SMS 2 50/60 Hz mod issue...help please

Yesterday I modded an sms2 with rca output and 50/60 switch...everything worked and I tried many times to switch between 50 and 60 hz without any problem.

Today after connecting my sms2 to a sony pvm I got black screen in 50 hz mode, also on another crt got the same problem....I reopened the console to see where was the problem and I also changed the switch but really cant get a solution...I would take ground from everything on the pcb but when I put on 50hz it got black then if I put the switch on 60 hz console restart from sega logo...
is not a big problem cos it is stucked on 60 hz which is better than 50 hz but I would like to figure it out where te problem is....dont know if some contacts can make this happens

many thanks

 

Pal sms2 or ntsc sms2?

 

is a pal sms 2, I solve it after doin some resolderin and changing the switch, really cant understand where was the problem....maybe some ground conflicts between rca sockets and switch...who knows...anyway now is ok and I will never use hot glue again over a modded console cos messing with wires and solder after having covered everything with glue was a true hell....

thanks for your answer