Sorry, I meant to say "lift". Maybe I should make a little movie. But it seems something is in the way of the arm lowering if the weight is shifted too much inwards :-(

Ok, she's done!

Absolutely flawless. This has better sound than all the BG4002's and BG6000's I've done. I am astounded.

And the cartridge is nothing special - an original B&O MMC20E.

I was thinking of putting in Cardas cables, but to be honest, I can't imagine what an improvement over this would sound like.

For me, this is my keeper TT - it's not for sale! Help, the BeoVirus is attacking!!!

Anyway, cosmetically it's beautiful now, after much elbow grease, but I need a new acrylic cover.

The sound on the movie is pretty pathetic, off my little camera..... Take note of the Display and 33/45 LED's - I think it looks pretty sharp!

BeoGram 4000 Restoration Play

May she last a lifetime and more.  Congratulations and well done! 

Yes I understand!

I love mine too; so much so that I'm selling my beautiful Technics/RB300!

Congrats!

Well, thank you, kind gentlemen

It was one of the most challenging challenges I've had, and to tell the truth, when I saw its initial condition, I wasn't hopeful. And if it had been a BG4002 or more common variety, I would have just parted it out.

But this one, being a BG4000, said - you can't give up on me.

Funny how they take on a life of their own...

I'm just listening to it now, thoroughly enjoying it, through my BM3400 and S45's.

You're a true master Menahem. Wish I could have some of your knowledge when it comes to electronics. Very impressive....

One small adjustment needed.

On some LP's, which have "extended play", the tonarm lifts too early at end-of-play.

I need it to travel another 3mm before lifting. Am I correct in assuming that it is contact A which must be adjusted, and moved 3mm to the right?

Yes, but those awful records are best forgotten! They were generally poor sounding... I have always refused to adjust any of my automatic decks to comply with off-the-norm LPs. Worth a try perhaps!

I had the same problem on one of my two BG 4000s. Somebody in here said that it wasn't these contacts as they supposedly only control where the arm should be lowered. Instead there should be a circuit detecting the run-out groove, meaning that when the arm travels fast, the circuit will give the command to lift the arm and return.

Filip,

I can't offer any opinion, because I don't know - that's why I'm asking.

Has it something to do with this adjustment?

Hi - yes, that's it. I'm sorry I didn't have the service manual at hand when I suggested you take a look at the circuit.

However, I have another question for the service manual. How does one do this: What is a bearing frame?

 

And also how does one get this tool for adjusting the lenght of the arm?

filip_kbh:

And also how does one get this tool for adjusting the lenght of the arm?

Hardly anywhere, unless you get to raid an old service establishment. You'll just need to duplicate its function somehow. For all that I can see, it is essentially a 90° gauge pivoted at the center of the platter.

On the other hand, I really don't believe there'll ever be any practical or audible difference if you just do those adjustments by eye. The goal is simply that the arm is perpendicular to the travel of the stylus, which should cross the center of the record.

Believe me, the eye is very, very accurate when it comes to define whether two arms are parallel or even slightly in/out!

BUT the black plastic of a record, when in contrast with the alu parts, CAN be misleading!

So trust your eye but don't get sick about it alright!

 

Here is a short film of my problem. As you will see the weight platter is too close to the arm, leaving no room for the arm to be able to lower. I suspect the arm was once replaced and that the platter was not - but how will I find out?

Anyway - take a look at the video here:

I suggest you use a tracking force gauge more suitable for the Beogram.
B&O made some nice ones that were included with some cartridges but
they can be a bit difficult to get hold of.
Something like this will probably also do fine:
http://www.amazon.com/Shure-SFG-2-Stylus-Tracking-Force/dp/B00006I5SD/ref=sr_1_1?ie=UTF8&qid=1317308043&sr=8-1

And then, don't trust the dial on the adjustment, it will be somewhat off by now.
Trust the gauge and never mind the dial.

Martin

But the thing is that even though I turn the dial to the max position (1.5) I cannot get more than 0.8 if I'm really lucky - and that is clearly not enough for any of the B&O styluses I have. The gauge is very precise and this is not a problem on my other Beogram 4000.

Bring it in for service.

Martin

It's worked flawlessly since I finished the restoration, but suddenly......

This morning, when pressing ON, immediately the solenoid activates and lowers the arm. ie, it doesn't wait until it reaches the beginning of the LP to lower the arm.

It plays fine, but when it comes to the end of the LP, the arm stays lowered, and drags the needle back across the LP (I caught that real quick!), and only raises the arm again at the At-Rest position.

Pressing the <, >, /\ or \/ buttons has no effect on lift/lower - ie the arm does not lift in response to these buttons when they are pressed.

Also, I connected the scope directly to the solenoid, and then pressed the /\ and \/ buttons - the waveform jumps, so the buttons are OK and their signals are getting to the solenoid.

So, something is forcing the solenoid down at application of power ON, and preventing the other normal circuits (buttons, end of LP position) to raise the arm appropriately.

I've checked for any broken wires / solder joints etc, but I need help to know where to start looking.

Menahem

I wish I could offer help; alas, I can't, but I offer best of luck.

My 4002 after service had many a night of flawless playback, one weird night where it had an attitude, then flawless operation since.  I hope my 4002 gremlin didn't find its way to your deck.

Solved .

Sometimes I don't do what I know I should do, and it prolongs the troubleshooting process. 

The AC versions of the BG4000, 4002 and 6000, all have a very similar circuit with regard to the solenoid activation of lowering the arm.

The /\ or \/ signal comes from the keyboard in a very similar way, and is then passed to the solenoid via 2 driver transistors (on the BG4000 1TR10 and 1TR11), and 3 on the AC 4002/6000 1TR14, 1TR15, 1TR16. 

I'd already had experience on the BG4002/6000 with the effects of these specific leaky transistors, which are badly stressed by the original large grey capacitors drying out.

Visually, in the past I have seen the immediate benefits of replacing these: having connected the TT via a 60W lamp in series with the main AC line, when the solenoid is activated, the lamp lights up indicating excessive current draw. Yes, the TT works, but it's not correct. Replacing these 3 transistors always caused a great improvement, with the lamp barely illuminating with the solenoid activated.

So here on the BG4000, as always, I connected the series lamp, and of course it lit up. But, I didn't think of applying my past experience to this circuit, until I'd exhausted the other possibilities of the FCH chips being faulty (which of course they weren't). 

Then I decided to replace TR10 and 11, just like I always do with the appropriate transistors on the 4002. Immediately after connecting AC, of course the solenoid didn't activate , and when it did (correctly) upon reaching the LP, the lamp barely illuminated.

Measuring TR10 after the fact showed an hFe of 9 (instead of about 150).

So, I can recommend when restoring these TT's, replace the solenoid's driver transistors without even thinking twice.

Menahem

Any chance you could tell us what types of capacitators/Electrolyts you have used.

I have two BG4000 decks and though they both work, I am worried about the caps, and I would like to change them. I hope this is not too difficult.

Electrolytics - Nichicon HE, Panasonic 220uF SU Bipolar, Panasonic TSHA (the 3900uF 63V to fit nicely)

4.7uF and smaller - Wima MKS2

Many resistors also required replacement, and as I mentioned also transistors and diodes.

I can put together a kit of most of the pieces for you - contact me offline.

Menahem

Very impressive work. Makes my own labours seem like a half-dead fish flapping around in mud

dauphine/andre