Quantcast Color Loss when turning on TBC on JVC 7600EU VCR ? - digitalFAQ Forum
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  #1  
10-05-2012, 04:57 AM
pete pete is offline
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Hi All

Basic setup windows xp pentium 4 1.5 ghz ram ati aiw 9600 card
JVC hrs 7600 EU
capturing to mpeg old vhs tapes


A strange problem is occurring when i engage the tbc on my jvc vcr , the moment i turn it on the color disappears from the picture , turn it off , color comes back . I can see the tbc makes the picture more stable , but obviously i need the color in the picture. Any ideas why this is happening ?
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  #2  
10-05-2012, 05:27 AM
juhok juhok is offline
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Does this happen if you plug 7600 to TV?
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  #3  
10-05-2012, 05:51 AM
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i dont really have the cables to plug into my tv , as as far as i can tell i only have svideo out on back of vcr , well scart as well , and my tv only takes composite , vga , hdmi , it doesnt take svideo . So i dont really have a way of testing that right now. What would that indicate if it did or didnt
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10-05-2012, 05:53 AM
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If it's bw with TV also, something seriously wrong with the unit.
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  #5  
10-05-2012, 05:55 AM
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1. Do not use any converter cables -- i.e., composite to s-video, SCART to s-video, etc. That often causes chroma channels to be dropped, and thus gives a B&W signal. Even cheap cables, or too-long cables, can be a problem.

2. You must find a way to test this on a TV set, to eliminate the capture workflow as the source of the problem. If not your TV, then find another TV somewhere that takes s-video or SCART. Surely you have friends or family with an older tube in the garage, kitchen, spare/guest bedroom, etc?

3. There is a chance that the TBC is simply defective, but it's not as likely as other issues to do with wiring (wire quality), lack of an external TBC between the VCR and capture card, or several other potential reasons. Testing it into a TV is the first step, however.

4. Also test with more than one tape, to eliminate the tape as the problem.

Then report back.

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  #6  
10-05-2012, 06:15 AM
pete pete is offline
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Okay , ill have to hund around as svideo was never very common in South Africa Some additional info. At this stage i dont have an external tbc running in my system , Also i popped another tape into the system and it initially did the same thing , but then it also dropped the color on normal mode as well and was playing in B&W

After that i popped the original back in , it has color without tbc on !!! and then loses color with tbc off .
then i put another tape in and it plays color no problem with tbc on ?
So wow there are serious variations going on .
Does this comparison help with refining my first step

from watching the tape that works with color when tbc is on and off some more , it does seem that the tbc causes the picture to lose color at isolated moments at times when the tbc is on , where as the color is more stable with the tbc off .

I am interested to know if that means the tbc is playing some role in influencing the color
Would an external tbc perhaps make the signal more resistant to this ?

Just to add one more tape to the mix , i tried a commercial vhs cassette with an old sports highlights package i had purchased and it had completely stable color with tbc on
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  #7  
10-05-2012, 07:01 AM
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It could still be due to the capture workflow. You need to eliminate it by direct TV testing. There's really no way to avoid it. Any output into a TV would work.

I have experience with chroma disappearing on a JVC deck. In that instance, it was a damaged s-video output connector on the back of the deck. It was obviously loose compared to the inputs on front and back. The pressing on/off of the TBC button on the unit may be nothing more than a jostling motion that causes the s-video port to unseat itself, and has nothing at all to do with the TBC.

It may need a repair, re-solder or replacement on the output jack. That's not overly difficult for somebody with experience at using a general electronics bench. The same part may be fine, but it's just not connected properly. Things like this can happen during shipping, too, so the deck may have worked fine when the seller sent it.

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  #8  
10-05-2012, 07:41 AM
juhok juhok is offline
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I also had a similar situation where DIN4/s-video connector had a hairline crack in the solder point. Re-solder + hot glue fixed the problem.
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  #9  
10-05-2012, 08:10 AM
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okay so update is that i managed to find an svideo input on a 2nd hand store tv , not far from where i live , and so tested on that screen , color worked fine completely when going straight into tv , tbc on no problem . . So where does that leave me , as far as fault finding goes . THanks for your help guys !
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  #10  
10-05-2012, 08:37 AM
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1. Was the same s-video cable used?
2. If so, then that leaves you an analyzing the s-video input on the other end -- the purple/domino box for the ATI AIW card. It may be the defect. And you'll need to replace it. Thankfully, those only cost $10 or so, plus a few dollars shipping.

