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

[Mike S]

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 confident 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.)

However, I cannot get system control to understand that the system is 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.

I've tried disconnecting the unit from power for hours at a time, and the 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.

Does anyone have any ideas how to approach fixing this?

[capnjacksp...@gmail.com]

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 across the country, and I'd have to blindly send in the unit with a form and pray 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 mention that I'm probably looking at $270 bare minimum to flash the firmware (apparently it takes two hours?!?), plus $80 shipping or so total, but their standard operating procedure is to bring every machine back up to factory specs entirely, so who knows how much it would really cost? I can just imagine someone taking ten minutes for every variable resistor, making minute adjustments 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 sure 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 it 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. Otherwise, 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...

[Arfa Daily]

"Mike S" <capnjacksp...@gmail.com> wrote in message
news:14063834.146.1334859505608.JavaMail.geo-discussion-forums@ynnf1...

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

[Rheilly Phoull]

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

[Plai...@yawhoo.com]

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

[Mike S]

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...

[capnjacksp...@gmail.com]

On Friday, April 20, 2012 6:38:02 AM UTC-4, Rheilly Phoull wrote:
>
> Could be mebbe you should be thinking about coming up into the 20'th
> century and going DVD ??

If you're talking about ditching commercial VHS movies and picking up the $4.99 DVD versions at Wal-Mart, well, no, that's not exactly an option for me. I'm in the process of digitizing my family's home movies actually, and the SVO-5800 is the best playback deck I've found for my tapes (since my camcorder movies are almost all SP mode).

I'll be dubbing to DVD, but not directly, since it's going to be just as dead as VHS in due time. Instead, I'm going with lossless PC capture FTW, followed by extremely high bitrate H.264 permanent archive encodes with x264, followed by however much Avisynth filtering I want, followed by distribution encodes for family on DVD and smaller H.264 encodes for casual viewing on the computer. Yeah, I'm serious about this stuff. :p

In other words, I'm dealing with VHS for now because I must, not because I'm a masochist or something.

[N_Cook]

Mike S <capnjacksp...@gmail.com> wrote in message

news:28083887.1110.1334963952805.JavaMail.geo-discussion-forums@ynlp3...

++++++

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

[capnjacksp...@gmail.com]

On Saturday, April 21, 2012 6:33:00 AM UTC-4, N_Cook wrote:
>
> ++++++
>
> 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

Unfortunately, operating with the covers on still didn't work. It was a good idea though, given the optical mode switch.

The optical top/end sensors don't seem to be playing into this either: Blanking 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 activated), and even setting the appropriate dip switch to ignore them doesn't affect the issue. Plus, an active tape top or end sensor shouldn't result in eternal unthreading anyway, since a successfully unthreaded machine - even with a tape in it - might still see light with one of the sensors if the tape is really at the top or end.

[Arfa Daily]

"Mike S" <capnjacksp...@gmail.com> wrote in message

news:28083887.1110.1334963952805.JavaMail.geo-discussion-forums@ynlp3...

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