BeoGram

Re: Beogram 4000 too hot?

Step1 — Mon, 22 Nov 2010 11:10:58 GMT

Tom I would consider starting a new thread requesting help if I were you. There must be known trusted people able to competently tackle the 4000 within a reasonable distance!

Re: Beogram 4000 too hot?

Tomkellett — Mon, 22 Nov 2010 09:24:15 GMT

Anyone recommend a good place to get it serviced.

Im based in South london

Thanks

Tom

Re: Beogram 4000 too hot?

Step1 — Thu, 18 Nov 2010 19:29:31 GMT

If you are not sure of it's history then it will almost certainly need a service.

Lots of little things could add up and cause the problems you describe.

Bare in mind while your cartridge looks A1 the suspension could be on it's way out which may give many of these symptoms.

Also have you checked the tone arm weight with scales? Does the tone arm move freely without the stylus being strained? (look for cantilever movement when playing records - (this could also indicate knackered stylus suspension).

There could also be a problem with the flexible wire loom between tonearm assembly and chassis. This could also tie in with variable volume levels and rubbing noise - things are quite tight under the platter.

I highly recommend getting an experienced B&O restorer to give the thing a full service as per the manual and maybe capacitors / big resistors as mentioned above. Do not send to someone who hasn't had experience of these machines - Too many things to go wrong! I recently got a deck where a previous tech tried to prise the plates up

Re: Beogram 4000 too hot?

Tomkellett — Thu, 18 Nov 2010 18:38:23 GMT

Hi, as a follow up. Ive been using my BG4000 sparingly and keeping an eye on it.

Ive noticed that there seems so be a bit more crackle now. The cart is in perfect nick, so it cant be that.

Also ive noticed that occasionally it can make a slight grinding sound when the arm returns.

Also very occasionally, the beginning of the record can sound all over the place. With volume and sound quite erratic until maybe the second track starts.

Guess this all wont sound too good. Maybe i need a service. Any suggestion?

Cheers

Tom

Re: Beogram 4000 too hot?

Step1 — Sun, 14 Nov 2010 03:34:24 GMT

Ah ok thanks - will take a look!

Re: Beogram 4000 too hot?

yachadm — Sun, 14 Nov 2010 00:34:29 GMT

OK, that's a different angle - those big carbon resistors on the BG400x have generally lost their resistance - have you checked it?

I'd recommend replacing it with a 2W - 5W ceramic unit. Those handle the heat much better.

Remember, in those days, a 1W resistor was pretty much pushing the limits of technology ;-), and carbon was all there was.

On a restoration of these units, I replace all those resistors without even thinking twice.

Menahem

Re: Beogram 4000 too hot?

Step1 — Sat, 13 Nov 2010 18:05:22 GMT

Actually the big 1 watt resistor and zener supplying the base of the transistor kicks out a fair bit of heat - definately not the motor as this is setup exactly as per the manual (I followed just about every proceedure to get things just right :) ). The transistor has to drop about 10volts or so if I remember correctly. The regulated side is a little lower than the 24V specified but I think that is to be expected.

I should also say the player is on top of my amp (with adequate spacing) so there is also residual heat from this, which does skew things some what!

Anyway I hope I didn't ride over your post at all, it wasn't intended (I didn't see it tbh).

olly.

Re: Beogram 4000 too hot?

yachadm — Sat, 13 Nov 2010 15:53:56 GMT

Step,

If you check your TT, you'll see that it's not the transistor which is heating up, but the actual motor! You should really readjust the motor current to run at a lower voltage - see the Service Manual.

And if it is the transistor heating up, you've got a definite problem in the control circuit.

Menahem

Re: Beogram 4000 too hot?

Step1 — Tue, 02 Nov 2010 10:16:23 GMT

Tom I think 8 hours is a bit on the unprecidented side if there was a problem things would heat up quite quickly. My 4000 also gets warm on the bottom left due to the transistor embedded into the chassis next to the motor!

The man to see about your caps is Martin as he does a kit so give him a PM. Caps also available from the likes of CPC, Farnell etc... but it is a bit of a mine field for non entusiast!

In my 4000 I replaced a couple of capacitors one in the detector circuit and can't remember where the other one was. I probably should do the others and PSU caps but haven't got round to doing this yet!

Re: Beogram 4000 too hot?

yachadm — Tue, 02 Nov 2010 10:13:26 GMT

If you play it for extended periods and it really heats up, you run the very real danger of toasting the actual circuit board. That makes your BG4000 a beautiful door stop.

If you play 1 LP, switch it off, wait an hour, play another, I wouldn't worry - the worst case is that you fry a transistor.

I have all parts necessary to repair it. The question is whether you have the sills and equipment necessary to execute the repair, without causing any damage! Or do you intend to have a very trusted tech do it?

I can overhaul the PCB, but you'd need an average grade tech to remove it for shipping to me.

Menahem

Re: Beogram 4000 too hot?

Tomkellett — Tue, 02 Nov 2010 09:59:40 GMT

Cheers for your replies guys.

Can I ask? Will it ruin my turntable if i don't change them now and wait for it to get worse? I've been using the turntable a few times since and although not for along as before. It doesn't seem to be getting hot very fast. If i do need to do the work, can i do it myself? And would you have an idea where i can get parts from, or are they common and available in maplins?

Thanks again Tom

Re: Beogram 4000 too hot?

yachadm — Wed, 27 Oct 2010 09:29:42 GMT

Hi Tom

You need to replace the capacitors, as Martin mentioned. Then having done that, if the problem remains, you need to measure the main rail voltage on the main PCB.

If there is still more than about 1.5V deviation from the voltage specified in the Service Manual, you need to look at replacing the power supply regulation transistors.

Take a look at this pdf of my BG4002 (yes, I know your's is a BG4000, but there are still many similarities in the circuit). Pay close attention to Section 7.

http://www.condoraudio.com/wp-content/uploads/Projects/BeoGram-4002-6000-Turntable-Restoration-Repair.pdf

Let us know how you get on.

Regards

Menahem

Re: Beogram 4000 too hot?

Dillen — Tue, 19 Oct 2010 16:04:05 GMT

It will probably soon need new capacitors, that's quite common but it's also quite common to see
the Beogram 4000 running a bit warm so yours may still be fine.
The weak (and warm) power supply circuit was one of the things that was corrected in the later
Beogram tangential versions.

Martin

Beogram 4000 too hot?

Tomkellett — Tue, 19 Oct 2010 13:46:19 GMT

Hi,

I have been using my Beogram 4000 for the last few years without any issues.

Last weekend i had some freinds over and we were playing records for around 8 hours non stop.

I noticed that after say 5 hours or so that the deck was getting quite hot indeed.

I had been playing with the lid down, so after i continued but with the lid up.

Everything seems ok still, but is this normal? or is there anything i should do?

Thanks

Tom