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01-16-2022, 12:27 PM
amd5 amd5 is offline
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Hi all,

Longtime lurker here. I was recently able to put aside enough funds to start my VHS conversion journey the right way. I reached out to the wonderful lordsmurf and he was able to set me up with a JVC SR-V101 and an AVT-8710 TBC. I already had an ATI AIW 7500 that I acquired a year or so ago which worked great.

I've been playing around with the new gear for about a week and I'm encountering a really strange issue that seems to be related to the TBC. When using either the Composite or the S-Video I/O on the TBC, the picture is full of noise and it looks like periodically part of the frame scans across the screen horizontally. I'm not sure what exactly you would call this behavior in technical terms. I've captured a brief clip of what I'm talking about here: https://streamable.com/55vuln

These are the tests I've done to try and diagnose the problem:

VCR S-Video to AIW S-Video In = OK
VCR Composite to AIW Composite = OK
VCR Composite to TV Composite = OK
VCR S-Video to 8710 S-Video to AIW S-Video In = FAIL
VCR Composite to 8710 Composite to AIW Composite = FAIL
VCR Composite to 8710 Composite to TV Composite = FAIL
VCR S-Video to 8710 S-Video to TV Composite = FAIL (TV doesn't get any input signal at all?)

I've swapped cables out and the issues persist. I had read that the 8710 can be sensitive to "dirty" power, so I tried plugging straight into the wall and plugging in to an APC surge protector, same behavior. One thing I noticed is that the power supply that came with the 8710 is the CUI 12V 500ma. I had stumbled upon a thread that discussed using a 15v 600ma power supply instead? Could this problem be related to the power adapter?

Thanks in advance,
-A
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  #2  
01-16-2022, 12:47 PM
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lordsmurf lordsmurf is offline
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You cannot plug>unplug>plug>etc the AVT-8710. This is exactly what you'll see with that (mis)use. But it's too touchy for that. Other TBCs really are no different here. Plug it in, use it for 6 hours max (AVT-8710 overheats if used too long, 6 hours conservative and safe), unplug it, and let rest for minimum 30 minutes (and longer is better).

It also doesn't play nice with being plugged in while overly cold. Again, that's a lot of electronics. It's winter, you're in Canada, be careful with that.

Do not plug a TBC directly into a wall outlet, ever, period. UPS only, no "surge" strips, etc. TBCs are not consumer electronics, and contain no protections or fuses. If something happens power-wise, it will brick. Whatever happens on the lines will surge directly into the board and fry it.

Also possible, even if unlikely, is the power supply was damaged in shipping. It happens. PSU bricks like the one. These specific 12V CUI negative PSUs may still be cheap on eBay, new, under $15.

The AVT-8710 uses several center-negative PSUs in the 12V-15V range*. That unit was tested with that adapter, and worked very nicely.

Lots of TBCs, like the AVT-8710, are approaching end of life, and need gentle care to keep performing as we need. Any abuse or misuse, and it'll get more finicky or worse.

*
- EverGlow DDU150060 (OEM supplied), 15V 600mA, center-negative
- Kraco 15-06, 15V 0.6A, center-negative
- SP41-150600, 15V 600mA, center-negative
- CUI Stack DPD120050-P5C, 12V 500mA, center-negative
- Jet/ENG 3A-163WP12, 12V 1.25A, center-negative, 100-240V

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  #3  
01-16-2022, 01:14 PM
amd5 amd5 is offline
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Quote:
Originally Posted by lordsmurf View Post
You cannot plug>unplug>plug>etc the AVT-8710. This is exactly what you'll see with that (mis)use. But it's too touchy for that. Other TBCs really are no different here. Plug it in, use it for 6 hours max (AVT-8710 overheats if used too long, 6 hours conservative and safe), unplug it, and let rest for minimum 30 minutes (and longer is better).

It also doesn't play nice with being plugged in while overly cold. Again, that's a lot of electronics. It's winter, you're in Canada, be careful with that.

Do not plug a TBC directly into a wall outlet, ever, period. UPS only, no "surge" strips, etc. TBCs are not consumer electronics, and contain no protections or fuses. If something happens power-wise, it will brick. Whatever happens on the lines will surge directly into the board and fry it.

Also possible, even if unlikely, is the power supply was damaged in shipping. It happens. PSU bricks like the one. These specific 12V CUI negative PSUs may still be cheap on eBay, new, under $15.

The AVT-8710 uses several center-negative PSUs in the 12V-15V range*. That unit was tested with that adapter, and worked very nicely.

