OT: Need BIG help with 3/4" JVC deck

I need help with a JVC CR-6650U 3/4" U-matic deck.

I had a tape stuck in it when I was trying to shuttle the video...note to self: don't do that again! We managed to get the tape out by taking the thing half apart. The deck is still flashing the warning light, and there's no way that I can find to reset the machine. None of the buttons are operational, and nothing has worked so far.

I'm hoping there's some old-timers out here that have used one of these and remember what to do.

Funny thing, we haven't needed to use this deck for a customer in the 10+ years I've been here, and over two days, we've had two projects come in from two different customers...so naturally, I try to find out the duration of a tape, and the next thing I know, everything stops and the warning light blinks constantly and NOTHING works on it!

Here's a picture if it'll help jog your memories:


Any help would be appreciated!

Have you tried unplugging the machine? Many times, because there is power still going to the machine, the machine won't reset totally. Barry

I called a local JVC service place and all they said was to unplug it for a minute. I tried that and it didn't work. Maybe I'll leave it unplugged for longer.

Thanks!
Casey

Nobody uses GOOGLE anymore. I recommend you get THIS:

[cgi.ebay.com]

When life gives you dilemmas...make dilemmanade.

Yeah, I saw that already...actually a different one that was cheaper. I was hoping to find a quicker solution, and if I can't find one, then I'll be going this route! I didn't think this would be so hard to fix!

Thanks!
Casey

nice answer joe ; (

...nice answer yourself, wayne (?)

It just so happens a Service Manual I found on ebay for $25.00 helped me personally troubleshoot & fix a (what I thought was unfixable) Sony Studio Monitor & save a $2200 investment on a 10 + year old Broadcast CRT.

When life gives you dilemmas...make dilemmanade.

Oops, I hit the wrong button or something and Wayne's last response was deleted...
What happened there?!!


I was trying to say that I hope that would work as well for me if it comes down to that.

I'm cheap and I like free advice

Your welcome, Casey. Anytime

Cycling the power (unplugging for 15 - 30 minutes) may be the easy way out but if it isn't, the manual may help tremendously (includes exploded views of transport, internals, etc).

When life gives you dilemmas...make dilemmanade.

im sure it helped you joe. and its a good suggestion. but the guy needed help in a pinch and that's part of the tremendous (quick and free) value of this forum

there is no reason to be snide in your responses

Here's a faded memory from days of yore:

If you've got the top cover off, and can see the pc boards, look for a very tiny board-mounted button, black or red, on a metal base that's about a 3/16" square.

When pressed and held for a couple of seconds, it'll reset the transport mechanics and eject the tape carrier. Power cycle the deck, then see if it'll work with an undamaged tape...

I also remember power cycling the machine with the "eject" button held down- but I think that just forces the tape carrier up.

It was a long time ago.

Good luck. Those things were workhorses in there day.

tc

Thanks TC,

The eject button thing didn't work. I'm looking for a button...and there's like 6 boards in there...any idea which side or if I have to take one out to see if it's buried deep?

Casey

Sorry, CaseyPetersen, I don't recall.

Just be VERY careful of transformers, heads and components.
There's voltage in there.

Hey, is VTR Services still over in the Valley?

They are:

[www.vtrservice.com]
Might be worth a call

Good luck.

tc

Wouldn't know...I'm in Minneapolis. There is a local place, but I'd rather not bring it there if it's just a button or a series of buttons I need to push all at once. Again, this is a deck I haven't needed in 10 years, and probably won't need for a long time after this little project, so I don't want to spend much on it.

Thanks,
Casey

Casey-

Try calling Rick Dressler at Z-Systems in Minnetonka.

If he's familiar with that deck, and it's something you CAN do on your own, he'd be the honest guy to tell you how up front. If he truly believes it's not a user-serviceable issue, he'll give you an honest estimate on what it would take to fix it.

deb

Thanks....that's where we got our Mac

Called Rick and he remembers the deck, but not if there's a reset button of any sort. There is a big black button on the back that says BREAKER, but that doesn't help either. He also suggested looking for a broken belt, but I didn't see any belts at all in this thing...it's all motorized. I looked some more on the 12 boards for a magic button, but no luck.

