Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Daniele - Skrauso
 
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Default JVC vintage videorecorder

Hi,
I got (for free) an old JVC videorecorder. It still has direct mechanical
tape controls (play, ffwd, rew, ecc) without any servo-system. The motors
appear to be OK, ffwd e rew work fine but the play key dowesn't work. The
problem is that the key is locked, if you try to push it you cant get it
down. I opened the machine and I think it's possible that some lever isn't
free to move for some reason.

Another possibility is that one of the magnets that helps moving the levers
inside is out of order.

Is there anyone experienced with those old and wonderful videorecorders? I'm
going to cry if I had to trhow it away :\

Thanx
Daniele

--

http://tastiere.altervista.org - THE resource for Synthesizers !
Free patches and sounds

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Tim Schwartz
 
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Default JVC vintage videorecorder

Daniele,

A shot in the dark that people may have forgotten about. Is the end
stop LAMP burned out? Many old machines have end stop sensor lamps and
will not function if the bulb is out. My long gone JVC HR-6700U did, as
did the HR-7300U after that.

Regards,
Tim Schwartz
Bristol Electronics

P.S. If you post further questions about this machine, you'll likely
get better answers if you include the model number.

Daniele - Skrauso wrote:

Hi,
I got (for free) an old JVC videorecorder. It still has direct mechanical
tape controls (play, ffwd, rew, ecc) without any servo-system. The motors
appear to be OK, ffwd e rew work fine but the play key dowesn't work. The
problem is that the key is locked, if you try to push it you cant get it
down. I opened the machine and I think it's possible that some lever isn't
free to move for some reason.

Another possibility is that one of the magnets that helps moving the levers
inside is out of order.

Is there anyone experienced with those old and wonderful videorecorders? I'm
going to cry if I had to trhow it away :\

Thanx
Daniele

--

http://tastiere.altervista.org - THE resource for Synthesizers !
Free patches and sounds

  #3   Report Post  
Steve(JazzHunter)
 
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Default JVC vintage videorecorder

On Mon, 19 Jan 2004 12:57:28 GMT, Tim Schwartz
wrote:

Daniele,

A shot in the dark that people may have forgotten about. Is the end
stop LAMP burned out? Many old machines have end stop sensor lamps and
will not function if the bulb is out. My long gone JVC HR-6700U did, as
did the HR-7300U after that.

Regards,
Tim Schwartz
Bristol Electronics

P.S. If you post further questions about this machine, you'll likely
get better answers if you include the model number.


I think that's exactly what it is. On the original JVC Vidstar if the
lamp, both incandescent and infrareds were used, is burned out or
defective the tape will fast forward and rewind, at the risk of
breaking the tape at the end, but the Play button is locked out.


. Steve .

Daniele - Skrauso wrote:

Hi,
I got (for free) an old JVC videorecorder. It still has direct mechanical
tape controls (play, ffwd, rew, ecc) without any servo-system. The motors
appear to be OK, ffwd e rew work fine but the play key dowesn't work. The
problem is that the key is locked, if you try to push it you cant get it
down. I opened the machine and I think it's possible that some lever isn't
free to move for some reason.

Another possibility is that one of the magnets that helps moving the levers
inside is out of order.

Is there anyone experienced with those old and wonderful videorecorders? I'm
going to cry if I had to trhow it away :\

Thanx
Daniele

--

http://tastiere.altervista.org - THE resource for Synthesizers !
Free patches and sounds


  #4   Report Post  
jakdedert
 
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Default JVC vintage videorecorder


"Steve(JazzHunter)" wrote in message
...
On Mon, 19 Jan 2004 12:57:28 GMT, Tim Schwartz
wrote:

Daniele,

A shot in the dark that people may have forgotten about. Is the end
stop LAMP burned out? Many old machines have end stop sensor lamps and
will not function if the bulb is out. My long gone JVC HR-6700U did, as
did the HR-7300U after that.

Regards,
Tim Schwartz
Bristol Electronics

P.S. If you post further questions about this machine, you'll likely
get better answers if you include the model number.


I think that's exactly what it is. On the original JVC Vidstar if the
lamp, both incandescent and infrareds were used, is burned out or
defective the tape will fast forward and rewind, at the risk of
breaking the tape at the end, but the Play button is locked out.


. Steve .

