Any Panasonic VCR Experts In Here?

[Ron]

I have two Panasonic VCR's, model numbers PV-V4540 and PV-9450.

They are almost idenical on the outside and very simular on the
inside.

The "newer" model - PV-V4540 - seems to have a head going bad from
everything I've read.

The PV-9450 works fine, but doesn't have the features that the PV-
V4540 has.

I would like to install the head unit from the PV-9450 (the older one)
in the PV-V4540 (the newer one).

They look the same, but are they the same? And if I swap the
headunits, will the alignment be the same?

Here are pics of the head units. The one thing that I wondering about
is the "arm" on the center post of the (newer) PV-V4540...what is
that?



PV-V4540 head unit
http://i126.photobucket.com/albums/p96/bigelile/IM002417-1.jpg

PV-9450 head unit
http://i126.photobucket.com/albums/p96/bigelile/IM002411-1.jpg

PV-V4540 face
http://i126.photobucket.com/albums/p96/bigelile/IM002414-1.jpg

PV-9450 face
http://i126.photobucket.com/albums/p96/bigelile/IM002413-1.jpg

 

[Arfa Daily]

I have two Panasonic VCR's, model numbers PV-V4540 and PV-9450.

They are almost idenical on the outside and very simular on the
inside.

The "newer" model - PV-V4540 - seems to have a head going bad from
everything I've read.

The PV-9450 works fine, but doesn't have the features that the PV-
V4540 has.

I would like to install the head unit from the PV-9450 (the older one)
in the PV-V4540 (the newer one).

They look the same, but are they the same? And if I swap the
headunits, will the alignment be the same?

Here are pics of the head units. The one thing that I wondering about
is the "arm" on the center post of the (newer) PV-V4540...what is
that?

The arm in the centre is for static discharge. Without it, on a machine
originally fitted with one - which most are - you tend to get little white
dots on the playback picture. Provided the heads *are* exactly the same,
then there are no alignment issues with head swaps on modern VCRs. It is
only two screws, so give it a go. Normally, the screw holes are offset
slightly to make sure that you don't get it on 180 degrees out. At worst, it
just won't work. As a matter of interest, what are the symptoms for your
diagnosis of failing heads on the first one ?

Arfa

 

[N_Cook]

The arm in the centre is for static discharge. Without it, on a machine
originally fitted with one - which most are - you tend to get little white
dots on the playback picture. Provided the heads *are* exactly the same,
then there are no alignment issues with head swaps on modern VCRs. It is
only two screws, so give it a go. Normally, the screw holes are offset
slightly to make sure that you don't get it on 180 degrees out. At worst, it
just won't work. As a matter of interest, what are the symptoms for your
diagnosis of failing heads on the first one ?

Arfa

A child's plastic "toy" microscope of x20 or x30 magnification. Just the
barrel is useful for inspecting with part of the objective end ground down
at an angle, back to (or even into ) the lens, allows to get close enough
for video heads to inspect, in situ , when illuminated with a torch. To
inspect whether the gap is chipped and generally whether worn down too much.
View in a downwards sense wherever there is enough clearance.

 

[Arfa Daily]

from the parts list pvv4540 uses the beliow listed upper cylinder head
VEGS0427 ( A )
VEGS0428 ( B,C,D )
VEGS0429 ( E,F )

pv9450 uses
VEHS0571 ( A )
VEHS0570 ( B,C )
VEHS0567 ( D,E )
not much help but swapping may not hurt

Given that info, it's probably not going to work right. Hifi sound is
critical of correct head performance, so if there are any specification
differences between the head drums, there will likely be a problem. As far
as swapping the entire head drum assembly goes, you will often find that
even identical-looking assemblies won't fit because a screw hole or chassis
locating boss has been deliberately offset to prevent it. As for having to
use a puller to remove the upper head drum (which I have always thought is a
far more straightforward job than swapping the whole assembly) on some
machines, that used to be a given, but I always found that Pans came off ok.

Not that for some years it's been a viable proposition to replace heads,
even on 'good' machines. The cost of the head drum alone, without any
labour, exceeded tha cost of a bargain warehouse all singing and dancing
machine with a shiny new 2 year warranty ...

Arfa

 

[Ron]

The arm in the centre is for static discharge. Without it, on a machine
originally fitted with one - which most are - you tend to get little white
dots on the playback picture. Provided the heads *are* exactly the same,
then there are no alignment issues with head swaps on modern VCRs. It is
only two screws, so give it a go. Normally, the screw holes are offset
slightly to make sure that you don't get it on 180 degrees out. At worst,it
just won't work. As a matter of interest, what are the symptoms for your
diagnosis of failing heads on the first one ?

