2024-11-24 - Fixing a Sony SLV-E9 VCR
-------------------------------------

A while ago, I got a Sony SLV-E9 VCR with various problems in the
mechanism[0]. Most of the repairs are explained much better in [1]
by 12voltvids (that video is about a different VCR, but the mechanism
is the same). I'll still try to give a general overview of the repairs
I did.

One general note before I forget it: If a VCR behaves weirdly
when the cover is off, it might be because the infrared sensors
are confused. This generally doesn't matter with LED lighting, but
sunlight and incandescent lamps both cause issues.

Power Supply
------------

WARNING: Fixing power supplies is dangerous, please don't kill
yourself. Read up on safely discharging power supply capacitors before
attempting any repairs.

The top cover is held on by four screws on the two sides, but they
were already missing when I got the VCR. When those are unscrewed,
the cover can be removed[2]. I decided to look at the power supply
before even trying to turn the VCR on. There is a small plastic cover
held on by clips that has to be removed before removing the power
supply[3]. There were definitely some bad capacitors in the power
supply (very high ESR), but luckily none had leaked. I still ended up
replacing all of them just in case. I'm not really a fan of replacing
all capacitors when there isn't any reason to, but this VCR is pretty
old and it's annoying to get into the power supply, so it was easier
to just replace them all in one go. I won't go into any details here
since most of the work was just replacing capacitors. The power supply
board is soldered to the metal cage like in the SLV-815[4], but other
than that, it isn't too complicated to replace the capacitors.

Mechanism Disassembly
---------------------

Most of the work I did was on the actual mechanism. To get to the
mechanism, it is necessary to remove the front panel first, which
is held on by plastic clips[5]. Note that there are two clips on the
bottom of the VCR which sometimes require some prying with a flat-head
screwdriver. The front panel is connected to the main board using a
cable bundle. If needed, that can be unplugged from the main board so
the front panel is out of the way. The loading mechanism can then be
removed by unplugging the cables going to the motor and unscrewing
four screws[6][7]. There is a hidden screw that needs to be removed
before the mechanism can be taken out. The circuit board behind the
front panel has a screw on the right and a connector on the left[8]
(yes, I know that the picture was taken before the loading mechanism
was removed). Once those are unscrewed/unplugged, the board can be
flipped down (there are still some clips at the top that need to be
pushed up for that to work). The hidden screw can then be accessed
behind this board[9].

There is a circuit board attached to the bottom of the mechanism, which
in turn is attached to the main board using two connectors that have
to be opened to remove it[10] (note that that picture was taken at the
end, after everything had been fixed). Other than that, there are a few
screws on the borders of the mechanism that need to be removed. There
was also one screw that I removed and then never found again[11],
which is why it's missing in [10]. Note also that an automatic head
cleaner is shown in [11]. I generally always remove those completely
because they eventually get dirty and just end up making everything
worse. I just clean the heads manually when I need to.

WARNING: Do not use Q-Tips or anything similar to clean the heads. The
usual recommendation is to just drench a piece of paper in isopropyl
alcohol, lightly hold it against the head drum, and manually turn the
drum while taking care not to move the paper up or down because that
could break the heads. Please look at a proper guide before you attempt
it yourself, this is just supposed to be a quick warning because many
people have destroyed their heads with improper cleaning techniques.

Once the mechanism has been removed, the circuit board on the bottom
has to be unscrewed. I forgot to take any pictures of it, but it
should be relatively self-explanatory. The main thing to watch out
for is that the infrared sensors for sensing the tape ends are stuck
through small holes in the mechanism, so take care not to snap them
off while pulling the board away.

Note: It is possible to remove the bottom cover of the VCR to get at
the mechanism[35][36], but there are circuit boards in the way.
Considering how annoying it was to get the mechanism out from the top
side, it might still have been easier to just remove those circuit
boards, though.

Stuck Metal Arm
---------------

The first problem with the mechanism was actually on the top side
of the mechanism. A metal arm near the pinch roller was completely
stuck[12]. This problem is also mentioned in [1], although in my case
it was even more severe. I barely managed to open the nut holding it
down. I then cleaned the shaft it was stuck on and the hole in the
arm, and applied new grease. According to the video, you need to
adjust the height once the VCR is in working condition by repeatedly
going into rewind and fast-forward and screwing/unscrewing the nut
until the tape doesn't curl on the top or bottom anymore. In my case,
it seems I managed to screw the nut in to exactly the right height
because I didn't have to adjust it at all later.

Blue and White Gears
--------------------

On the bottom side, the mechanism looks as shown in [13] (note that
this picture was taken after repairing everything). I have also heard
([14]) that the edge of the capstan motor (on the bottom right) is
magnetically coded, so you need to watch out that you don't damage
it either with a magnet or with something hot (like a piece of hot
solder).

