Sony EVS9000E tape riding over pinch roller in Fast Forward

[Colin McCormick]

Does anyone have experience with the Sony EVS9000E? This is a
very elaborate Hi8 edit deck. The deck is completely different
to the EVS1000, EVSC3 etc.

Original fault: A split in the supply spool teeth. I've seen
this before and replaced the supply spool. This does involve
removing the back tension band, I carefully marked its position
and refitted in the same position exactly.

The machine worked but would occasionally damage a tape in
play or F-Fwd. The tape could be seen to ride up over the
top of the pinch roller.

At great expense I replaced the pinch roller. This made the
situation better, but still sometimes the tape will ride
over the top of the pinch roller in Fast Forward. It can
take the tape right off the pinch roller and head exit
guide, and it then sits in an illegal position bypassing
both of these. Ejecting from this condition would of course
wreck the tape.

I have noticed when in Fast-forward that the tape sometimes
moves in a slightly less than smooth fashion, and it may
be this which is allowing the tape to get too high on the
guides and then go of the top.

In case I had set the back tension somehow too high, I
slackened this off by the tiniest fraction of a mm, but the
problem persists.

If anyone is familiar with this mechanism, please contact me
on [email protected]

Many thanks for any help.

Colin

 

[Colin McCormick]

Further to this, a video clip of the problem
can be seen here:
http://www.colin99.co.uk/extras/hi8_fault.mpg
3MB size, MPEG2 file.

Colin

 

[Andy Cuffe]

Further to this, a video clip of the problem
can be seen here:
http://www.colin99.co.uk/extras/hi8_fault.mpg
3MB size, MPEG2 file.

Colin

Insufficient torque on the take up reel can cause this type of
problem. I've seen a lot of VCRs (although not this one) where the
slip clutch becomes too loose. Incorrect back tension is another
possibility (try a slight increase in back tension). Have you
confirmed that its alignment is ok?
Andy Cuffe

[email protected]

 

[Colin McCormick]

Andy

I had independantly located the problem. Yes, it was
insufficient back tension. When replacing the supply
spool, I had tried to put the back tension band back
in exactly the same loaction but was a fraction of a
mm out.

My word 8mm is sensitive to back tension! Much more
so than Beta.

Thanks for your help, you've confirmed my diagnosis.

Regards,

Colin

www.video99.co.uk