424 mkII: high frequency noise on channel 4 when playing back

Discussion in 'TASCAM Analog Forum' started by FM Towns, Jul 18, 2014.

  1. FM Towns

    FM Towns New Member

    Jul 2014
    Portastudio 424 MKII
    when I play back tapes on my 424, i've noticed a bit of noise coming from channel 4 when playing back, even when I trick the deck into thinking it has a tape. It is very distinguishable from tape hiss, it sounds more like frequent high frequency pops rather than a constant hiss. one thing i have noticed is that the noise is reduced when i change it to the higher speed, and is (almost) completely masked when noise reduction is on.

    what would be the cause of this? could it be a bad solder joint somewhere or do I just need to demagnetize the heads? any help would be appreciated, I would like to know if it's something i could take care of myself with my minimal amount of electronics experience. thank you, hopefully we can get this figured out <3