Help with Yamaha mt120 4-track

[Hithanksbye]

I bought an old Yamaha Mt120 - the guy said it was in working order except tracks 2 and 4 were quieter on recording . That didn’t matter to me since only want to use it to digitize a bunch of old band tapes. I just received it yesterday and in my excitement I popped in a tape that is probably 20 years old. It worked decently for a few minutes (although it sounded pretty scratchy, I figured it was just the tape), but then when I popped in a different tape the thing started freaking out! It started playing at fast forward speed, then it would rewind and fast forward on its own, the play head going up and down on its own. Basically it seems possessed... I’m capable of taking things apart and replacing physical parts so I’m hoping it’s something mechanical. This 4-track has soft buttons so I’m hoping it’s not something like a processor or something that I can’t figure out. Any ideas? Also, if it’s something mechanical where do y’all pick up these old parts? Thanks in advance.

 

[pd2606]

I had one of these exact 4 tracks back in the 90's. Great little units in the day - unfortunately mine was lost/stolen, who knows ....anyway 20 years later I decided I wanted it back to listen back and transfer old demo tapes to DAW, so bought one off Ebay, (hard to find) needs some TLC & now in the process of trouble shooting a few issues such as track level meters not working & tracks 1 & 2 not loud enough etc etc...fun & games
anyhoo I digress....
In the course of hunting around for possible fixes I came across this clip which I reckon pretty much describes your problem - its to do with the cam gear cog not being in the correct position. It could be as simple as flicking it around to the correct position.
Good luck

 

[seankerns]

I had a Tascam 424 back in the early 90's. My first multitrack recorder. Traded it about 20 years ago for a guitar, after it sat for several years. I had recorded some stuff on it that I wanted to listen to again, so I found another. Actually a 424 Mk III.
The problem? I can't figure out where I put the tapes.

 

[bungler666]

Not sure about the transport problem but the low recording level on 2 and 4 is probably due to bad caps, had the same problem on mine. I’d say recap the entire mixer board.