dynamic drum fault fix
 

My HRS 9500EK had this fault, I cleaned the code disc and it would then play but with several track crossings, later it stopped playing at all and reverted to the shutting down after 3 seconds. The renewed fault was harder but eventually I found it was the dynamic drum system. One of the gears had split so it had jammed in the fully tilted position, no chance of a replacement apparently only complete drums are supplied for something like £300. I tried replacing the drum with a fixed drum but no go. Then I adjusted the gears to set the tilt of the drum in mid tilt so to speak, I then removed the gears that operated the tilt screws. Now the machine received the tachs from the DD tilt board and will play tapes, after a tape path tweak. Nice to fool a system.

if you remove the gear/motor assembly from the bottom of the DD and plug it into the motherboard then install a fixed drum it will work - albeit minus the timescan and other DD properties.

i would not remove the gears and reinstall the DD - it can move around if that is done and you would have to constantly adjust it.

Dynamic Drum seems to be a timebomb - eventually the majority will suffer with this issue. Why oh why does not JVC help out owners who have shelled out big amounts of cash for premium VCR's at least offer a repair kit?

I only removed the gears, they pop off the threads that actually tilt the drum so the drum is firmly fixed. I would not like the drive mechanism just plugged into the socket rather likely to jiggle out I would think

a small dab of silcone RTV holds it firmly in place.
plus the socket is fairly tight fitting and it cant come unplugged as it has nowhere to go.

just make sure your drum cant move - on the ones ive done they can move without thegears in place

Thanks Blackout! Wife and kids are happy thanks to you!

http://www.digitalfaq.com/forum/imag...earbox01-1.jpg

http://www.digitalfaq.com/forum/imag...earbox02-1.jpg

thats the 9900
is that gear box included in the

LP20319-019A DRUM SUB ASSY
or the
LPA20002-01C SENSOR BOARD ASSY

-- merged --

you cant get the LPA20002-01C anywhere!
few webpages say they can get it, but if you try to order it, no one can =/

I just purchased a JVC HR-S7500U with the symptom of shutting off almost immediately after "VIDEO CALIBRATION" begins after inserting a tape. When I power on the deck, I hear a "whirr-whirr" and see the two small black gears moving. I've tried several times to rotate the gears with my fingertip during powering on the deck with no change in symptoms. I have removed the drum from the deck and as far as I can tell, the gears are not cracked or damaged in any way.

Am I dealing with some other issue here, or should I simply keep trying with rotating the gears manually?

-- merged --

The gear is cracked on the drum, see attachment.

I have a broken SR-V10U. I installed the lower DD assembly and the SR-V10U drum, but when I attempt playback the tape path is very obviously misaligned. How can I correct it?

EDIT: Oops, most novice mistake on the planet: plugged the top connector in upside down and let out the magic smoke for the motor control board of the SR-V10U drum.

I've put the 7500's motor control board on the SR-V10U drum, and it powers on and the drum spins now. Still can't get past the same "video calibration" issue - I see a frame for a second with "VIDEO CALIBRATION" flashing, then it turns off. I also cannot rewind or fast forward; it whirrs, then turns off. Any further ideas?

It would seem that the lower DD unit does not have any cracked gears, and I hear it "whirr-whirr" on power on.

I'm a sometime lurker who became a member in order to access the photos in this thread. When I recently fired up my precious JVC HR-S9600U for the first time in a long while to transfer a tape, I experienced the symptoms -- powers up fine, put in tape, and it turns off in three seconds, hit eject and it powers up to eject.
The advice here worked perfectly. I opened up the case and massaged those little black gears while turning it on several times. Nothing dramatic seemed to happen, but the player now works fine.
Hopefully this can keep it working until something more major gives out.

Blackout, Have you taken a note of the part # of the rotating drum on your HR-S7600AM deck? Is there a way to get the part # without pulling the head assembly out?

