This forum is full of useful info to those trying to repair their own B&O TTs. I have lurked here a bit and researched repairs to 8000s. Mine is now fully  disassembled.  I will solder PCB connections, many breaks are visible.   My question is where to get new printed metal tachodisc; mine is the clear plastic kind, though appears to be in ok condition.  I have some new small electrolytics on hand that I'll use to replace old ones.

The turntable turns on, platter spins but arms don't move over, and display flickers. I have checked for obstructions in the back.  I'm pretty experienced w/ a soldering iron, though this is a more complicated PCB than I am accustomed to. Tracking force indicator is also missing. Marked corners. I probably can't sell this 8000 but would like to at least use it.

Thanks for any advice, 

Pete I

Denver USA

Pete,

Welcome to Beoworld !

I can supply the metal tachodisc. It's an exact repro part in stainless
steel, precisely fabricated to the hysterical tolerances needed to get it right.
PM me for details.

Does the servo motor try to rotate ?
Does it rotate if you take off the belt ?

Martin

Thanks very much Martin.  

I spent the day resoldering the PCB, cleaning parts, and replacing some capactors. Now the 8000 functions,  imperfectly, but it sets the cartridge down on the record. That's progress!

But, the tonearm moves inward every time it drops down.  Goes up, then when you hit Play, it moves towards the center of record about 5-6mm.  And it is not parallel with sensor bar when in up position. I see screw but will not attempt adjustments yet.  

I thought my DIN adapter would just plug into the back connector but apparently the terminals are different. So I really haven't heard music out of this TT yet. I need B&O's proprietary cable?

thanks to all who can advise.

Pete

Well, I seem to have figured out how to get the tonearm to work properly, scouring this forum as a resource. I adjusted the detector arm screw to the rear left. Now the two arms are parallel and the tone arm is dropping properly. It does seem to drop a bit fast, hard on the MMC 20CL.

I heard hum only, no music when connecting the DIN to phono of my amp, so i decided to adapt a pair of RCA phono jacks directly out of the back of the TT, bypassing the relay and DIN female plug.  Still no music, only hum.  Seems like the phono path is the absolute simplest circuit on this thing, yet it is the one thing that prevents my getting music from the cartridge on the record.  Grounded in the tonearm?  I'm stumped.

Pete

Nice progress so far! Good on you doing research and I assume using the search function!

You haven't mentioned what your amp is...

Are you certain it has an RIAA built in? The BG8000 does not ...before messing w/ the leads.

Short of that, has the cartridge been tested and known to be good?

The relay cannot break the connections from the cartridge to the DIN socket.
It can merely ground the signals.
Does it click apprx one second after the tonearm has landed on the record ?

Martin

The relay clicks normally, but I unsoldered the phono wires from the relay/DIN board, bypassing any problem there.  Ran direct to RCAs.

It appears my 20CL cartridge, with the sapphire cantilever, which I used on another B&O table, so I know it once worked, has no continuity.  It may have suffered a fall in a move, I haven't used it in 2 years.  Using tiny probes on the inside back, I tested for connection and there is none. Internal windings broken? The whole point of this project was predicated on having a ready system, if I could get the table running well, which i did.  Oh well, I won't spend hundred$ on a cart so I'll see if a used one turns up. I have found several at various local sales over the years, but sold them w/ tables. 

Cheers,

Pete

Wow, I've been trying to find out how or where to get my 8000 up and running again.  I'm really happy to have found this forum.   Speaking of hundreds of $'s to get it fixed, I was quoted $650 to get mine going!

Pete if you don't mind, I'd like to ask a few questions after I start opening my 8000 up.

My 8000 has always been finicky, but with a little button mashing would eventually work.  I found that pressing the "turn" for a few seconds followed by the "start" would almost always get it going.  As long as I used it on a regular basis it worked well.

A few days ago after not using it for a few weeks I tried to start it up and after the above mentioned sequence it would started up as normal, played a few seconds and then abruptly picked up the cart and returned to the off position.  When I tried to restart it it only moved the arm(s) a fraction and the light on the sensor arm would flash on (along with the rpm readout "00.00") then off.  After several seconds you could hear a small noise and get the flashing again.  And that's pretty much all it will do now.

Any thoughts on where to start would be appreciated.  By the way I don't mean to thread-jack, this just seemed to be the best place to start.

Thanks in advance,

ross

I'm not really the person to ask, there are others here far more experienced. I have worked on many TTs, but only a couple B&Os, such as old 3000, and 1200.  For this Beogram 8000, I used general electrical knowledge from working on tube and SS amplifiers and gear.  The advice repeated over and over here on this forum from generous expert Martin and others is to remove PCB and resolder cracked joints around the board. In my case, most were at the transformer connection. I replaced power supply capacitors and few others; seemed to help.  It's complicated to disassemble, not for the faint-of-heart.  Read as many posts on the Beogram forum as you can.

I'm sure someone will jump in a offer suggestions.

Best of luck, 

Pete

anyone have a crummy old MMC 20E to sell or trade, so I can at least hear music from this table?

Ross,
Welcome to Beoworld !

Sounds like your Beogram has one or more of the standard issues.
You can read A LOT about this if you do a search in the fora as Pete suggests but I
can also line the most common faults in the Beogram 6006, 8000 and 8002 up here:

- Capacitors. They dry out and/or leak.
A kit is available for convenience. Should be replaced in all decks.