Daniele - Skrauso wrote:

Hi,
I got (for free) an old JVC videorecorder. It still has direct

mechanical
tape controls (play, ffwd, rew, ecc) without any servo-system. The

motors
appear to be OK, ffwd e rew work fine but the play key dowesn't work.

The
problem is that the key is locked, if you try to push it you cant get

it
down. I opened the machine and I think it's possible that some lever

isn't
free to move for some reason.

Another possibility is that one of the magnets that helps moving the

levers
inside is out of order.

Is there anyone experienced with those old and wonderful

videorecorders? I'm
going to cry if I had to trhow it away :\

Thanx
Daniele

--

http://tastiere.altervista.org - THE resource for Synthesizers !
Free patches and sounds

That sounds like it...to the OP, if you get it working, you still have a
large job of replacing all the rubber in the machine, if you want to get
original performance out of it. I agree that these early VCR's were marvels
of mechanical engineering. Eventually they developed error correcting
electronics which made production of less heavy/precise/robust mechanical
assemblies possible, while sacrificing nothing in picture quality. Further
on, they carried that trend to such extremes that nowadays, most VCR
transports are flimsy plastic/sheet metal crap that wears out or breaks
almost out of the box.

jak




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Daniele - Skrauso
 
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Default JVC vintage videorecorder

Hi all guys,
thanx for answering. You're right! It's lame not to post the model #: JVC
HR3660.
Now.. you say there's a problem about lamps. I noticed there are 2 optical
components near the tape slot but I couldn't imagine what they standed there
for.
you say that their function is to check if the tape is at the end in order
to stop the motors and release play key.
I noticed that ffwd and rew keys are instantly auto-released if I try to
press them without a tape in the slot (but pressing woth a finger the switch
under the tape). so at least one of those optical controls still works.
but can you tell me more about these lamps? is there a sort of reflected
light system which checks the light reflected by te tape?

now the question: is there a way in your opinion to cheat that lamps? I
mean.. a way to let the hardware believe and that everything is alright?
maybe placing a resistor instead of the lamp or cheating the
electro-mechanical controls that the light itself controls

Thanx a lot guys!

Bye
Daniele


--

http://tastiere.altervista.org - THE resource for Synthesizers !
Free patches and sounds



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Daniele - Skrauso
 
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Default JVC vintage videorecorder

That sounds like it...to the OP, if you get it working, you still have a
large job of replacing all the rubber in the machine, if you want to get
original performance out of it.


well... it would be a miracle if I get i working . Then I could also
replace rubbers.

I agree that these early VCR's were marvels


you know man.. I'm young. The first videorecorder I had in my house was
servo controlled, at the and of 80's. when it died few months ago i opened
it... there already was a high integration rate, but maybe nothing in
comparison with my actual one, its weight is less than half of his
predecessor.
when I got this JVC.... I was frightened of its weight. And I don't hide you
how I was surprised to see that inside there are only discrete components...
the power section isn't in switching technology (a huge transformer!!) and
the tape control is simply cute. several boards interconnected with free
coloured wires without those boring flat cables (like ide interfaces ones).
I only can imagine the great amount of knowhow essential to project that
circuits! from the RF to the signal processing........ good old times!

Bye
Daniele

--

http://tastiere.altervista.org - THE resource for Synthesizers !
Free patches and sounds

  #7   Report Post  
James Sweet
 
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Default JVC vintage videorecorder


"Daniele - Skrauso" wrote in message
...
Hi all guys,
thanx for answering. You're right! It's lame not to post the model #: JVC
HR3660.
Now.. you say there's a problem about lamps. I noticed there are 2 optical
components near the tape slot but I couldn't imagine what they standed

there
for.
you say that their function is to check if the tape is at the end in order
to stop the motors and release play key.
I noticed that ffwd and rew keys are instantly auto-released if I try to
press them without a tape in the slot (but pressing woth a finger the

switch
under the tape). so at least one of those optical controls still works.
but can you tell me more about these lamps? is there a sort of reflected
light system which checks the light reflected by te tape?

now the question: is there a way in your opinion to cheat that lamps? I
mean.. a way to let the hardware believe and that everything is alright?
maybe placing a resistor instead of the lamp or cheating the
electro-mechanical controls that the light itself controls

Thanx a lot guys!

Bye
Daniele


You need the lamp working, it serves a useful function. It's just a small
incandescent light bulb, it shouldn't be hard to find something that'll work
in it's place.


