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Crumbtrail TV Forums: TV Equipment: VCR Repair Forum:
JVC BR-S800U issues.. (..and Sony UVW-1800)

 

 


Veepa
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Aug 24, 2010, 2:20 PM

Post #1 of 9 (4685 views)
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JVC BR-S800U issues.. (..and Sony UVW-1800) Can't Post

I'm not sure if this player requires any repair, or if I just have something set wrong.. Anyway..

So I have a JVC BR-S800U. I bought it primarily for playback, because I assume since it's a professional model the playback quality would be superior, plus I got a pretty good deal on it. I just bought it today, and I really know nothing about all these features it has and I'm just trying to get it to play a standard commercial VHS ... but when I hit play, the picture just jumps around constantly, and messing with the tracking doesn't even really affect it.. so I'm just assuming that maybe I have something on the wrong setting? I've tried the tapes in other players, and they work fine. EDIT: Here's a picture of what I mean by jumps around: http://img.photobucket.com/albums/v700/Veepa/jumpy.jpg
Also I should add that the audio from the tape sounds fine. There's no distortion or static.


And I also bought today.. a Sony Betacam SP UVW-1800. I tested out one of the Betacam SP broadcast tapes in it, and it seems to play fine. But this unit also plays Betamax tapes... but when I put a commercial Betamax in the player, it will play or at least the player says it's playing, but the picture is just black. I really don't know much about this, and whether it's even designed to be able to play commercial Betamax tapes. I know it's made for professional video-editing.

Anyway, I hope someone on here knows something about these models and can help me out.

Thanks in advance.



Barry777
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Aug 31, 2010, 1:55 AM

Post #2 of 9 (4670 views)
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Re: [Veepa] JVC BR-S800U issues.. (..and Sony UVW-1800) [In reply to] Can't Post

Hi Veepa,
The JVC BR-S800U is indeed a great player, costing more than $3000 when they were new. I have two of those, two S500's (same unit without the recording functions), plus three BR-S822U's and a few of the BR-7000 series. I guess you could say I'm a huge fan of JVC VCR's, and also have a fully equipped electronics shop to keep them in good working order.

First, let's reset everything to how it came from the factory. To do this, hold down "Counter Reset" and "Eject" together while turning the unit on. Now all the mysterious and invisible menu settings are set for "normal" operation and a standard tape should play just fine.

But of course it won't - I can see from the picture that there is an actual circuit problem. So my first guess is that you're missing the PG pulse, which keeps the picture locked in. If you feel daring, take the bottom cover off, then unscrew the 2 screws that hold the largest board in place. The screws are captive and won't come out all the way. Once the screws are loose, gently pull off the long white connector closest to the screws, then gently pull out the 2 very thin ribbons on the side of the board. Now you should be able to gently swing that board out and see the bottom of the mechanism.

Without touching the sides of the video head drum, give it a little spin so you can see where it is from the bottom of the unit (you do have the unit on its side, right?). You'll see the lower drum spin when you do this. There is a small circuit board attached to the lower drum, and on that board you'll see one tiny silvery-looking cylinder standing up. If you look closer, you'll be able to read the value which should be 3.3 uF at 50 volts. This is the capacitor that processes the PG pulse from the head drum, and the picture looks like that puppy is either leaky or open. You can replace it with a standard 3.3 uF, 50 volt electrolytic capacitor which is easier to find and probably cheaper. Notice that the existing capacitor has a black stripe on one side - this is the negative side, and the new one MUST be installed the same way. A standard electrolytic won't look anything like the original, but will still have the negative stripe down one side.

Replace that, then we'll go from there if needed. It could also be a bad video head or some other circuit problem, but you would need some test equipment and electronics knowledge to do any effective troubleshooting. We'll start with the most common causes first - and of course you've already tried cleaning the video heads?

On the Sony: Even though the tapes are the same size and shape, Betacam is an entirely different format than Betamax and likely won't play a standard Betamax tape. Betacam was the professional industry standard before everything went digital, and they designed the Betacam format to be able to use a standard Betamax tape in an emergency with reduced quality. This enabled the professional field videographer to easily obtain emergency blank tapes at the local outlets when needed, rather than being dead in the water on an important shoot. This idea, obviously, was generated before VHS pushed Beta out of the picture and you could buy blank Beta tapes in most stores.