I was able to get my HR-DD857MS back to life by nudging the gears on power up - many thanks for posting the tip.
Using the jog/shuttle too much sometimes causes it to need nudging again, but at least it can play well enough for transferring old tapes.
Also after winding and then restart playing, the B.E.S.T. routine seems to struggle, give up and automatically eject the tape, but in all cases reinserting and hitting play gets it going again.
Not bad for a unit that's been stuck in a basement for about 10 years...

Thank you, Blackout!! Exactly what I needed. JVC HR-S4500U

I must say this is an amazing find.
Never would have found this.
In the past broke this gear on a JVC 9800 and it was a nightmare to put in a rigged gear to do the job.

Many thanks again....

Just have to say that helped me fix my very odd problem I was having trying to fix a high end VCR - thanks.
The bright light of the room with cover off was messing up with tape loading.

Wow...this is a pretty old thread! But I am glad I found this. It seems this is more of a popular issue than I thought.

I apparently have the same problem as Blackout had. My VCR is the JVC HR-S9800U. Mine came into the "3 second power down issue" just after scanning a tape.

So, off to Google to search for fixes. Found this thread. I wish I could see if wiggling the little black gears will solve my issue (as I bet it will) but NOW, the unit will not power up just after I tried the trick of pressing the power button on the remote down for 7 seconds or so. Since then, the unit will not power up at all. Just "auto" blinks on the screen. Ahh great! Trying to fix one issue...and in the process created a new one. Ugh...

What next? Blackout? Volksjager? Anyone?

I have to coax my 9800U a few times per year. I've actually semi-retired my deck in favor of others, because of this issue. I reserve it now for tapes that fail in at least 3 others first.

I'm not aware of the 7-second "fix" (or forgot), but it honestly doesn't sound right. I could actually see how holding down the power button could case problems. The internal wiring/soldering of 9500/9800/9900 is actually not the best on the front buttons and back svideo/composite block. You may have damaged it. If so, the fix is a re-solder job. At very least, dismantle it and visually inspect it.

Well actually, Blackout had mentioned the "hold down the power button for 7 seconds" in this very same thread earlier on (first post). I don't think he would recommend to do if it would damage something?

Quote: NOTE THAT THE UNIT NEVER SHOWS "AUTO". I REPEAT....THERE IS NOT "AUTO" ON THE SCREEN AT ANY TIME. The old "hold down power for 7 seconds on remote" trick does not make a difference.

In my case, this "holding the power button down" procedure made my issue worse.

I've had the case opened previously to fix the 3 second power on issue, but I don't see anything anything out of the ordinary as far as bad solder joints or whatever. I also don't see how front buttons could physically go bad when I used the remote.

This thread was start 5+ years ago, so I don't remember what all it says anymore. :o

Even if a valid idea, it can still damage. The mere act of plugging/unplugging cables too much is what damages the input block in back. It's just use wear on a deck that has somewhat weak soldering work in some areas. So still very possible.
Remote. I missed that. :smack: ... just regard what I wrote. :laugh:

I really have no idea at this point. Hmm... :hmm:

[QUOTE=lordsmurf;52018]This thread was start 5+ years ago, so I don't remember what all it says anymore. :o

True that! I've had a few and slept since then myself. I even forgot I belonged to this forum. lol

Thanks for playing anyway buddy. Maybe someone has a little insight on this deal.

I've seen this problem like 4 or 5 times over the last year with JVC decks, meaning dead power. To trace the problem is very hard normally just trash the machine. However when dealing with the same issues with a 9800 when I tested the machine about 2 months later it did power up however the front panel was messed up electronic codes.

This problem is more than likely a fuse problem mixed with a capacitor resistor issue. However if the board has shorted the unit is dead.

The plastic gear part, which they do break, is about $225 to $250 for the part (to install at least $100) found one vendor who sell this, for my own machine a 9900, paid for the part and than replaced it. It was not easy to repair. The only reason I did it this was the unit is the best playing 9900 I've have seen. Sometimes it is worth it.