The main problem was that the infamous "blue gear" was completely
cracked in half. I didn't take a picture of it, but [15] shows an
intact one (actually, it's the one from the SLV-815 which also had a
small crack in it already, but you can't see it in the picture). You
can still get original blue gears in some places, but I decided to
get a replacement from Van Eck[16]. In order to replace the blue gear,
first the cam gear has to be removed (the large gear at the top left
of [13]), for which the triangular metal piece holding it down has
to be removed. Watch out that you don't lose any of the little metal
rings that are used to hold it down.

The metal arm that the blue gear is attached to can be removed
completely by removing the metal ring fastening it to the tape guide
on the other side[17]. I found it to be the easiest to also remove the
white gear including its metal arm before removing the blue gear. The
new blue gear can then be attached to the metal arm using the spring
inside[18]. This usually isn't very difficult, but the replacement
gear from Van Eck wasn't ideal because the middle part was way too
thick for the hole in the metal arm, so I had to spend ages slowly
grinding away at it until it fit properly. The blue and white gears
need to be aligned properly, as shown in [19] (note that the sliding
gear has also been removed in that picture - it should be possible
to replace the blue gear without doing that, but I had to replace
it anyways, as will be explained shortly). There is an arrow in the
white gear that points at the smaller hole in the blue gear. On the
original blue gear, there is another marking opposite the arrow[15],
but that wasn't included in the replacement from Van Eck.

There was another issue in this area of the mechanism that I only
noticed later. Some plastic had broken off underneath the metal
arm for the white gear[20], causing it to get stuck while loading a
cassette. I cut out small parts from some scrap plastic I had, filed
them down to the correct height, and stuck them on with 2-component
epoxy[21]. It's not perfect, but I greased it properly and it seems
to work fine so far.

Talking about greasing, I've heard various opinions on grease. Many
people swear by Super Lube (also called Synco Lube in Europe),
although there are also different versions of that. I did actually
get some Super Lube, but I don't really like it because it contains
PTFE. Apparently lithium grease attacks plastic, so the gears should
generally be greased with silicone grease, but some silicone grease
is fairly sticky because it doesn't have PTFE or something similar
to make it slippery (now that I think of it, I'm pretty sure I used
some of that sticky silicone grease on the gears around the clutch
assembly in the SLV-815, so maybe it would have worked if I had used a
different type of grease). I eventually started just using the Super
Lube since I had bought that already anyways, and I greased all the
gears that originally had grease on them (but I left the gears that
didn't have any grease on them, so I didn't make the same mistake as
with the SLV-815). However, there are still two different types of
Super Lube, one is the multi-purpose grease, and the other is silicone
grease. I would assume that the silicone grease should be used for
plastic gears, but many people seem to use the regular multi-purpose
grease, so I'm a bit confused. Long story short, I have no idea what
grease is best, and whatever you do, it will probably be wrong anyways.

More Broken Gears
-----------------

Anyways, there were two more broken gears in the mechanism. One was the
gear between the worm gear and cam gear[22] (part number 3-736-015-01),
the other one was the slide gear[23] (3-736-177-01). These proved to
be much more difficult to find than the blue gear. After searching
a lot online, I did manage to find sellers for both, but it ended up
costing much more than the VCR was worth (I'm stupid, so I still went
ahead with it).

To replace the gear between the worm and cam gear, the metal piece
covering part of it has to at least be lifted a bit (it's held on by
gears on the other side of the mechanism, so it's difficult to remove
it completely). One note here is that you also have to remove the gear
that's connected to the capstan motor with a belt (seen best in [13]
at the top right) in order to lift the metal piece. This gear is held
on by both a screw and a spring. The spring is there to help with
putting it back in. If the gear is already at the correct position
but the screw is still loose, the spring pulls it so the belt is at
the correct tension, after which the screw can be screwed down to
fasten it properly.

Alignment and Mode Switch
-------------------------

All the gears have to be aligned properly. This is explained much
more clearly in [1], but I did take a few pictures to show at least
some parts. Most of it is just looking for holes that should line up.
This is all assuming the fully unloaded position where the threading
arms connected to the blue and white gear are fully retracted as
shown in [13]. I already showed the alignment of the blue and white
gears earlier, so I'll only show the remaining parts now. [24] shows
a hole at the right side of the slide gear that should line up with
a hole below. [25] shows how a small rectangular mark in the mode
switch (the gear with the black cover) should match up with the
arrow on the white gear beside it (note that there's also a hole in
the white gear that matches up with the hole shown in [24]). Also
note that the metal ring holding down the white gear is still
missing in [25], don't forget to put that back in.