You're also missing a full-frame TBC that I can tell. That may have a lot to do with it. Loss of chroma is an anti-copy side effect, and hardware detections in the digital capture/recording device may be to "blame" for it. Pretty much all hardware has this, so don't jump on the "ATI sucks" bandwagon, which is a common knee-jerk misguided response. You'll have to either get a real TBC, or some "Macrovision remover" type of device. The TBC always works reliably, the other... not so much.

If $200 ($USD) for a good external TBC (AVT-8710 or CTB-100) seems too costly long-term, then change the way you're thinking about it. You'll simply buy it now, use it, and resell it when you're done. The JVC decks and TBCs both hold their value long-term. So consider this a temporary investment, for the life of the project.

Those are the 3 options for fault:
1. No TBC.
2. Bad s-video cable.
3. Bad ATI cable.

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10-05-2012, 10:27 AM
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okay thanks for help , i think i must probably look into getting a full frame tbc , my preference would be avt 8710 , cheaper and has limited proc amp included . But there is the issue of not getting a defective one and also does the pal /ntsc thing come into it . Can you point me to a reliable seller , with high probability of properly functioning unit and will ship to cape town , south africa.

thanks
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  #12  
10-05-2012, 10:33 AM
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Outside of B&H in New York, I'm not really sure who else has reliable units right now. In fact, I'm sometimes not 100% convinced the AVT-8710 boxes from B&H are all 100% properly functioning. It's unfortunate that Cypress bungled the chipset on those problem units.

It may be safer to get DataVideo TBC-100 or TBC-1000 units.
Here's one on eBay for $350: http://www.ebay.com/itm/Datavideo-TB...item3ccad31e92

Granted, those cost more than the AVT-8710, but it may be better than gambling on a unit that's hard to return from South Africa.

There's also some TBC brands/models that a lot of people tend to overlook.
See the full list here: What is a TBC? Time Base Correction for Videotapes

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  #13  
10-05-2012, 10:38 AM
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http://www.markertek.co.uk/markertek?search=AVT-8710

I've bought stuff from this dealer in the UK. They were a bit slow to answer to emails and ignored some things altogether. Calling them directly helped. But they did deliver and prices are cheap.
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  #14  
10-05-2012, 10:59 AM
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Markertek is an old mail order catalog business, like B&H. They still send out annual catalogs, in fact. I have one on the bookshelf here. At minimum, there's the USA office, and the UK office. Not sure about other locales. Their pricing can be expensive, cheap, or about right. And like Amazon and B&H, it tends to change with the weather, so pricing today may be different tomorrow (for better or worse).

Adorama, B&H and Markertek are competitors.

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10-05-2012, 11:08 AM
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Markertek UK claims to have the lowest price and you can report if competitor is cheaper. I Used this feature and they almost halved the price of one expensive PSU module (the competitor was in another country). My complaint is that I didn't get refunded because I placed my order before the price decrease (it wasn't shipped yet). Emails regarding refund have been ignored.
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  #16  
10-06-2012, 09:51 AM
pete pete is offline
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I think im going to try and watch the used market on digital faq , to find a used avt 8710 tbc , as i would rather buy from someone who has a working tbc than take the chance on a new unit that hasnt been tested. They are quite small , so it wont be difficult to ship to South Africa , i ordered my aiw cards over the web and it was easy using US postal i think.

Please keep me informed if any long term / reliable members put any extra units up for sale .

thanks

Oh and just a quick thanks , each piece of equipment i have bought on this site s recommendation has added a noticeable improvement to my captures , i am still starting out and getting the proper settings and doing captures well takes time , but i can see there are definite improvements to be made once you become aware of all the common erros/ problems/ issues and its super rewarding when you get to see the detail from those old tapes coming back , thanks for all the guidance so far .....
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  #17  
10-07-2012, 05:22 PM
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Quote:
Oh and just a quick thanks , each piece of equipment i have bought on this site s recommendation has added a noticeable improvement to my captures , i am still starting out and getting the proper settings and doing captures well takes time , but i can see there are definite improvements to be made once you become aware of all the common erros/ problems/ issues and its super rewarding when you get to see the detail from those old tapes coming back , thanks for all the guidance so far .....
Glad to hear it.

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