The machine should play its own recordings using a standard Beta tape, but probably won't play any tapes recorded in the Betamax format. The process of recording, processing and playing video is incredibly complex, and it's simply not possible to juggle formats except by dubbing - and even that is sometimes impossible without extra equipment.
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Barry Fone - VCR Repair hobbyist and professional FAA Repair Station Avionics Bench Technician (top level). TEST EQUIPMENT: (4) Sencore VC93 VCR Analyzers, (11) Tentel gauges, Sencore VA48 and (2) VA62 Video Analyzers, Sigma Electronics TSG-375 NTSC/SMPTE Video Generator, several VCR Alignment Tapes, plus countless Oscilloscopes, Frequency Counters, Wow and Flutter Meters, Distortion Analyzers, Vectorscope, 136-channel Logic Analyzer, Signature Analyzer . . . . VIDEO GEAR: (6) JVC BR-S822U's, (3) JVC BR-7000 series, (3) JVC BR-S500U, (2) JVC BR-S800U, JVC GR-800U and (2) GR-860U Editing Controllers, Sony FXE-100 Video Switcher/Effects Generator, (5) Time Code Generator/Readers, (1) Sony SLO-1800 (Beta), (2) Alesis ADAT-XT, (1) Sony DXC-1200 TV Camera, Pioneer VP-1000 Laser Disc Player plus many consumer grade Beta and VHS VCR's. Passionate electronics enthusiast since 1973...most anything except computers. Check out my collection at www.barrys8trackrepair.com/MyVideoGear.html

(This post was edited by Barry777 on Aug 31, 2010, 2:24 AM)


Veepa
New User

Aug 31, 2010, 3:19 AM

Post #3 of 9 (4666 views)
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Re: [Barry777] JVC BR-S800U issues.. (..and Sony UVW-1800) [In reply to] Can't Post

Thanks a lot for your reply. I really appreciate it.

I have tried cleaning the heads, but it didn't change anything.

I should mention that lately I've been messing around with different tapes, and I can occasionally get a picture that isn't nearly as distorted as the screenshot above.. I can get a pretty clear picture of what I'm suppose to see, but in front of the picture is some distortion and what can only be described as flickers of white spikes. Very strange.

I did as you said, and located the little cylinder thing marked 3.3 uf on it. But it didn't look leaky or anything. Do you still think that would be the culprit?

Now,.. I assume to replace this thing I'd have to solder it on. Which I've never really soldered anything before, but if it isn't difficult I'm sure I could handle it. (I'm mostly into old VCRs and stuff as a hobby because I like to take old programs and things that are recorded and create digital versions, to preserve films or tv shows that have never been released onto DVD)


Barry777
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Aug 31, 2010, 5:16 AM

Post #4 of 9 (4662 views)
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Re: [Veepa] JVC BR-S800U issues.. (..and Sony UVW-1800) [In reply to] Can't Post

Hi Veepa,

I forgot to mention that a leaky or open capacitor usually won't show any external signs of anything wrong - the problem often remains inside the component and can't be seen. From your description of the occasionally good picture, that cap is looking more and more like the culprit. Let me see if I can explain it a little:

The video signal is laid down in the form of long, diagonal strips on the tape. You'll note that the head drum is at an angle, thus wiping across the tape not quite parallel to the edge, but at a slight angle. Each diagonal "stripe" represents one line of video information. By one "line", I mean the type of extremely thin horizontal lines you can see on any CRT based TV, especially if you move your eyes slowly up or down since the lines also appear to move.

Now, the VCR must play back those lines the same way they were recorded: Head "A" must play back the same line that was laid down by Head A on the recording machine. To keep this critical timing intact, a multitude of control signals are produced by the VCR: A series of pulses on the bottom edge of the tape called the control track (30 pulses per second), a once-per-revolution pulse produced by the video head drum spinning at 1800 RPM, also a pulse produced by the capstan. Then you have the synchronizing pulses contained in the video signal itself - namely the horizontal sync pulse and the vertical sync pulse. The circuitry in the VCR evaluates all these signals, and manipulates the speed of mechanical things to keep them all locked together.

All of this stuff - all of it - must always be kept in perfect synchronization for the video to play properly, which means that all control and timing pulses must be present, and at precisely the right times. The video head drum actually speeds up and slows down many times per second as required to keep itself from running ahead or behind the other stuff. If you lose just one of these control signals, the entire VCR gets confused and can no longer produce a good picture. However, there will always be times when the unit IS in sync for a brief moment, but only because everything just happens to be at the right place - then it quickly drifts back out of sync.

