424 mkii blowing fuses, capstan motor?

[telengard]

I picked up a unit on eBay and it wouldn't power on, replacing the fuses it powers on and the capstan motor spins. However, when I put a tape in and rew/ff the unit powers off and both fuses blow.

I don't have schematics (yet) so I'm just looking for ideas on where to start looking. Is it normal for the motor to always be running? Why is the current draw going so high when rew/ff, enough to blow a fuse? Do I need a new motor?

I also had it blow both fuses while cleaning the pinch roller. I had it against the capstan to get it to spin and I'm not sure if it was due to the slight pressure causing the motor to have to work a little bit, but it happened then as well.

Any insight greatly appreciated!

 

[SkywaveTDR]

There is no magic answer that you seek. The fuses are blowing when a certain function is selected then that function may be making use of a component that is presenting a dead short to the supply. When motors wear badly enough that they cut through and break off a piece of the brush they use for contact to the commutator then that broken off piece can travel around in the motor where it will eventually short causing great current draw. This is not the only possibilities but one of them. A number of experiments will need to be done to see where the cause of the fault lies. This is what a Technician does.

 

[telengard]

Just wanted to post that I figured out what the issue was. One of the little clips that hold the input jacks steady had gotten loose and had fallen beneath one of the boards and was wedged there and was shorting stuff out.

Mystery solved!

 

[SkywaveTDR]

Looking around and use of the ohm meter will get you the same solution even if the clip was not visible. It was an easy fix due to the clop coming off. They usually do not come off by themselves though.