Lots of TBCs, like the AVT-8710, are approaching end of life, and need gentle care to keep performing as we need. Any abuse or misuse, and it'll get more finicky or worse.

*
- EverGlow DDU150060 (OEM supplied), 15V 600mA, center-negative
- Kraco 15-06, 15V 0.6A, center-negative
- SP41-150600, 15V 600mA, center-negative
- CUI Stack DPD120050-P5C, 12V 500mA, center-negative
- Jet/ENG 3A-163WP12, 12V 1.25A, center-negative, 100-240V
Thanks for this LS, super helpful. When I first had it plugged in with S-Video cables a few days ago this was the behavior I saw. I just plugged it in (for the first time today) with the composite cables and it works, whereas it did not the past couple of days. I'm going to grab a UPS before I do anything else, and will see if I can dig up some old S-Video gear to test the cables, maybe there's something wrong with them.

I figured as much with the power supply. I knew you tested everything extensively, so I feared the worst.
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  #4  
01-16-2022, 02:16 PM
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VCRs and TBCs can be squirrelly with climates and temps, especially in winter. It really is a The Three Bears scenario. Can't be too cold, nor too hot, must be just right. Sometimes VCRs and TBCs must "warm up".

With the VCR, easy, give it a fodder tape. Some retail test tape you have no problem abusing; I have several. If it messes up the tape, who cares. Just don't ruin the VCR. VCRs may try to eat a tape, but what usually happens is the cold heads start to damage the oxide in flecks. It doesn't shed in the deck, however, not that I've ever seen.

TBCs are more teeth clenching. When you plug in certain TBCs, what you see is scary. This is where experience helps. Some errors, OMG, unplug immediately! Others are fugly video that just needs to hold for warmup. But with the AVT-8710, here's the catch: after a brief warmup of 5-10 minutes, it will need a cooldown for equally 5-10 minutes. Because it doesn't "right itself" right away.

The issue you're seeing is very early stages of needing babying care. By mid/end stages, you won't even see the JVC blue screen or menu, just wavy snow-like psychedelic patterns.

Exception to the rule: Sometimes the TBC needs to be "jostled" back to its senses. In which case, plugging in, and seeing mess, is immediate unplug. And wait at least 30-60 seconds. Try again. And again. It should right itself. But give up if this doesn't do anything after maybe 8 tries. If it starts to get worse, stop immediately.

If you're wondering, no, you won't have to do this every time. Only after long periods of non-use, or after temp/climate changes, like shipping across the country.

It didn't use to be the way. But it's now 15-20 years later for these TBCs. You see this with other models of TBCs. Anybody that says "I never seen it!" will eventually (unless they quit video by then). I guarantee I've seen way, way (way, way, way!) more TBCs than they have. Some are immediately cooperative, some not. It's not quite 50/50 yet, but it's far closer than it was just 3-4 years ago.

On the AVT-8710, the board or chips are damaged when the LED lights are erratic. You're not there. You just have a typical cranky TBC, the electronics version of jet lag, or stiff joints.

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  #5  
01-16-2022, 02:57 PM
timtape timtape is offline
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I bought one of the Ambery model 10 years ago which overall has worked well. Recently it started to show strange symptoms in the picture. Being an electronics tech I opened it up and found two of the ten electrolytic capacitors failed the ESR test. I replaced the two capacitors and now it seems to be working fine again.

After so many years, certain capacitor types fail, in all sorts of electronic equipment. It's a very common situation. Like many techs I've been replacing such faulty caps in a variety of gear since the 1990's. It's just routine work.

Not saying this is your problem but it could be. A competent tech could quickly test these caps for you.

Hope this helps.
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  #6  
01-16-2022, 04:56 PM
RobustReviews RobustReviews is offline
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Quote:
Originally Posted by lordsmurf View Post

Do not plug a TBC directly into a wall outlet, ever, period. UPS only, no "surge" strips, etc. TBCs are not consumer electronics, and contain no protections or fuses. If something happens power-wise, it will brick. Whatever happens on the lines will surge directly into the board and fry it.

Also possible, even if unlikely, is the power supply was damaged in shipping. It happens. PSU bricks like the one. These specific 12V CUI negative PSUs may still be cheap on eBay, new, under $15.

The AVT-8710 uses several center-negative PSUs in the 12V-15V range*. That unit was tested with that adapter, and worked very nicely.
Is this not a SMPS? If it's linear you could run into issues with transients, but frankly, why you would want to use a linear in 2022 is anybody's guess?

If it's an SMPS, it takes care of most transient handling for the vast majority of those encountered, providing it meets a genuine international safety standard?

