"bg" wrote in message
...
The heads from left to right are, the erase head, the record head and the
playback head. Any cassette I've ever seen has a guide attached to the
playback head.
The guide attached to the PB head is fine. It is the one on the Rec head
that is bent. It is ruined. It was affixed to the R-head with a screw and
enamel. It came loose and is impossible to align. The head must be removed
to tighten the screw and adjustment is not possible when head is remounted.
The deck appears to be technology without due design consideration.
If possible, bend the damaged guide back into place. Usually
this guide is spot welded, therefore the height of the guide might not
have
changed. This guide sets the tracking which usually is not adjustable
because the guide is fixed to the playback head at the factory. On rare
occasions this guide is adjustable.
The tilt of the head sets azimuth which is adjustable on all decks.
As with every other deck i have seen, which are all single motor low end
decks, only the azimuth is adjustable with the typical screw and spring set
up.
You will
have to examine the record and playback heads to see if there is azimuth
adjustments for both heads.
yes, there is also azimuth for the record head
I would expect there is. Head height raises or
lowers the position of the head gaps on the tape.
I will look again to see if there is a height adj
Azimuth rotates the gaps
so that they are aligned perpendicular (90 degrees) to the tape.
I understand
Azimuth
will have a slight effect on the head height. Another head adjustment you
might have is zenith. Usually located at the rear of the head, it tilts
the
face of the head, so that the head is parallel to the tape.
I'll check, I have never noticed this
This adjustment
if incorrect, would tilt the top of the head either closer or further from
the tape than the bottom of the head. It causes uneven head wear and it
causes the tape to scew up and down. As the tape scews, the azimuth and
tracking will also be out of adjustment. The erase head should also have a
non adjustable guide affixed to it.
Yes, it does
Check to see that you have these guides in place, the azimuth and zenith
adjustments, and that the adjustments will move the heads.
It looks to me that the zenith is set with the azimuth screw. There is some
travel in the slot that allows rotation of the head.
If you can't
physically align the heads, or the guides are bad, there is no sense in
going any further. you will have to replace whatever mechanics are bad.
You might want to sacrafice an old cassette by cutting away the plastic
shell in the area where the heads contact the tape. This will give you the
abiltiy to see how the tape rides over the heads.
I will look into it
If the tape is visibly
moving up or down, you will have to correct this. It is impossible to
align
a head to tape that moves all over the place. The basic concept is to set
all guides at the same height so that the tape enters the shell and
leaves
the shell at the same height.
Makes sense
Any guides in between should not raise or
lower the tape as it travels thru the shell.
Post back here with your results and we'll determine the next step.
Thanks BG. I have several projects like this. This one will have to sit
awhile until its' time comes. I wanted to look into it now so I could plan
what to do.
If you will send me your e-mail address to
I will get back to
you when I get these other projects out of the way.
Sincerely, Mark
bg
Marko wrote in message ...
BG: I thought I would check for replies just one more time before I
stopped
NG activity for awhile. Glad I did.
I have a signal generator, alignment tape, scope, and HP5210 freq meter
that
I have used to set the motor RPM with 1KHz test tone.
I haven't checked yet, but I am hoping that
(1) the head on the far right is the play head
(2) the tape monitor switch will allow me to record a test tone (I will
use
10KHz) and then monitor it with the play head so that I can align the
record
head.
(3) that the tape guide on the PB head (which has been bent out of the
tape
path) is not necessary for proper tape transfer over the heads.
What worries me is that the tape guide is on the record head and I must
align the playback head first.
I didn't notice the third head at first and aligned the playback with the
record head adjustment screw. This worked because the tape guide is on
the
record head.
How do I start out with proper alignment of the two tape guides before
aligning the heads? One guide, the first one, is affixed to the
transport
frame and the second guide is affixed to the record head. I think this
problem may have been encountered by
whoever worked on it before it was sent to a resale shop. I could see
that
they had disturbed the paint on the screws. It also had two stretched
belts
and a very dirty rec/play switch on the board, so I'm not sure. The
belts
may have stretched and the grease in the switch may have dried from
sitting
on the shelf for years after they encountered the alignment problem.
What do you suggest? Sincerely, Mark (this is a top post)
----- Original Message -----
From: "bg"
Newsgroups: sci.electronics.repair
Sent: Sunday, July 27, 2003 11:46 PM
Subject: Fisher cassette heads
You need an audio generator, and an AC audio voltmeter with a DB
scale.
If
you have this equipment I'll steer you through it.
bg
Marko wrote in message ...
I have a Fisher cassette deck with separate record and playback heads.
I
assume that the one in the middle, the large one, is the record head.
I have a professional alignment tape. How does one align the record
head?
There is a tape monitor switch which probably is used to compare input
to
output.
These are ferrite heads with no visible wear, new belts, switches
cleaned
thoroughly: this deck is worth an alignment as opposed to the trash
can
(mabey).
Also, one tape guide (the one on the far left, just to the left of the
record head) is affixed to the transport frame. The second guide is
affixed
to the record head. The third tape guide on the playback head is bent
over
to the side, obviously bent intentionally to get it out of the way.
The
adjustment screw to this bent guide is not accessable for adjustment
(sloppy
design). The third tape guide is probably not necessary since it is
only
about a cm from the guide on the record head. This transport may be a
piece
of junk due to lousy design.
Any helpful hints will be appreciated Thanks, Mark
"bg" wrote in message
...
You need an audio generator, and an AC audio voltmeter with a DB
scale.
If
you have this equipment I'll steer you through it.
bg
Marko wrote in message ...
I have a Fisher cassette deck with separate record and playback heads.
I
assume that the one in the middle, the large one, is the record head.
I have a professional alignment tape. How does one align the record
head?
There is a tape monitor switch which probably is used to compare input
to
output.
These are ferrite heads with no visible wear, new belts, switches
cleaned
thoroughly: this deck is worth an alignment as opposed to the trash
can
(mabey).
Also, one tape guide (the one on the far left, just to the left of the
record head) is affixed to the transport frame. The second guide is
affixed
to the record head. The third tape guide on the playback head is bent
over
to the side, obviously bent intentionally to get it out of the way.
The
adjustment screw to this bent guide is not accessable for adjustment
(sloppy
design). The third tape guide is probably not necessary since it is
only
about a cm from the guide on the record head. This transport may be a
piece
of junk due to lousy design.
Any helpful hints will be appreciated Thanks, Mark