viark sat 4k issue on v polarity channels.

hey guys ive a viark sat 4k box i use a 4 way diseqc switch and i,ve got my motorised dish on diseqc lnb1 all fine,but my sat channels on 28.2e with the diseqc switch on number 3 lnb 3 is fine with horizontal channels and gives no signal on vertical channels on 28.2e now this is very strange as i had this setup with another box which was fine.
but all of a sudden since i got the viark sat 4 k box its just not working right on the vertical channels on a fixed sky dish that is perfectly alighned on 28.2 e

any ideas as to why the horizontal are fine and the vertical no signal going through a 4 way disqec switch that was working perfectly with previous box set up.

also if i move my motorised dish to 28.2e then i get both H and V channels.

only get the problem when i switch to my sky mini dish fixed on 28.2e thats on the lnb 3 on the 4 way diseqc switch.

although that sky min dish is over 20 yrs old i wonder is it the lnb on the sky min dish,i will check tomorrow by wiring the mini dish straight to several receivers and trying both H and V channels.