Could be that it just needs a firm push on the reset knob.
It's quite normal to see that the counter locks in some way if not reset correctly, sometimes also
with a ticking sound as the reels rotate.
Alternatively, check the counter belt. Easily done by simply pulling off the aluminum cover.
I can supply new belts if you need but check the counter reset first.

Martin

OK,thank you Martin,is the counter belt about 1 mm wide and 34 cm long? a belt like this fell out off the R2R when i lifted it out off the box it was shipped in.

Jon

Surely something to do with this problem even if not quite the correct size.
If it is the original belt, it has deformed and/or stretched (and probably broken by now), that's very normal.
- Or something that someone tested in there - and it worked until it came off in transport.
You could try mounting it again if not broken.

Martin

Yes its probaly the missing belt that causes the problem then,the belt that fell out had snaped off,so i have to get a new one.

Jon

If one of the belts snapped, the others are probably marginal as well.
A belt set is available for the Beocord 1200 (and also one for the very similar Beocord 1600).
You have a PM !

Martin