The US must have very different requirements to Japan/Europe if professional products do not require any sort of over-current protection?
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01-16-2022, 05:44 PM
amd5 amd5 is offline
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Originally Posted by RobustReviews View Post
Is this not a SMPS? If it's linear you could run into issues with transients, but frankly, why you would want to use a linear in 2022 is anybody's guess?

If it's an SMPS, it takes care of most transient handling for the vast majority of those encountered, providing it meets a genuine international safety standard?

The US must have very different requirements to Japan/Europe if professional products do not require any sort of over-current protection?
If the input voltage is any indication, it accepts a fixed voltage of 120V. I know that doesn't necessarily mean it isn't switched, but I don't think I've ever encountered a switched power supply without an input range noted somewhere on it.
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  #8  
01-16-2022, 05:53 PM
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If the input voltage is any indication, it accepts a fixed voltage of 120V. I know that doesn't necessarily mean it isn't switched, but I don't think I've ever encountered a switched power supply without an input range noted somewhere on it.
It'll almost certainly be linear, this poses a greater risk as they're not inherently transient immune, if it's just a transformer and rectifier it'll merrily try and step-up anything passing through it within the bounds of reason. If it's a hefty thing also it's most likely linear.

Switch modes whilst not immune are more likely to a) handle mild transients as they're usually good for 265V-RMS (and no doubt a hefty overhead) by design b) The topology makes them generally fail-open.

It's not to say they're transient immune (that's a specialist area I'm not qualified to speak of), but broadly they'll take a fair bit more abuse than linear, even if they do lunch themselves in the process. Many designs have a crowbar to shunt the input (basically short line & neutral and pop the MCB/fuse in the distribution board) if something goes really wrong, but that will depend on the design.

It's up to you, but I would personally say a UPS is getting a bit too belt and braces for a domestic setting, do you get routine power-spikes? LS seems to have tremendous issues with power so his opinions may well be what he requires.
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  #9  
01-16-2022, 06:25 PM
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Quote:
Originally Posted by timtape View Post
I Being an electronics tech I opened it up and found two of the ten electrolytic capacitors failed the ESR test. I replaced the two capacitors and now it seems to be working fine again.
When it is mere caps, that's great, easy fix. That applies to several TBCs. But it can also be the chips failing, which is unfortunately often the case with the Cypress units. These were not designed overly well, but rather cheaply to their 2x+ cost peers. So for example, not only are heatsinks not present, but there's no room in the case. It'd be a major modification to attempt to heatproof these units. But it's mostly too late now, the damage was done long ago.

Quote:
Originally Posted by RobustReviews View Post
why you would want to use a linear in 2022 is anybody's guess?
2022 doesn't matter. These were designed in Taiwain closer to 2002.

Quote:
The US must have very different requirements to Japan/Europe if professional products do not require any sort of over-current protection?
Japan/Europe has TBCs fail, too. Nothing special about electricity. These components design to be on redundant power sources. Not plugged into the wall at grandma's house, next to the toaster.

Quote:
Originally Posted by RobustReviews View Post
It's up to you, but I would personally say a UPS is getting a bit too belt and braces for a domestic setting, do you get routine power-spikes?
No.

Quote:
LS seems to have tremendous issues with power so his opinions may well be what he requires.
I can only guess you're relatively new to video. Do this for 30 years, and get back to me. Also in multiple locations. Ignore my advice at your own peril. I consider a ~$185 UPS an insurance policy for the $K's of attached gear. (Honestly, if you want to take risks, and have all your expensive equipment bricked by power overage/underage, I don't really care. I'm going to shake my head, and mutter "dumbass". Although it is sad to see some of this gear fail and disappear, so I do actually care for the good of all video users.)

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  #10  
01-16-2022, 08:27 PM
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Originally Posted by lordsmurf View Post
I consider a ~$185 UPS an insurance policy for the $K's of attached gear. (Honestly, if you want to take risks, and have all your expensive equipment bricked by power overage/underage, I don't really care. I'm going to shake my head, and mutter "dumbass". Although it is sad to see some of this gear fail and disappear, so I do actually care for the good of all video users.)
This is the best way to think about it. It would be one thing if this equipment was all still readily available and brand new. If I could go out and buy a TBC for $300, I would likely agree with RobustReviews.

The reality however is much of this stuff has been EOL for at least a decade. I definitely would not have guessed I'd be spending $1000+ on a VCR in 2022. If it costs me an extra $100 or so to ensure this gear lasts me until I'm done my project, so be it.

