What could be wrong with my receiver, regarding phase ?

[rijnton]

I have my speakers bi-wired, that is tweeters to the B output and woofers and mids to the A outputs. Probably unnecessary sound-wise, but I also tested leaving the tweeters not-connected. Same result. With the battery I only checked the woofers and the mid-range speakers indeed.

I also listened to fm mono and with speakers wired correctly it is not centered but diffuse.

 

[mtrycrafts]

I have my speakers bi-wired, that is tweeters to the B output and woofers and mids to the A outputs. Probably unnecessary sound-wise, but I also tested leaving the tweeters not-connected. Same result. With the battery I only checked the woofers and the mid-range speakers indeed.

I also listened to fm mono and with speakers wired correctly it is not centered but diffuse.

That is not how bi-wire works. That may be your issue. Try both wires from the A terminal. This should have been also posted in the 1st or the 2nd explanation post.
Actually, you should just eliminate the buy-wire method altogether and run it with one pair of wires. You see what happens?

 

[rijnton]

Actually, you should just eliminate the buy-wire method altogether and run it with one pair of wires. You see what happens?

But that is what I did imo, by only using the A terminals and connecting them to the LF inputs of the speakers, although the tweeters are not in use then of course.

But meanwhile I took the plunge en bought a new one. I didn't feel like taking all the trouble to have the receiver checked, costing money of course, and then most likely have it repaired afterwards. That would also mean being without a receiver for several days or longer.
I bought the Yamaha RX-V863. I could have bought the cheaper 663, but that was not in stock in the color I wanted. Moreover it was a very special offer.
Anyhow the new receiver is working perfectly. Much better sound then the old one. There is also a genuine possibility for bi-amping, using the back surround amp (for 7.1) in a 5.1 system.

 

[TLS Guy]

But that is what I did imo, by only using the A terminals and connecting them to the LF inputs of the speakers, although the tweeters are not in use then of course.

But meanwhile I took the plunge en bought a new one. I didn't feel like taking all the trouble to have the receiver checked, costing money of course, and then most likely have it repaired afterwards. That would also mean being without a receiver for several days or longer.
I bought the Yamaha RX-V863. I could have bought the cheaper 663, but that was not in stock in the color I wanted. Moreover it was a very special offer.
Anyhow the new receiver is working perfectly. Much better sound then the old one. There is also a genuine possibility for bi-amping, using the back surround amp (for 7.1) in a 5.1 system.

So obviously your old receiver had serious problems. Passive bi amping like bi wiring is a complete waste of time. Forget it.

 

[rijnton]

Passive bi amping like bi wiring is a complete waste of time. Forget it.

But does it have any disadvantages ? I do have already van den Hul "The Teatrack" cables, consisting of 4 leads and I have a 5.1 system. The B&W speakers have separate HF and LF inputs and Yamaha suggests use of the bi-amping option in the manual in such a case.
I mean, cant I assume that it may not help, but its doesn't harm either ?