Description
This full erase head has been used in all models since the
SL-C9 onwards. It erases the video, hi-fi
and linear tracks of the tape. It is not used if insert editing is
being used.
It is situated just after the tape exit point from the supply reel
(i.e. before it reaches the complete drum
assembly).
Symptoms
If the full erase head (FEH) is not functioning properly then this can
been seen by patterning moving down the screen for about the first 10
seconds of a new recording (although this can also be due to incorrect
back tension. It is more pronounced when
the new recording is made over an existing recording.
Fixing
This part rarely fails. The more likely cause of the problem is that the
bias oscillator which drives the head is not working. This is usually
due to a broken transformer, drive transistor or capacitor.
Bias oscillator circuit
The head can be cleaned with a little alcohol and a
lint free cloth. Clean the head using a left to right motion not an up and down
one.
This fault is particually common in the
SL-HF950.