hifi engine

TEAC A3440 4 track reel to reel

I have an original A3440 wonderful piece of hardware that is now over 30 yrs old and until 2 days ago was still running fine., but then the transport controls (FF/REW/Play) etc stopped working and no action from mechanism. they "clikc" but no relays or hardware responds.

I do have the manauls for this legend but its gonna take me a while to fathom so was wondering if someone with past experience would know what causes this? (most likely its a dead relay me thinks, but a pointer about that would be great)