I also cleaned the mode switch, but I didn't take any pictures of
it. It isn't particularly difficult to open it, you just have to
unscrew the two screws shown in [25] and press the clips in the center
to separate the two parts. I always clean it inside with isopropyl
alcohol (possibly also with a fiberglass pen if it's very oxidized,
although I'm not sure if that's ideal) and then add some dielectric
grease (I read that that's the type of grease you're supposed to
use, but I have no clue what's actually best). The contacts seen
on the outside (at the right in the picture) can also be cleaned
a bit. 12voltvids just uses DeoxIT (which I've never used before)
to clean both the contacts on the inside and outside, but I really
don't know what the ideal method is.

At the same place in the mechanism, but on the top side, the gears
going to the pinch roller need to be aligned[26]. You can see that
each of the shown gears has a hole that aligns with another hole
underneath (or above, in the case of the red gear). The gray gear
also needs to be aligned properly with the tower gear (the tall gear
that guides the pinch roller)[27]. There's a hole in the gray gear
that aligns with a hole below, and also an arrow pointing at a mark
on the tower gear. In order to see this properly, you need to first
remove the cover over the tower gear[28]. [1] mentions that it's a
good idea to clean the shaft the pinch roller is attached to and
grease it as well as the tower gear. If you're careful, you shouldn't
have to fix the alignment here at all, but I accidentally messed it
up, so the tape got caught on the pinch roller on eject until I
properly aligned everything again.

Back on the bottom side of the mechanism, the cam gear has to be
aligned[29]. You can see that there's a hole in the cam gear that lines
up with a hole in the slide gear underneath. There are also three pins
that have to go into the right holes so the cam gear can be pressed
down properly, which can be a bit finicky. One of the pins is moved
by the black plastic piece to the right of the cam gear (as seen in
[13]), which can be helpful to move it a bit while pressing on the
cam gear. Note that this plastic piece often has different colors
in other VCRs, even if they use the same mechanism (in the SLV-815,
it was green).

Once everything is aligned, the triangular metal piece can be attached
above the cam gear again. Don't forget to put in all the metal rings
to hold everything down.

Loading Mechanism
-----------------

I performed one final repair on the loading motor[30]. There is a small
coupling connecting the motor to the worm gear that drives the loading
mechanism. It was still working in this case, but there was already
a crack in it, so I decided to buy a replacement. Van Eck also makes
replacements for this[31]. The side of the mechanism is only held on by
a few clips, so it can easily be removed[32]. The big gear there can be
removed by first removing the metal ring holding it in place, after
which the motor can be unscrewed and the new coupling stuck on[33].
During reassembly, the big gear has to be aligned with two holes in the
metal side, one of which also should be aligned with holes in the other
parts of the loading mechanism, as shown by the screwdriver in [34].

Conclusion
----------

Once all this was finally done, the VCR worked without any
problems. Now I just need to figure out what to do with it because
I have plenty of working VCRs already...


[0] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/slv-e9.jpg
[1] https://youtube.com/watch?v=q-geC1fndSg
[2] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/inside.jpg
[3] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/power_supply_cover.jpg
[4] gopher://lumidify.org/0/phlog/2024-11-24-sony-slv-815.txt
[5] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/front_panel.jpg
[6] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/loading_mechanism.jpg
[7] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/loading_mechanism_removed.jpg
[8] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/front_panel_board.jpg
[9] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/hidden_screw.jpg
[10] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/top_mechanism.jpg
[11] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/missing_screw.jpg
[12] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/stuck_arm.jpg
[13] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/bottom_mechanism.jpg
[14] https://youtube.com/watch?v=xxp_MrsiYhI
[15] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/original_blue_gear.jpg
[16] https://van-eck.net/en/product/sony-left-threading-gear-vhs-slv-xxx-3-736-147-01-373614701-pp-0346/
[17] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/blue_gear.jpg
[18] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/blue_gear_on_arm.jpg
[19] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/blue_gear_alignment.jpg
[20] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/broken_plastic.jpg
[21] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/replacement_plastic.jpg
[22] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/worm_cam_coupling_old.jpg
[23] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/slide_gear_old.jpg
[24] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/slide_gear_alignment.jpg
[25] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/mode_switch_alignment.jpg
[26] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/pinch_roller_alignment.jpg
[27] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/tower_gear_alignment.jpg
[28] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/tower_gear_cover.jpg
[29] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/cam_gear_alignment.jpg
[30] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/loading_motor_coupling.jpg
[31] https://van-eck.net/en/product/motor-pulley-sony-h-mechanism-sony-slv-attached-to-motor-m904-pp-0342/
[32] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/loading_mechanism_open.jpg
[33] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/loading_motor_coupling_replaced.jpg
[34] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/loading_mechanism_alignment.jpg
[35] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/bottom_cover.jpg
[36] gopher://lumidify.org/I/phlog/2024-11-24-sony-slv-e9/bottom_open.jpg