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

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?

Reply to
Mike S
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CR got pinned down by the left shuttle assembly during unthreading.

ent that the timing is correct, because all of the holes line up, and the u= 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.)

perly 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 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.

stupid thing still thinks it needs to unthread. The mode switch doesn't u= 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.

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...

Reply to
capnjacksparrowsavvy

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

Reply to
Arfa Daily

got pinned down by the left shuttle assembly during unthreading.

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.)

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.

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.

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

Reply to
Rheilly Phoull

got pinned down by the left shuttle assembly during unthreading.

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.)

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.

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.

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

Reply to
PlainBill

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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...

Reply to
Mike S

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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

Reply to
N_Cook

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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.

Reply to
capnjacksparrowsavvy

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

Reply to
Arfa Daily

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