We don't exactly live in igloos up here in the Great White North, power isn't that big of a concern. That being said winter storms can frequently cause issues with the grid, and I'd rather not have to wait for a clear sunny day to capture some tapes
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01-17-2022, 01:15 AM
timtape timtape is offline
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This is the best way to think about it. It would be one thing if this equipment was all still readily available and brand new. If I could go out and buy a TBC for $300, I would likely agree with RobustReviews.

The reality however is much of this stuff has been EOL for at least a decade. I definitely would not have guessed I'd be spending $1000+ on a VCR in 2022. If it costs me an extra $100 or so to ensure this gear lasts me until I'm done my project, so be it.
A UPS only protects gear against specific electricity supply faults to which that gear is vulnerable. A UPS will not fix already faulty equipment.
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01-17-2022, 12:21 PM
msgohan msgohan is offline
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Does it only do this on the VCR blue screen, or during tape playback too?

You only have either S-Video or composite input plugged in, not both at the same time, right? I ask because I saw picture rolling when I had both inputs connected to my proc amp.
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01-17-2022, 02:45 PM
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Just wanna note about power supplies, working in one place doesn't automatically mean it could not have issues elsewhere due to voltage differences or other things pushing it over the edge (or much less likely something damaged in shipping but that would usually take a lot). I bought a TBC-3000 from LS a few years ago including a PS, the PS worked fine in the US for LS, but when using it here in europe it gave a lot of 50hz noise when plugging it in, and second time I turned it on it died, even though it was supposed to support 230V 50hz according to the labels, so maybe the manufacturer cheaped out or something and didn't actually spec it for 220V. Using my multi-voltage universal supply and later a meanwell PSU works fine however (it still has some high frequency noise on the inputs but not sure if it's related.)

Going from US to Europe voltage is obviously a bigger leap but just wanna note that it could have an impact. You could give it a go with a different, quality PS with the right voltage/pinout and at same or higher (but not like extremely much higher) amperage spec.

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  #14  
01-18-2022, 06:00 AM
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Originally Posted by hodgey View Post
Just wanna note about power supplies, working in one place doesn't automatically mean it could not have issues elsewhere due to voltage differences or other things pushing it over the edge (or much less likely something damaged in shipping but that would usually take a lot). I bought a TBC-3000 from LS a few years ago including a PS, the PS worked fine in the US for LS, but when using it here in europe it gave a lot of 50hz noise when plugging it in, and second time I turned it on it died, even though it was supposed to support 230V 50hz according to the labels, so maybe the manufacturer cheaped out or something and didn't actually spec it for 220V. Using my multi-voltage universal supply and later a meanwell PSU works fine however (it still has some high frequency noise on the inputs but not sure if it's related.)

Going from US to Europe voltage is obviously a bigger leap but just wanna note that it could have an impact. You could give it a go with a different, quality PS with the right voltage/pinout and at same or higher (but not like extremely much higher) amperage spec.
SMPS by design are fairly input agnostic, all the 'clever' stuff is being done in the high-frequency stage, the AC is being rectified and switched, so within the bounds of component design and rectifier specification they aren't especially bothered about the input voltage/frequency, you can even use many designs as DC-DC converters too, they simply don't care within worldwide LV bounds.

I imagine in your case it was either, as you describe, an incredibly low-quality unit with unsuitable components or probably more likely, tired components that simply 'let the magic smoke out' when given a more thorough workout, reformed capacitors etc. Because they require X/Y capacitor arrangements component selection is vital, also if they have a MOV (metal oxide varistor) and had been routinely 'spiked' it could also have been weak and shorted itself. 50Hz noise super-imposing onto the DC output is a clear indicator that a capacitor had failed or that the rectifier wasn't up to the task.

Because we're playing with high-frequency, 'high-current' switching they spew broadband RF and electrical noise unless they're very carefully designed and shielded, so they're always a great place to look for electrical noise issues. Linears don't do this very appreciably, however, they're heavy, inefficient and get toasty warm as linear regulation has to 'dump' the unwanted voltage component through a resistor. That's not eco-friendly, generates its own problems with heat and foreshortening of component life.

That's why I'd really want to know what the regulator inside the unit is between randomly switching between a 12VDC and a 15VDC source, one or both of those is incorrect both providing the units are identical. It's trivial to open the unit and check coupled with a quick burst of mental arithmetic. Excessive voltage is going to drive the unit's DC linear regulation to dissipate a lot of heat, too low and you're potentially in the dropout area of the component behaviour.

There are also questions for those of us in commercial properties billed in Volt-Amps rather than Watts, but that's a whole other topic of no relevance here.

Last edited by RobustReviews; 01-18-2022 at 06:22 AM.
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