If you're missing the PG pulse, you lost one of the most critical timing devices. The picture may come in and out (mostly out), and can very closely resemble the intense flicker of a bad video head. But if you get a nice clear picture for an entire second, then your video heads are probably fine. A bad video head produces a very steady flicker, and you never get a full clear picture. The white flashes of light on the screen are either timing errors, worn spots on the tape (causing the timing errors), or arcing inside the head drum from dirty bearings that no longer make good contact.

I should point out that NONE of these ailments have any effect on the audio, since the audio is produced by an entirely different system. That PG capacitor is looking awfully good as the suspect.

To replace it, yes you'll have to solder. It won't be too hard in this instance - just make sure not to pull up the tiny copper pads on the circuit board. Heat one side of the cap, pull gently. Then heat the other side. Keep doing this until it finally comes off the board. The new one will be easier to solder in, since it will have actual leads (wires) coming from it. Just solder that baby in, making sure it can't contact the spinning lower drum.

If that cap was the problem, you'll immediately be rewarded with a nice, clear picture. Remember to play with the tracking control if needed. If there's no improvement, we'll have to check into other possibilities.
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Barry Fone - VCR Repair hobbyist and professional FAA Repair Station Avionics Bench Technician (top level). TEST EQUIPMENT: (4) Sencore VC93 VCR Analyzers, (11) Tentel gauges, Sencore VA48 and (2) VA62 Video Analyzers, Sigma Electronics TSG-375 NTSC/SMPTE Video Generator, several VCR Alignment Tapes, plus countless Oscilloscopes, Frequency Counters, Wow and Flutter Meters, Distortion Analyzers, Vectorscope, 136-channel Logic Analyzer, Signature Analyzer . . . . VIDEO GEAR: (6) JVC BR-S822U's, (3) JVC BR-7000 series, (3) JVC BR-S500U, (2) JVC BR-S800U, JVC GR-800U and (2) GR-860U Editing Controllers, Sony FXE-100 Video Switcher/Effects Generator, (5) Time Code Generator/Readers, (1) Sony SLO-1800 (Beta), (2) Alesis ADAT-XT, (1) Sony DXC-1200 TV Camera, Pioneer VP-1000 Laser Disc Player plus many consumer grade Beta and VHS VCR's. Passionate electronics enthusiast since 1973...most anything except computers. Check out my collection at www.barrys8trackrepair.com/MyVideoGear.html


jts1957
Veteran


Aug 31, 2010, 5:52 AM

Post #5 of 9 (4661 views)
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Re: [Barry777] JVC BR-S800U issues.. (..and Sony UVW-1800) [In reply to] Can't Post

I find it quicker and safer to grab the cap with needle-nose pliers and twist it in either direction until removed. The leads will break off or pull out before the foils on the board will lift, assuming it is first time being removed.
Then take tip of a solder iron and wearing magnifiers, touch one pad, removing lead remnant, repeat for other lead. Melt a little dab of fresh solder on each pad and also tin shortened/formed as necessary leads of new standard lytic. Paying attention to polarity, heat one pad and rest lead in molten solder, remove iron and let solidify, repeat for other lead.Wink


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Location: Far, Far Away


Barry777
User


Aug 31, 2010, 12:39 PM

Post #6 of 9 (4657 views)
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Re: [jts1957] JVC BR-S800U issues.. (..and Sony UVW-1800) [In reply to] Can't Post

NO, DON'T DO IT THAT WAY !!!!!

That's putting too much trust in the integrity of the circuit board. This board is not covered in the service manual since it's part of the lower drum assembly. Thus, there is NO schematic on this board anywhere. If by chance a pad does break off and it's a multilayer board (traces hidden), there may be no way to figure out how to wire the new cap into the circuit except by a seasoned technician. I would not recommend that a layman use this technique in this case.

I work on surface mount stuff Monday through Friday - and I can't go along with this suggestion. Sorry jts.....
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Barry Fone - VCR Repair hobbyist and professional FAA Repair Station Avionics Bench Technician (top level). TEST EQUIPMENT: (4) Sencore VC93 VCR Analyzers, (11) Tentel gauges, Sencore VA48 and (2) VA62 Video Analyzers, Sigma Electronics TSG-375 NTSC/SMPTE Video Generator, several VCR Alignment Tapes, plus countless Oscilloscopes, Frequency Counters, Wow and Flutter Meters, Distortion Analyzers, Vectorscope, 136-channel Logic Analyzer, Signature Analyzer . . . . VIDEO GEAR: (6) JVC BR-S822U's, (3) JVC BR-7000 series, (3) JVC BR-S500U, (2) JVC BR-S800U, JVC GR-800U and (2) GR-860U Editing Controllers, Sony FXE-100 Video Switcher/Effects Generator, (5) Time Code Generator/Readers, (1) Sony SLO-1800 (Beta), (2) Alesis ADAT-XT, (1) Sony DXC-1200 TV Camera, Pioneer VP-1000 Laser Disc Player plus many consumer grade Beta and VHS VCR's. Passionate electronics enthusiast since 1973...most anything except computers. Check out my collection at www.barrys8trackrepair.com/MyVideoGear.html