Arfa

When the video starts to get noticeably bad a screen will pop-up that
says the heads need to be cleaned. So for yrs I've been taking the top
off and cleaning the heads when the screen appears. (white piece of
paper with rubbing alcohol holding it against the heads on the upper
drum while turning it counterclockwise - alcohol and Q Tips for the
erase and audio heads) Put the top back on and everything is great
until they get dirty again.

So earlier this week the picture started looking *really* bad, and
sure enough there is the screen telling me the heads are dirty...so I
do my usual procedure, only this time, the picture still looks like
crap. The warning screen isn't coming up, but previously recorded
tapes in EP mode look horrible, any tapes I make in EP mode look
horrible.

Tapes that I've previously made in SP mode look OK and store bought
movies look OK also. Not great, just OK. (Same with making a tape in
SP)

Before any of this happened, while watching a recorded EP mode tape if
I were to hit rewind to back up the tape, about 25% of the upper
screen was nothing but noise lines/snow.

But, this would only happen if it was near the beginning of the tape.
Once you got past a certain point (3/8ths - 1/2 way) this problem
would go away.

After cleaning the heads, this problem is still present. I can fix
that problem by adjusting (big adjustment 1/4 turn) the feed side
roller guide, but the picture still looks horrible.

So, after reading many articles, I can only come to the conclusion
that one of the 4 heads in the drum/cylinder went bad.

I haven't had time to switch the heads yet, when I do I will post the
results.

Meatplow, after removing the 2 small screws, the upper part of the
drum/cylinder, what ever you wanna call it, just lifts right off.

 

[Ron]

   That is the upper and lower drums, spindle motor and the head
electronics. Unscrew it from the chassis, unplug the cables and change
the whole assembly.

   That is how heads are changed on R-R broadcast tape machines, like
the 1" Sony machines we used at Ch. 55 in Orlando. If you were used to
it, you could drop a new $1100 head into the machine in under 15
minutes, and be back in service.  It came prealigned and tested.  You
didn't have to take the machine out of the rack or unhook anything else.
It was one of the things I liked about Sony Broadcast Electronics..

Orlando huh? Wanna help out a neighbor?

 

[Ron]

Given that info, it's probably not going to work right. Hifi sound is
critical of correct head performance, so if there are any specification
differences between the head drums, there will likely be a problem.

Well, that is an understatement.

Put the head drum from the older working VCR into the newer one, there
was no signal on the face plate for "HiFi".

So I put it back into the - what was working unit - and NO HiIFi.

Don't know what happened, but the newer VCR fried something in the
older ones head drum.

Now I have 2 Panasonics that don't work.

 

[Ron]

   I would, but I'm closer to Gainesville these days.  Orlando was 20+
years ago, and I've slowly moved North since then.

Ha, that was about how many yrs ago I moved here.

What a traffic nightmare this place has become since then.

Used to be only I-4, now it's every major road.

 

[Arfa Daily]

The arm in the centre is for static discharge. Without it, on a machine
originally fitted with one - which most are - you tend to get little white
dots on the playback picture. Provided the heads *are* exactly the same,
then there are no alignment issues with head swaps on modern VCRs. It is
only two screws, so give it a go. Normally, the screw holes are offset
slightly to make sure that you don't get it on 180 degrees out. At worst,
it
just won't work. As a matter of interest, what are the symptoms for your
diagnosis of failing heads on the first one ?

Arfa

When the video starts to get noticeably bad a screen will pop-up that
says the heads need to be cleaned. So for yrs I've been taking the top
off and cleaning the heads when the screen appears. (white piece of
paper with rubbing alcohol holding it against the heads on the upper
drum while turning it counterclockwise - alcohol and Q Tips for the
erase and audio heads) Put the top back on and everything is great
until they get dirty again.

So earlier this week the picture started looking *really* bad, and
sure enough there is the screen telling me the heads are dirty...so I
do my usual procedure, only this time, the picture still looks like
crap. The warning screen isn't coming up, but previously recorded
tapes in EP mode look horrible, any tapes I make in EP mode look
horrible.

Tapes that I've previously made in SP mode look OK and store bought
movies look OK also. Not great, just OK. (Same with making a tape in
SP)

Before any of this happened, while watching a recorded EP mode tape if
I were to hit rewind to back up the tape, about 25% of the upper
screen was nothing but noise lines/snow.

But, this would only happen if it was near the beginning of the tape.
Once you got past a certain point (3/8ths - 1/2 way) this problem
would go away.

After cleaning the heads, this problem is still present. I can fix
that problem by adjusting (big adjustment 1/4 turn) the feed side
roller guide, but the picture still looks horrible.

So, after reading many articles, I can only come to the conclusion
that one of the 4 heads in the drum/cylinder went bad.

