As a collector of Tandberg tape recorders - I have over 20 - I have been stumped by a recent repair I did. I replaced the grid capacitors, namely the .022uF and .047uF capacitors on the playback and record boards only (since they are valve based) because the original Rifas tend to leak. I didn't do anything else. The unit works fine... both L and R record perfectly but when played together in stereo the sound is out of phase. Reverse a speaker wire and it sounds fine. The are no obvious errors - none of the head or input wires have been mixed up. It looks as though one of the capacitors is doing it but I've never heard of such a thing. Could it be the cross field bias? A faulty valve - although they were replaced with new? The fault is on the record board - playback of prerecords is fine. Any ideas you fine people?