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

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.

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

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

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!

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

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.

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

Ah ok thanks - will take a look!