I haven't had time to switch the heads yet, when I do I will post the
results.

Meatplow, after removing the 2 small screws, the upper part of the
drum/cylinder, what ever you wanna call it, just lifts right off.



Yes, that is normally the case with Pans. Sounds as though one of the heads
may have become chipped, but it is also possible that one of them has become
badly blocked. Sometimes when that is the case, it's necessary to get a bit
vicious with it. A trick that was shown to me by a manufacturer's service
course lecturer, is to hold a fingernail against a running tape, as it is
around the head drum - so that you can feel the heads going "DRRRRRRRRR"
against your nail, through the tape, if you see what I mean. It is amazing
how quickly and how well this recovers a head that has become badly clogged
from a tape that is moist from condensation, or is shedding oxide. It has
got me out of trouble on many occasions.

Arfa

 

[Arfa Daily]

Given that info, it's probably not going to work right. Hifi sound is
critical of correct head performance, so if there are any specification
differences between the head drums, there will likely be a problem.

Well, that is an understatement.

Put the head drum from the older working VCR into the newer one, there
was no signal on the face plate for "HiFi".

So I put it back into the - what was working unit - and NO HiIFi.

Don't know what happened, but the newer VCR fried something in the
older ones head drum.

Now I have 2 Panasonics that don't work.



I feel that to be highly unlikely, as the coupling between the heads and the
amplification electronics is completely isolated by a rotary transformer,
the primary of which is in the upper head drum, and the secondary, in the
lower.

Far more likely is that the screw-holes are not offset, and you have managed
to get the upper drums 180 degrees out on the centre spindle. Unscrew the
formerly good one again, and try turning it through 180 degrees, and see if
the holes still line up. If they do, screw it down again, and retest. If
that gets you back to working, then try your swap again, taking note of the
same potential problem.

Arfa

 

[Ron]

Well, that is an understatement.

Put the head drum from the older working VCR into the newer one, there
was no signal on the face plate for "HiFi".

So I put it back into the - what was working unit - and NO HiIFi.

Don't know what happened, but the newer VCR fried something in the
older ones head drum.

Now I have 2 Panasonics that don't work.

I feel that to be highly unlikely, as the coupling between the heads and the
amplification electronics is completely isolated by a rotary transformer,
the primary of which is in the upper head drum, and the secondary, in the
lower.

Far more likely is that the screw-holes are not offset, and you have managed
to get the upper drums 180 degrees out on the centre spindle. Unscrew the
formerly good one again, and try turning it through 180 degrees, and see if
the holes still line up. If they do, screw it down again, and retest. If
that gets you back to working, then try your swap again, taking note of the
same potential problem.

Arfa

The upper drum(s) can only go on one way. It has a pilot hole for a
guide and the screw holes are also slightly offset.

Don't know what happened, but switching them fried something in either
the units themselves, or in the upper drums.

*Both* units with their original heads have video, but the audio is
muddy. I cleaned both using the fingernail method you mentioned,
followed up with paper and alcohol, no change.

Oh well.........

 

[Ron]

Didnt the fact that they were two completely different model numbers on the
heads and drums tip you off?

Just because something has a different model number, doesn't mean it
won't work.

Sometimes the same product can have an updated model number.

That was the reason for my "Any Panasonic VCR Experts In Here?".....I
took a chance, and it didn't work out.....oh well.

Instead of criticizing what I did, give me an answer as to why it
didn't work...besides they weren't the same model number.

 

[Arfa Daily]

The upper drum(s) can only go on one way. It has a pilot hole for a
guide and the screw holes are also slightly offset.

Don't know what happened, but switching them fried something in either
the units themselves, or in the upper drums.

*Both* units with their original heads have video, but the audio is
muddy. I cleaned both using the fingernail method you mentioned,
followed up with paper and alcohol, no change.

Oh well.........

OK. Well the offsetting of the screw holes is what I had expected, so I
really don't know what you can have done. I can't think of any way that
either set of heads, let alone both, can have been damaged by simply
swapping them between machines. Even if one set had much more 'robust'
windings to take a higher bias current on record, they should at least have
survived in the other machine. It's been a while since I did much work on
VCRs as they have not been popular here for a couple of years now, but
'muddy' is not a description that I would normally have found a way of
putting to a hifi sound track. Usually, this track has a tendency to drop
out completely when the heads wear, and the machine reverts back to the
linear sound track, which can be muddy if the A/S head is not properly
aligned. You said before that you had altered the setting of the supply
guide roller. Have you tried making sure that you have that back in exactly
the right place ? As I think I pointed out earlier, correct recovery of the
hifi sound track is critical of several factors.

