Ok here's the problem, hope you guys could help me out.

 Just received me Beogram 1000 (£140- ouch) to hook up with my Beomaster 1000 (£7.50 - that's better). Mind the record deck is in mint condition and has basically been in a box for 40 years. Cartridge and stylus are perfect.

 With the record player plugged into input 2, when playing a record, if the MONO button is not pressed down (ie it should be playing back in stereo), the sound only comes out of the right channel. However if the MONO button is pressed down (ie it should be playing mono) we get sound out of both speakers, but as far as I can tell it is not stereo, what I mean is it is the same sound coming out of each speaker and it is playing in mono, so this side of the button seems to work.

 I think it may be a channel out on the pre-amp and i tested this by plugging the deck into the Tape input and although, obvioulsy, the level was low, there is sound coming from both speakers in a true stereo fashion.

 Does anybody have any ideas ?

Seems like you've proved the beogram is okay. Also that the preamp (tone controls) and power amp in the beomaster are okay. Assuming that the Gram2 socket is fine (first and easiest check!) that leaves the preamp (RIAA) .

If your beomaster is the white plastic version, the RIAA will be on a separate board plugged into the main board - checking that it is properly seated would be the next easiest thing to check. If you have the grey plastic version then the RIAA will probably be integrated into the main board, which wouldn't be quite so easy to sort out.

Cheers, Steve

You haven't got the speakers plugged into right1 and right 2 have you?

Oh, and welcome to Beoworld

Andy T.