- Tachodisc. That's the optical speed encoder disc that sits around the hub under the
platter and black subplatter.
If you have the photographic (printed plastic) type, the pattern will be falling
apart causing unstable platter rotation (wow), humming from the motor and
in severe cases flashing display digits.
New repro tachodiscs in stainless steel are available.
If your tachodisc is already a metal type, there's no need to replace it.

- Subplatter scraping on the floating chassis due to breakage of the tiny nylon
insert in the platter hub main bearing. This happens if the Beogram was transported (or shipped)
with the heavy platter installed. (Always pack the platter separately - wrap it in bubblewrap and place it
under the Beogram in the shipping carton!).
Repro nylon part available.

- Cracked solder joints. Especially in the power supply area, at the edge connectors and
ribbon cable and at the processor socket.

- Carriage binds due to wrong and/or dried out lubricants on the threaded shaft and
carriage bushings.

- Worn servo motor belt.
Also available.

PM me for parts details.

Martin

Pete,

Thanks for your reply.  I do have a question for you as you have replaced the b&o what-ever-it's-called connector with rca's.  My b&o cables are junck.  I have a phono input on my pre-amp, so I assume I'll just have to hook up the right and left channels and keep the ground?  Can you post how you did it? 

Martin,

Thank you also for your help. 

- I plan on doing the caps last. 

- The tachodisc is the metal kind.

- There doesn't seem to be any scraping or problem there.

- I did a quick look at the solder joints and other than some corrosian they seem fine - I'll remove the boards and use my magnifier/light to check for sure.

- Carriage seems to operate smoothly, what type of lube is best to use?

- Just replaced the little belt which helped a bunch.

While I was pulling it apart I noticed that the back panal connected to the dust cover and metal cover was more or less toast.  Are there replacements available?  I also need the mechanism that holds the dust cover up too.

I then started to "set up" the detector and pick-up arms per instructions which seemed to go well.  I got to the point of setting the pick-up arm balancing and realized that I have no idea how to lower the pick-up arm.  How do you do that?

Thank you again for your time and patience, I very much appreciate it.

ross

ps. boy do I miss spell-check!

As a matter of fact, now the pick-up arm doesn't want to fall at all.  Upon "play" it moves to the correct spot and drops a tiny fraction and stays.  When I hit "stop" it pops back up to were it's supposed to be and returns.  Any thoughts?

Thanks again...

ross

If your B&O cable works for the time being, why not use it. I only put in RCA jacks for testing purposes, they are not properly attached. I used an alligator clip lead for ground. I have yet to sort the proper way to do this.

Pete

Clean the threaded shaft and the carriage nylon bushing and add a couple of
drops of acid-free oil. f.e. sewing machine oil of the type that evaporates in months
rather than hours, to the shaft.
On the Beograms that come here, I like to use a type of oil that is normally used
in aviation instruments. It will work for a very long time.

Yes, use a microscope to check the solder joints.
If the board was not already re-done, it will have at least 30 cracked joints.
Most have more.
I like to use solder with a hint of silver in it to prevent it from cracking
again soon.

You should never touch the rear plastic panel unless absoutely necessary.
It's not necessary to take off the rear cover to gain access to the innards and
even the dustcover and metal plate hinge can be replaced without touching it.
It will just break or even shatter in hundred pieces if you try to unlatch it.
There are no machine specific parts available from B&O for these decks.
You will have to repair what you have or find parts from a donor machine.
The rear cover can be permanently fixed using 2-comp. epoxy. It will never come off
again but won't have to either.

While repairing, I use an old MMC cartridge with no needle.
That will allow for safe testing of the mechanics and controlling electronics
without damaging an expensive stylus while at the same time providing the correct
tracking force (cartridge/tonearm mass).

With the old caps still in, you will have to check the power supply voltages to make
sure that suitable operating conditions are present for the rest of the
electronic circuits. Use an oscilloscope and a multimeter.
The Beogram will not be able to perform correctly if it receives
too low voltage or too much ripple on one of the secondarys.
Deciding to leave the old caps in the board will make diagnosing very difficult
and other given faults will be very hard to find.
90% or more of the faults in these machines are caused by aging capacitors so I would
recommend you start there.

Martin

Aaaww...Crap!

I was hoping the do the caps this winter.   I wish I hadn't taken off the back cover too...

I did find in the packaging that the tacho thingy was replaced (the old plastic one was there in pieces) and also there was a seperate schematic with a few miscellaneous part #'s and prices, so maybe some work on the boards has already been done?

Martin, I'll pm you for the cap kit.  The only problem is I don't see how to "pm" you?  Do I "start a conversation with" or "talk about"?

So I take it that there is no "magic" to getting the tone-arm to drop?

There could be something physically blocking the tonearm and/or solenoid, preventing it from dropping. I cannot tell you exactly
what and where, sometimes a cartridge protective cap, a screw or some other object, maybe even an old cartridge is found
rattling around inside, but it could also be an electronic fault. The solenoid is driven by a ramp voltage.

PM = Start a conversation.

Martin

I'll validate: replacing the caps got both my 8002s behaving. 

Surprisingly, I found no broken solders in either. #3-solder city!