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Daniele - Skrauso
 
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Default JVC vintage videorecorder

if the
lamp, both incandescent and infrareds were used, is burned out or
defective the tape will fast forward and rewind, at the risk of
breaking the tape at the end, but the Play button is locked out.


breaking news!
I had that light-based tape control under my eyes but I didnt realize what
it was :\
anyway, after few testing I discovered this: the lamp is a normal (well
visible!!) working light (no led, no infrared). The sensors seem to work: if
I push the tape switch and cover with fingers (without tape inside) the
sensors ffwd and rew works. if I put my finger away (from end or start
check) ffwd and rew respectively automatic stops. So I suppose that the
check system still works.
But playing with fingers doesn't solve the play button problem Is it
known where these machines has the play-lock switch (mechanically speaking)
? Maybe finding it will lead to discover the broken electro-mechanical
device.

Thanx again!

Bye
Daniele

--

http://tastiere.altervista.org - THE resource for Synthesizers !
Free patches and sounds

  #9   Report Post  
Steve(JazzHunter)
 
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Default JVC vintage videorecorder

On Mon, 19 Jan 2004 23:37:35 +0100, "Daniele - Skrauso"
wrote:

if the
lamp, both incandescent and infrareds were used, is burned out or
defective the tape will fast forward and rewind, at the risk of
breaking the tape at the end, but the Play button is locked out.


breaking news!
I had that light-based tape control under my eyes but I didnt realize what
it was :\
anyway, after few testing I discovered this: the lamp is a normal (well
visible!!) working light (no led, no infrared). The sensors seem to work: if
I push the tape switch and cover with fingers (without tape inside) the
sensors ffwd and rew works. if I put my finger away (from end or start
check) ffwd and rew respectively automatic stops. So I suppose that the
check system still works.
But playing with fingers doesn't solve the play button problem Is it
known where these machines has the play-lock switch (mechanically speaking)
? Maybe finding it will lead to discover the broken electro-mechanical
device.


First, make sure the two tape loading arms are completely unloaded, so
that the tape unload switch being activated by the loading gear
underneath is pressed. Secondly you may be right about a mechanical
issue. The FF and RW levers are freed by default. However once the
tape is loaded into the hatch and the door pressed down, with the
loading arms at rest as noted, a solenoid should pull a couple of bars
under the levers releasing the play lever and locking out the record
button. If the record CAN be pushed down (unloaded E - E) then this
solenoid is not doing its job. It may be weak, a common fault, or the
driver transistor for the solenoid may be open, another common
failure, or crud has got in the well freezing up the solenoid bolt,
not a common problem. I had the manual for this machine somewhere.
I'll try to find it.

. Steve .

Thanx again!

Bye
Daniele


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Daniele - Skrauso
 
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Default JVC vintage videorecorder

First, make sure the two tape loading arms are completely unloaded, so
that the tape unload switch being activated by the loading gear
underneath is pressed.

[...]

I checked what happens when the tape is inside: the switch is pressed (if it
wasn't nor ffwd or rew would work.. tested). But when the tape is inside I
cant hear or see any solenoid working. In the whole machine I found 2
solenoids: one commands every automatic stop and works perfectly. I never
saw the other working: surely it's related with play.. if I move by hand the
levers I see another lever with a head upon it getting closer to the tape
location. On the other hand rec buttons are never enabled.
The strange thing is this: even trying to move any lever inside the videorec
by hand, I wasn't able to enable play button...
Another thing: there are two arms that should take the tape film near the
reading head. I still didn't discover what moves them.

solenoid is not doing its job. It may be weak, a common fault, or the
driver transistor for the solenoid may be open, another common
failure


well... if the solenoid is gone... I think it's a problem. I should get some
copper wire and rebuild the windings inside it (but will it work??!?).
The transistor.. maybe that's a problem too without the schematic of that
monster.
Anyway... if you have experience.. you could tell me someting about the
voltage driving the solenoid.
It has 4 wires upon it: red, orange, yellow and brown.

or crud has got in the well freezing up the solenoid bolt,
not a common problem. I had the manual for this machine somewhere.
I'll try to find it.



I would exclude the crud.. it's really clean inside.
Also the manual would be a great step forward!!

Bye
Daniele

P.S.
Would you continue this topic by email?
you can write me : skrauso (at) infinito . it

--

http://tastiere.altervista.org - THE resource for Synthesizers !
Free patches and sounds



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