inside them.  They should be left in.

Operational problems with these turntables after 40 years is common.
There could be oxidation on the operating buttons.  Capacitors on the main board may be out of tolerance.  Sometimes there are faulty transistors.  Mechanical adjustments need to be made per the service manual.  Sensor lamps might need replacing.

You can look up a lot of information about servicing them here.

-sonavor

[sonavor]

Yes, as Martin mentioned earlier, the aluminum frame piece wedges the grill cloth in place.  They should fit nice and snug in the plastic frame just like the original was.

-sonavor

[sonavor]

I have a post on the old version of the forum that shows doing that.
I will try and find it and post the link.
You have to be very careful with the aluminum trim and just bend it a minimum amount to release it.  Otherwise, bending out straight will most likely cause the trim to break off at the bend seam.

-sonavor

[sonavor]

Here is a link to the page on the old forum.
It was on a post I did restoring some Beovox MS-150 speakers.  They are larger but have the same cabinet/grill design as the S120’s.
The photos – beovox_ms150_grill_00.jpg, beovox_ms150_grill_01.jpg, beovox_ms150_grill_02.jpg and beovox_ms150_grill_03.jpg show the different stages of the grill disassembly.

The disassembled photo at the end shows the successful removal of the aluminum trim with it still intact.

-sonavor

[sonavor]

If you are going to buy a capacitor kit then buy it from Beoparts.  Same for belts and lamps.
I am in the USA and I buy plenty of replacement parts from Martin’s Beoparts store.  They usually only take a week to arrive.

-sonavor

[sonavor]

Strange behaviors like that are common for Beogram 8000 and 8002 turntables that need restoration.  It’s difficult to say offhand what the fix for the symptom is because there can be several problems going on.  The problems result from bad information from failing circuits reporting what is going on back to the Beogram microcomputer IC.

For certain you want to begin with replacing the old electrolytic capacitors.
While doing that you should reflow solder joints of all the board connectors.
Once those things are done you can retry and see where your Beogram is at.
It is a good idea at that point to measure all of the key power supply voltages and perform the service manual adjustments.
I also like to check the health of the sensor signals (using an oscilloscope).
Those steps should catch any problems.

I hope you sourced your servo belt from Beoparts.

-sonavor

[sonavor]

spassmaker wrote:

Hi One thing I’d like to mention is that, if you’re cleaning the wormgear be very carefull with solvents like contact cleaner, thinner or acetone, the black coating of the chassis is not very resistant against solvents and will be solved and looking very bad…. Put some papertowels under the wormgear and exchange from time to time while cleaning. Don’t ask me why I know this ;-)) Regards Christian

Yes, even isopropyl alcohol will start stripping the black coating on the base of the cabinet.  Don’t ask me why I know this either. 😉

-sonavor

[sonavor]

From your photo the spindle doesn’t look bad.
When you say reluctant tonearm assembly what do you mean?

How old is the servo belt and did you get a proper one from Beoparts?

A worn or incorrect belt is the source of a lot of problems.

If you have an arm assembly that moves a short way then seems to hang up (and the belt is not the problem) then it is likely a problem with the electronics controlling the servo.
Old capacitors, bad connection somewhere and, sometimes, faulty photo sensors.
There are also two adjustments on the control button panel for the left and right scan control.  The service manual specifies what the steady-state voltages need to be for those two controls.  If they are not correct they will cause problems with the arm assembly movement.  If you dive deeper into the related threads I linked to there should be some posts about those scanning sensors.

If the BG8002 is still operating on original electronic parts then circuits could be trying to operate with out of tolerance components (like electrolytic capacitors that are no longer in spec).

-sonavor

[sonavor]

Hi Wallygator,

Here are three different posts that have detailed photos of the BG8002 spindle components.
BG8002 1

BG8002 2

BG8002 3

I don’t know what your capabilities are so I will just warn you that if you are not mechanically inclined I wouldn’t attempt to disassemble the tangential arm assembly spindle.

The first step is to remove the servo belt.
After that you rotate the spindle so the slotted, black plastic wheel is lined up so the small photo sensor board can be removed.
There is a plastic spring clip holding that sensor board in position so you need to carefully release that.

The spindle must be released from the plastic clip holding it but that is not all.
The spindle has a nylon nut the drives the tangential arm assembly and it is attached to the spindle and arm assembly transport by a plastic clip that the bottom (shiny) rail fits through.  So you will be removing that as well.

I use plastic pry tools to detach the spindle and rails from their clips.

Just work slowly and carefully (and take plenty of before photos) so you know how things go back together.

Hope that helps.

-sonavor

[sonavor]

Because I caught the Beovirus many, many years ago (okay, decades ago) I have a pretty large collection of Beogram turntables.  I can’t bear to part with any of them as they all perform satisfactorily for me.

As was mentioned earlier, the cartridge and stylus are a big (biggest) factor in the resulting sound.  The platter stability and tonearm do play important parts of course but you have to begin with a good cartridge to start comparing the various turntables with.

Like Jacques (chartz), I prefer the tangential Beogram models.  My first one was a Beogram 4002 back in the 70’s.  I purchased a Beogram 8002 in the 80’s.  Since then I have been lucky to acquire Beogram 4000, various types of 4002, 4004, 8000 and 9500 tangential models (all restored).  I have two restored radial Beogram turntables.  A Beogram 3000 (Thorens + B&O) and a Beogram 5000.

My favorites to listen to are the Beogram 8002 and Beogram 4002.  Specifically the ones I purchased in the 70’s and 80’s.  I still have them and they perform like new, having had a bit of restoration work.

My favorite B&O cartridges are the MMC 20CL and the MMC-2.

I am just as happy listening to the other models however and what I think that means is Bang & Olufsen designed and built really good turntables that hold up over time if taken care of.

It’s too bad B&O didn’t retain their cartridge/stylus business and were still producing them today.

-sonavor

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