Okay... It's been a couple 'a decades since I worked on one of these things, so my memory is really hazy...

However: Rick's probably right about the broken belt. As I remember ALL of the 3/4 machines used belts for driving the take-up & rewind spindles, the tape loading mechanism, and the head rotation assembly. Some used "idler" wheels to accomplish some of those tasks, but every machine had at least two belts. Belts generally last only 3-5 years, so it's quite likely that you've broken at least one of them. That also explains why the original tape jammed. The belts tend to dissolve, even when the machine isn't being used, ESPECIALLY if there are smokers in the area.

Look for brass-colored metal, white and black plastic pulleys. The broken belt will be a thin piece of black plastic sting, although I've seen one that looked like a piece of molten goo, melted onto the pulley, which needed to be cleaned. Belt replacement is sometimes a rather complex procedure, which really needs the service manual to explain just what you have to remove to get the belt replaced.

Good luck.

Travis
VoiceOver Guy and Entertainment Technology Enthusiast
[www.VOTalent.com]

That theory makes sense....I didn't see any belts at all when I took it apart though....but I didn't actually look under the reels....that might be the next place to check.

Thanks!!!
Casey

Okay, I opened up the front part and saw no evidence of belts. The two reels appear to be controlled independently by two large motors underneath. There wouldn't be any belts inside those motors, would there?

Okay... (Remember, it's been a long time, so I could be wrong on any of this, and I don't recall if I've worked on your specific model). No, the motors won't have belts inside.

There are four mechanisms in the machine.

(1) The supply spindle, which is used for rewind.
(2) The takeup spindle, which is driven to take up tape during recording/playback and fast forward.
(3) The head assembly, which spins the head on the tape.
(4) The tape loading mechanism, which loads the tape and wraps the tape around the head mechanism.

Each of these mechanisms needs to be driven. The most expensive machines dedicated a motor to each function, the cheapest machines used one or two motors and a complicated mechanism to apply power at the correct moments.

If the takeup mechanism fails, the tape will spill, and the machine will jam. If the loading mechanism fails, the tape cartridge will not load or ounload. If the supply spindle mechanism fails, the tape won't rewind. If the head drive mechanism fails, there will be no video. Many machines use sensors to shut down the machine if one of the mechanisms fails.

If the machine has only two motors, it's likely that each motor serves two functions - most likely the head rotation mechanism has it's own dedicated smaller motor. You can trace the power from each motor to it's particular function. If this is done through "idler" wheels, they can also melt and stick, so you may need to look for those.

Also, it's possible for a motor to jam, if the lubrication has dried out. Sometimes lubricating a motor will bring it back to life.

I still think the most likely failure is a broken belt, I don't remember ever owning or seeing a "direct-drive" 3/4 machine, though I could be wrong on that. Tracking down a maintenance manual would be a very good move - I've seen PDFs of those online in the past.

Travis
VoiceOver Guy and Entertainment Technology Enthusiast
[www.VOTalent.com]

This is a site that has manuals for OLD radio gear -Free

I did not look threw all of the site so I dont know if they
have deck manuals - but it may help you find the right
right place to look -- Jay --

[www.handheldaudio.co.uk]

Hi Casey,
I am having exactly the same problem.
Did you resolve the issue?
I see a paper stating : "Warning Reset Switch, when push this switch be sure tape transportation".
I do not see a switch per say.

Any help would be appreciated greatly,
Thank you,
Mailis

I kept reading the posts and I was able to fix the problem

You are awesome tc
I just had the exact same problem and your fix worked like a charm..
I am digitalizing over a 1000 tapes from our Finnish Church and they memories are so not replaceable..many many thanks.
Mailis - God Bless