Arfa

 

[Ron]

OK. Well the offsetting of the screw holes is what I had expected, so I
really don't know what you can have done. I can't think of any way that
either set of heads, let alone both, can have been damaged by simply
swapping them between machines. Even if one set had much more 'robust'
windings to take a higher bias current on record, they should at least have
survived in the other machine. It's been a while since I did much work on
VCRs as they have not been popular here for a couple of years now, but
'muddy' is not a description that I would normally have found a way of
putting to a hifi sound track. Usually, this track has a tendency to drop
out completely when the heads wear, and the machine reverts back to the
linear sound track, which can be muddy if the A/S head is not properly
aligned. You said before that you had altered the setting of the supply
guide roller. Have you tried making sure that you have that back in exactly
the right place ? As I think I pointed out earlier, correct recovery of the
hifi sound track is critical of several factors.

Arfa

I never touched the roller guides on the older VCR that worked fine.
All I did was remove the upper drum (or whatever it's called) and
install it on my "newer" Panasonic.

There was no HiFi audio icon on the newer unit with the older drum
unit.

So, I removed it, and reinstalled it on in the unit it came from and I
now have muddy/humming audio.

And vice-versa.

 

[Ron]

I am sorry it didnt work out for you. Keep looking around at salvation army or
thrift stores and you might find another one of those models. I see panasonics
at the local Deseret Industries thrift stores all the time for $5.

That is my plan. Salvation Army, Goodwill, Craigslist, etc.

 

[Andy Cuffe]

That is my plan. Salvation Army, Goodwill, Craigslist, etc.

About the only thing that could have gone wrong is that one of the
hi-fi heads got damaged while you were swapping them. It's easy to
bump one of the heads and break it. Did you try cleaning the heads
after the swap? Did it at least fix the video problem?

There's a slight chance that you need to adjust the head switching
point. It was very critical on older hi-fi VCRs. Just removing and
replacing the same head drum can be enough to throw it off. I don't
know if newer Panasonics require an adjustment.

I've found that video heads will usually work fine if they physically
fit, and have the same number of heads.

In a few rare cases, heads from different manufacturers can even be
swapped. For example, in the 80's and early 90's Goldstar copied
Panasonic's head mounting and electrical connections exactly. I fixed
many Panasonics with heads salvaged from Goldstar VCRs. It worked out
well because Panasonic VCRs lasted a long time and often had worn out
heads. On the other hand, Goldstar VCRs usually broke long before the
heads had any wear on them.
Andy Cuffe

[email protected]

 

[Arfa Daily]

About the only thing that could have gone wrong is that one of the
hi-fi heads got damaged while you were swapping them. It's easy to
bump one of the heads and break it. Did you try cleaning the heads
after the swap? Did it at least fix the video problem?

There's a slight chance that you need to adjust the head switching
point. It was very critical on older hi-fi VCRs. Just removing and
replacing the same head drum can be enough to throw it off. I don't
know if newer Panasonics require an adjustment.

I've found that video heads will usually work fine if they physically
fit, and have the same number of heads.

In a few rare cases, heads from different manufacturers can even be
swapped. For example, in the 80's and early 90's Goldstar copied
Panasonic's head mounting and electrical connections exactly. I fixed
many Panasonics with heads salvaged from Goldstar VCRs. It worked out
well because Panasonic VCRs lasted a long time and often had worn out
heads. On the other hand, Goldstar VCRs usually broke long before the
heads had any wear on them.
Andy Cuffe

[email protected]

My feelings and experience too, Andy. I really can't figure what he did
wrong or what happened to bring the situation to the point of neither
machine working.

Arfa

 

[Ron]

About the only thing that could have gone wrong is that one of the
hi-fi heads got damaged while you were swapping them.  It's easy to
bump one of the heads and break it.  Did you try cleaning the heads
after the swap?  Did it at least fix the video problem?

Didn't bump the drum/head on anything. Had the VCR's sitting side-by-
side. 4 screws, doesn't get any easier. And the heads were cleaned
after the swap, before I even put a tape in.

The video problem still remains on the newer unit, plus it now has the
audio problem. The older unit has a fine picture, but it now has the
*same* audio problem. (very muddy and choppy while playing in HiFi.)

There's a slight chance that you need to adjust the head switching
point.  It was very critical on older hi-fi VCRs.  Just removing and
replacing the same head drum can be enough to throw it off.  I don't
know if newer Panasonics require an adjustment.

Is that something I can do with no special eqt?

I've found that video heads will usually work fine if they physically
fit, and have the same number of heads.  

I don't see why it wouldn't work, then again, I'm not a VCR
repairman.

It's not a huge deal now, last Saturday I found a BRAND NEW Sony SLV-
N55 (a better VCR anyway) for $8.00 at a Salvation Army! But, it would
be nice if I could resolve the audio problem on the older Panasonic,
if possible.