Sony CFS-D7 issue with rewind

[safe1]

Hi guys,

I have just replaced the belts of my Sony CFS-D7 which I acquired some time ago and I realized there is some strange issue with the Rewind function.
When I press the 'REW' button, the deck does a 'FF' (fast forward) instead.
The 'FF' and 'play' operations work as expected (meaning that when I press FF it will fast forward and when I press 'Play" it will play...)
It's only the rewind operation which instead of doing the rewind it does a fast forward.
The supply reel goes counter-clockwise instead of going clockwise (so it would rewind the tape).

Any ideas what to look for?

 

[floyd]

You might want to double-check the routing of the belts.

 

[safe1]

I will double check it tonight and report back. Thank you.

 

[safe1]

So, there was nothing wrong with the routing of the belts. The problem was elsewhere.
In the cassette mechanism there is a part that is called 'FR Idler' (service manual page 9 and 10, description of the STOP, FWD, REW and FF modes).

The position of that 'FR idler' determines which gears is in contact with. In FF mode it engages the take-up spool gear and in REW mode it should engage
the supply spool gear (in the case of the Sony CFS-D7 these are the right and left spools respectively, as you look at the cassette compartment from the front).

Looking at the cassette compartment (while the protection cover plate is removed) the 'FR Idler' needs to move down and left to engage the small white gear
which then engages the supply (left) spool and performs the rewind.
When it is in STOP mode it is in the middle position as it appears in the photo below.
When in FF mode it moves up and right and engages the take-up (right) spool.




Now, my issue was at the back of this 'FR_Idler' mechanism where some black sticky debris in the plastic parts which push the 'FR Idler' 'down and left' -or- 'up and right', was blocking the movement.
My guess is that the sticky debris was leftover from the deteriorated belts which just fell in-between the plastic part that is moving the FR Idler and the FR Idler itself.
When I inspected that spot, the FR Idler was sticking with the other plastic part next to it; I just pushed it softly with my finger and noticed that REW worked.
I have removed the sticky debris and cleaned up the area and since then REW mode is working properly.

Why previously the REW was not working but FF mode was engaged instead?
The answer is simple:
Because when I was pressing the REW button, all the other levers were moving into position for fast forward or rewind except the FR Idler which was staying at the FF position.
So, I was pressing the REW button but the FR Idler was doing FF instead.

Here is the photo of the black sticky debris:




I hope this would be helpful in the future for any other people who might have similar REW ( rewind ) issue with their CFS-D7.
I'm aware of at least one more person who was selling his CFS-D7 in the bay and noted the exact same issue.

Thank you all.