How does VCR detects a SVHS tape?

[Rudolf Ladyzhenskii]

Hi, all

I am after a bit of theory. How does VCR dtects that it plays a SVHS tape?
I have JVC HRS5000 on the bench now and it plays all tapes as SVHS. As a
result, normal tapes are played with no color.

I did not have much to do with actual SVHS signal processing.

Any help, links, etc. are appreciated,

Thanks,
Rudolf

 

[Alan Rutlidge]

"Rudolf Ladyzhenskii" <rudolfl@optusnet.com.au> wrote in message
news:3f914434$1$3699$afc38c87@news.optusnet.com.au...

Hi, all

I am after a bit of theory. How does VCR dtects that it plays a SVHS tape?
I have JVC HRS5000 on the bench now and it plays all tapes as SVHS. As a
result, normal tapes are played with no color.

I did not have much to do with actual SVHS signal processing.

Any help, links, etc. are appreciated,

Thanks,
Rudolf

There is a hole in the cassette housing.. Turn the S-VHS cassette upside
down. With the spine label edge towards you you will see a hole on the left
side in the groove. This tells the machine the tape is S-VHS. Probably the
sensor that detects the hole is faulty or the pin that connects to it.

Cheers,
Alan

 

[David Myers]

"RL" == "Rudolf Ladyzhenskii" writes:

RL> Hi, all
RL>
RL> I am after a bit of theory. How does VCR dtects that it plays a
RL> SVHS tape? I have JVC HRS5000 on the bench now and it plays all
RL> tapes as SVHS. As a result, normal tapes are played with no
RL> color.
RL>
RL> I did not have much to do with actual SVHS signal processing.

It uses a rather lo-tech method, a small hole in the case.

Looking at the underneath of the cassette with the tape cover flap
facing away from you, it's on the extreme left about 2cm from the
label. There is a groove or channel that I think is moulded into all
VHS tapes running the entire width of the cassette. The hole is in
that. Compare it with an ordinary VHS tape, you will easily spot it.

***Remove numerals from email address.

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[Rudolf Ladyzhenskii]

Hi,

Thanks,

Switch just tell that tape is SVHS or VHS type. I guess, I should be more
clear in my question. How does VCR detects the type of recording?
SVHS tape can be recorded in SVHS or in VHS. How does VCR tell the
difference? I think, it only uses the switch to allow SVHS recording to be
done only on SVHS tapes.

My problem is that it detects any recording (even ones done on VHS tape) as
SVHS ones. There is a module that detects if tape is SVHS or VHS. Module is
a micro-assembly and I can not read what is written on the IC's there. It
has to be replaced as a whole unit. Before I go ahead and blame this module
(and by the look of it it is a pretty expensive one and probably no longer
available given the age of VCR) I would like to understand how it is
supposed to work.

Thanks,
Rudolf
P.S. If anyone has a scrapped JVC HRS5000 or HRS5500, I would like to buy
this module if pice is right. It is IC301 on video PCB, part number
PB20287A-03

"Alan Rutlidge" <rutlidge*nO-sPaM*@mail.iinet.net.au> wrote in message
news:3f915885$0$23591$5a62ac22@freenews.iinet.net.au...

"Rudolf Ladyzhenskii" <rudolfl@optusnet.com.au> wrote in message
news:3f914434$1$3699$afc38c87@news.optusnet.com.au...
Hi, all

I am after a bit of theory. How does VCR dtects that it plays a SVHS
tape?
I have JVC HRS5000 on the bench now and it plays all tapes as SVHS. As a
result, normal tapes are played with no color.

I did not have much to do with actual SVHS signal processing.

Any help, links, etc. are appreciated,

Thanks,
Rudolf



There is a hole in the cassette housing.. Turn the S-VHS cassette upside
down. With the spine label edge towards you you will see a hole on the
left
side in the groove. This tells the machine the tape is S-VHS. Probably
the
sensor that detects the hole is faulty or the pin that connects to it.

Cheers,
Alan