jts1957
Veteran


Aug 31, 2010, 3:22 PM

Post #7 of 9 (4656 views)
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Re: [Barry777] JVC BR-S800U issues.. (..and Sony UVW-1800) [In reply to] Can't Post

To each their own.Cool


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Location: Far, Far Away


Veepa
New User

Sep 2, 2010, 10:59 PM

Post #8 of 9 (4635 views)
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Re: [Barry777] JVC BR-S800U issues.. (..and Sony UVW-1800) [In reply to] Can't Post

Thanks again for all the info, Barry..

I haven't attempted replacing that capacitor yet, but I have another question regarding the same model VCR..

So the same thrift store I found the other one at, I found another one. Same model. I was hoping this one would work, but it also has something wrong with it.. From the looks of it, it might be even worse.

It powers on and everything, but when I put a tape in .. it sounds like it's going to start the tape, but then suddenly the mechanism just stops and the on-screen text says "WARNING 701 - MOTOR DRUM FAILURE" and the display on the VCR says "Er 701" So.. to me that sounds pretty serious.. but I don't really know much about this stuff. Any info?

EDIT!: Okay, uhm.. this is strange.. I tried playing it twice, and it did the same thing.. but when I turned off the VCR with the tape in there after the error.. and turned it back on.. And then it let me play the tape. And everything seemed to be working fine. And I just tried popping another tape in, and it's playing as we speak. Seems to be okay. What's with that error I got the first time?

The quality doesn't really seem very much better than my consumer grade VCR, though.. Maybe I need to clean the video heads. This VCR has a built in TBC, doesn't it? Does it work automatically or do I have to mess around with the settings to have it work?

Again, thanks for all the info you've given me, and anymore info you can offer.


(This post was edited by Veepa on Sep 2, 2010, 11:13 PM)


Barry777
User


Sep 2, 2010, 11:51 PM

Post #9 of 9 (4630 views)
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Re: [Veepa] JVC BR-S800U issues.. (..and Sony UVW-1800) [In reply to] Can't Post

Hi Veepa,

Sounds like your most recent acquisition was simply sluggish from gummed up lubricant until you cycled it a few times. It should be fine now, especially if you keep using it regularly. The JVC pro VCR's have a weird error reporting method, in which a motor failure will be indicated if something else is causing the motor to slow down, but the motor itself is fine. The same applies to the reel motors and other major components. Very seldom will an error message indicate an actual failure.

The 800 doesn't have a built-in TBC, and it is only an option on the 822's I have. Some folks confuse a TBC with a TCG (Time Code Generator) which both of yours may have. I have the user and service manuals on my website if you'd like to download them - reading them will answer many questions and enable you to figure out all the machines will do:

www.barrys8trackrepair.com/JVC.html
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Barry Fone - VCR Repair hobbyist and professional FAA Repair Station Avionics Bench Technician (top level). TEST EQUIPMENT: (4) Sencore VC93 VCR Analyzers, (11) Tentel gauges, Sencore VA48 and (2) VA62 Video Analyzers, Sigma Electronics TSG-375 NTSC/SMPTE Video Generator, several VCR Alignment Tapes, plus countless Oscilloscopes, Frequency Counters, Wow and Flutter Meters, Distortion Analyzers, Vectorscope, 136-channel Logic Analyzer, Signature Analyzer . . . . VIDEO GEAR: (6) JVC BR-S822U's, (3) JVC BR-7000 series, (3) JVC BR-S500U, (2) JVC BR-S800U, JVC GR-800U and (2) GR-860U Editing Controllers, Sony FXE-100 Video Switcher/Effects Generator, (5) Time Code Generator/Readers, (1) Sony SLO-1800 (Beta), (2) Alesis ADAT-XT, (1) Sony DXC-1200 TV Camera, Pioneer VP-1000 Laser Disc Player plus many consumer grade Beta and VHS VCR's. Passionate electronics enthusiast since 1973...most anything except computers. Check out my collection at www.barrys8trackrepair.com/MyVideoGear.html

 
 
 


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