Sony SVO-5800 Eternally Tries to Unthread, Then Errors Out (Gears Perfectly Timed)

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Hey guys,
I posted here recently about a problem where the back tension arm on my VCR=
 got pinned down by the left shuttle assembly during unthreading.

I've fixed that issue, and I've retimed all the gears.  I'm pretty confiden=
t that the timing is correct, because all of the holes line up, and the uni=
t can be easily threaded and unthreaded manually by turning the worm wheel.=
  Everything seems to move as it should, when it should.  (There's a possib=
le exception with my right shuttle:  It could possibly be off by one tooth,=
 since the gear looks slightly different from what the service manual shows=
, and the arrows are unhelpful.  However, moving this gear a tooth in eithe=
r direction does not affect my current issue, and it's in the middle positi=
on of only three that allow the shuttle to easily move all the way to both =
ends of the VCR.)

However, I cannot get system control to understand that the system is prope=
rly unthreaded.  Whenever I turn the power on, it tries to unthread.  If I =
start the gears out unthreaded, the motor will encounter resistance, and th=
e machine will error out.  If I start the gears out threaded, it will unthr=
ead, keep trying to go farther, encounter resistance, and error out.  If I =
disconnect the motor from the gears, it will time out, then error out.  It'=
s always the same error, 09-821, which indicates the system could not unthr=
ead in the specified time.

I've tried disconnecting the unit from power for hours at a time, and the s=
tupid thing still thinks it needs to unthread.  The mode switch doesn't use=
 any levers or moving parts:  It bounces light off of reflective tracks on =
the back of the mode gear, which is perfectly timed with the rest of the pa=
rts.

Does anyone have any ideas how to approach fixing this?

Re: Sony SVO-5800 Eternally Tries to Unthread, Then Errors Out (Gears Perfectly Timed)
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nit can be easily threaded and unthreaded manually by turning the worm whee=
l.  Everything seems to move as it should, when it should.  (There's a poss=
ible exception with my right shuttle:  It could possibly be off by one toot=
h, since the gear looks slightly different from what the service manual sho=
ws, and the arrows are unhelpful.  However, moving this gear a tooth in eit=
her direction does not affect my current issue, and it's in the middle posi=
tion of only three that allow the shuttle to easily move all the way to bot=
h ends of the VCR.)
Quoted text here. Click to load it
I start the gears out unthreaded, the motor will encounter resistance, and =
the machine will error out.  If I start the gears out threaded, it will unt=
hread, keep trying to go farther, encounter resistance, and error out.  If =
I disconnect the motor from the gears, it will time out, then error out.  I=
t's always the same error, 09-821, which indicates the system could not unt=
hread in the specified time.
Quoted text here. Click to load it
se any levers or moving parts:  It bounces light off of reflective tracks o=
n the back of the mode gear, which is perfectly timed with the rest of the =
parts.
Quoted text here. Click to load it

Oh, man.  I called up Sony, and the tech seems to think I need the firmware=
 reflashed.  Only one Sony servicing center does it, it's all the way acros=
s the country, and I'd have to blindly send in the unit with a form and pra=
y the estimate is going to be reasonable.  If it's not, it's a $135 charge =
plus ~$40 shipping each way just to get my broken deck back.

After some badgering, I finally got one of their tight-lipped reps to menti=
on that I'm probably looking at $270 bare minimum to flash the firmware (ap=
parently it takes two hours?!?), plus $80 shipping or so total, but their s=
tandard operating procedure is to bring every machine back up to factory sp=
ecs entirely, so who knows how much it would really cost?  I can just imagi=
ne someone taking ten minutes for every variable resistor, making minute ad=
justments with an oscilloscope...

Jeez.  Couldn't they just sell me a fresh EE-PROM or chip or whatever kind =
of chip I need for $10, and I can solder the dang thing on myself?  I'm sur=
e I'll have it repaired someday (it's technically worth it), but right now =
all I can afford is to gamble on a fresh replacement.

If anyone else has any other ideas besides "flash the firmware by sending i=
t to an expensive repair center thousands of miles away," let me know. :)  =
I'd love to find out that this problem can be resolved in a cheaper way.  O=
therwise, my best idea at the moment is to get a totally busted "for parts"=
 deck and swap out the board with the firmware...since I'm pretty sure the =
system control firmware is on the SS-58 board...

Re: Sony SVO-5800 Eternally Tries to Unthread, Then Errors Out (Gears Perfectly Timed)


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Have you tried it with the covers back in place ? Many VCRs do the oddest
things when bench light gets into the optical deck sensors. I don't think
that I have ever come across a deck that has an optical mode switch, but if
light got into that, I can imagine it would wreak havoc with the system
control. I'm trying to remember exactly what you said in your original post,
without going to look, but I think that it was all basically working except
for a fairly minor problem with the left loading arm nor withdrawing at the
correct time. If this was the case, and its now doing this new behaviour
after you realigned it, then the conclusion has to be that it is not aligned
correctly, no matter how much it looks like it is. I've been doing bench
work on equipment like this, for 40 years, as have many others on here, and
I think that we would all tell you from our own experience, that when a
fault 'changes' (usually for the worse like in your case)  after you have
carried out some repair procedure, then the most likely cause is that you
have done something wrong yourself. I'm not specifically familiar with this
model, but if it's like most VCRs which use a conventional mechanical mode
switch, the timing of that switch relative to the rest of the mech is
absolutely critical, and completely unforgiving of being even a part tooth
out, let alone a whole tooth or more.

Arfa


Re: Sony SVO-5800 Eternally Tries to Unthread, Then Errors Out (Gears Perfectly Timed)
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Thanks for your insightful post!  The mode switch is optical, but the PCB c=
ontaining the optical sensors covers that side of the mode gear almost enti=
rely.  However, two holes are left open for alignment purposes, and some li=
ght might be escaping into the space between the gear and the sensors from =
there.  You made an extremely good point about that, and I will try again w=
ith the bottom cover on (since I haven't had that one on for a while).

If that's not the issue though, a firmware issue sadly doesn't sound too un=
likely:  The deck was power cycled God-knows-how-many times in its unfixed/=
half-fixed state, and I wonder if something about that may have gotten syst=
em control to enter some kind of infinite loop of sorts.  Either that, or I=
 might have accidentally damaged the electronic circuits around the mode sw=
itch (such as the sensors) with a static discharge in the process of contin=
ually messing around in that area.

I don't think it even can be a gear timing issue at this point:  Even when =
I deliberately moved the gears significantly out of time so the deck could =
move them as far as possible in the direction it's trying to move them, sys=
tem control still wanted to go further.  I think the deck determines the st=
ate based on the position of the mode gear (and errors out if the cam motor=
 encounters resistance along the way), so it should theoretically stop the =
cam motor and assume it reached its desired state once the mode gear advanc=
es to the point it needs to.  However, it behaves such that no possible pos=
ition of the mode gear will ever successfully convince the deck that it's u=
nthreaded...which may very well suggest you're onto something about light m=
essing it up.  I can't BELIEVE I didn't think of that...

Re: Sony SVO-5800 Eternally Tries to Unthread, Then Errors Out (GearsPerfectly Timed)
Quoted text here. Click to load it
the
be
this
easily
unthread.
resistance,
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system
the
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post,
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and
this

Thanks for your insightful post!  The mode switch is optical, but the PCB
containing the optical sensors covers that side of the mode gear almost
entirely.  However, two holes are left open for alignment purposes, and some
light might be escaping into the space between the gear and the sensors from
there.  You made an extremely good point about that, and I will try again
with the bottom cover on (since I haven't had that one on for a while).

If that's not the issue though, a firmware issue sadly doesn't sound too
unlikely:  The deck was power cycled God-knows-how-many times in its
unfixed/half-fixed state, and I wonder if something about that may have
gotten system control to enter some kind of infinite loop of sorts.  Either
that, or I might have accidentally damaged the electronic circuits around
the mode switch (such as the sensors) with a static discharge in the process
of continually messing around in that area.

I don't think it even can be a gear timing issue at this point:  Even when I
deliberately moved the gears significantly out of time so the deck could
move them as far as possible in the direction it's trying to move them,
system control still wanted to go further.  I think the deck determines the
state based on the position of the mode gear (and errors out if the cam
motor encounters resistance along the way), so it should theoretically stop
the cam motor and assume it reached its desired state once the mode gear
advances to the point it needs to.  However, it behaves such that no
possible position of the mode gear will ever successfully convince the deck
that it's unthreaded...which may very well suggest you're onto something
about light messing it up.  I can't BELIEVE I didn't think of that...


++++++

The optical end of tape sensor system , both sides, that needs to be blanked
off or m/c tested (without top cover) in a low light level room



Re: Sony SVO-5800 Eternally Tries to Unthread, Then Errors Out (GearsPerfectly Timed)
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Unfortunately, operating with the covers on still didn't work.  It was a go=
od idea though, given the optical mode switch.

The optical top/end sensors don't seem to be playing into this either:  Bla=
nking them out, taping over them, and/or putting on the covers successfully=
 keeps light from them (I can check in the menu whether they're being activ=
ated), and even setting the appropriate dip switch to ignore them doesn't a=
ffect the issue.  Plus, an active tape top or end sensor shouldn't result i=
n eternal unthreading anyway, since a successfully unthreaded machine - eve=
n with a tape in it - might still see light with one of the sensors if the =
tape is really at the top or end.


Re: Sony SVO-5800 Eternally Tries to Unthread, Then Errors Out (Gears Perfectly Timed)


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Another thing that you might try is to remove one of the gears far down the
chain, to effectively disconnect the bit that's jamming - presumably the
loading arms as they are fully retracted - if that's possible on this mech,
to allow the loading motor to run just the mode switch and any other gears
that may be involved. That will allow you to see if it can in fact ever find
a position where it will stop. If you can find such a position, looking at
where the gears are then, may give a clue as to why the thing tries to run
on as it's currently aligned, and how it should be aligned to achieve that
condition with the whole gear chain in place.

If it's not anything to do with light getting into the mode switch, then my
money would still be on it being an alignment issue. Some of these mechs can
be barstorial things to get right, even with a diagram. One that comes to
mind is the Panasonic CD stacking  multichanger that they fitted to a number
of their compact hifis. Even with the complete alignment instructions, which
are available in full colour as a manual supplement, and run to 20 odd pages
as I recall, it is still almost impossible to get them right to the point
where they will run faultlessly and repeatedly.

Arfa


Re: Sony SVO-5800 Eternally Tries to Unthread, Then Errors Out (Gears Perfectly Timed)
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got pinned down by the left shuttle assembly during unthreading.
Quoted text here. Click to load it
that the timing is correct, because all of the holes line up, and the unit can
be easily threaded and unthreaded manually by turning the worm wheel.
Everything seems to move as it should, when it should.  (There's a possible
exception with my right shuttle:  It could possibly be off by one tooth, since
the gear looks slightly different from what the service manual shows, and the
arrows are unhelpful.  However, moving this gear a tooth in either direction
does not affect my current issue, and it's in the middle position of only three
that allow the shuttle to easily move all the way to both ends of the VCR.)
Quoted text here. Click to load it
unthreaded.  Whenever I turn the power on, it tries to unthread.  If I start the
gears out unthreaded, the motor will encounter resistance, and the machine will
error out.  If I start the gears out threaded, it will unthread, keep trying to
go farther, encounter resistance, and error out.  If I disconnect the motor from
the gears, it will time out, then error out.  It's always the same error,
09-821, which indicates the system could not unthread in the specified time.
Quoted text here. Click to load it
stupid thing still thinks it needs to unthread.  The mode switch doesn't use any
levers or moving parts:  It bounces light off of reflective tracks on the back
of the mode gear, which is perfectly timed with the rest of the parts.
Quoted text here. Click to load it

Could be mebbe you should be thinking about coming up into the 20'th
century and going DVD ??


Re: Sony SVO-5800 Eternally Tries to Unthread, Then Errors Out (Gears Perfectly Timed)
On Fri, 20 Apr 2012 18:38:02 +0800, Rheilly Phoull

Quoted text here. Click to load it
got pinned down by the left shuttle assembly during unthreading.
Quoted text here. Click to load it
that the timing is correct, because all of the holes line up, and the unit can
be easily threaded and unthreaded manually by turning the worm wheel.
Everything seems to move as it should, when it should.  (There's a possible
exception with my right shuttle:  It could possibly be off by one tooth, since
the gear looks slightly different from what the service manual shows, and the
arrows are unhelpful.  However, moving this gear a tooth in either direction
does not affect my current issue, and it's in the middle position of only three
that allow the shuttle to easily move all the way to both ends of the VCR.)
Quoted text here. Click to load it
properly unthreaded.  Whenever I turn the power on, it tries to unthread.  If I
start the gears out unthreaded, the motor will encounter resistance, and the
machine will error out.  If I start the gears out threaded, it will unthread,
keep trying to go farther, encounter resistance, and error out.  If I disconnect
the motor from the gears, it will time out, then error out.  It's always the
same error, 09-821, which indicates the system could not unthread in the
specified time.
Quoted text here. Click to load it
stupid thing still thinks it needs to unthread.  The mode switch doesn't use any
levers or moving parts:  It bounces light off of reflective tracks on the back
of the mode gear, which is perfectly timed with the rest of the parts.
Quoted text here. Click to load it
Could it be that you should try NOT to live up to your name?  

From Sony's description of the SVO-8500:
"Combining a host of advanced features and outstanding value, the
SVO5800 is a powerful tool that will complement any professional
editing environment, from a basic two-machine editing system to a
sophisticated A/B roll editing suite.This professional S-VHS editing
recorder/player is the result of Sony's accumulated experience and
commitment to the development of editing recorders. The SVO5800 model
offers all the convenient operating features required for professional
editing in the S-VHS format: frame accurate assemble/insert editing,
built-in time base corrector, built-in LTC/VITC time code
generator/reader and user-friendly menu operation. An RS-422A
interface port is also provided for versatile editing system expansion
and flexible system control. The optional Component Out capability
allows easy integration into Betacam SP-based editing systems."

PlainBill

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