Anybody got a copy of the schematic that's in the back of the user guide
that they can scan for me, please ? I've searched all my files and drawers
high and low, and can't find my book anywhere ... I thought that the 'net
would be awash with copies of the schematic, but it seems only for the Mk 2,
which is totally different to the MK 4.

TIA

Arfa

Arfa Daily wrote:
Anybody got a copy of the schematic that's in the back of the user
guide that they can scan for me, please ? I've searched all my files
and drawers high and low, and can't find my book anywhere ... I
thought that the 'net would be awash with copies of the schematic,
but it seems only for the Mk 2, which is totally different to the MK
4.
TIA

Is it the circuit diagram at
http://www.radiomuseum.org/r/avo_uni...er_8_mk_i.html ?
(Registration necessary for download. I have not done it as mine's a Mk
II.)
--
Robin
PM may be sent to rbw0{at}hotmail{dot}com

"Robin" wrote in message
...
Arfa Daily wrote:
Anybody got a copy of the schematic that's in the back of the user
guide that they can scan for me, please ? I've searched all my files
and drawers high and low, and can't find my book anywhere ... I
thought that the 'net would be awash with copies of the schematic,
but it seems only for the Mk 2, which is totally different to the MK
4.
TIA

Is it the circuit diagram at
http://www.radiomuseum.org/r/avo_uni...er_8_mk_i.html ?
(Registration necessary for download. I have not done it as mine's a Mk
II.)
--
Robin
PM may be sent to rbw0{at}hotmail{dot}com


Hi Robin, thanks for that. It would appear to be the correct one. Looks as
though you need to pay to become a member, so I will hold off for now until
all the feelers that I have out, run dry. It's really annoying because I
have owned the meter from new when I was an apprentice, and I have the book,
which has the schematic in it, carefully filed away somewhere, but I'm
buggered if I can now find it. It is in a box file, but said boxfile is not
where I know it should be. Even more annoying is that I have damaged the
meter by my own stupidity, so now have the need to fix it ... :-(

Arfa

"Arfa Daily" wrote in message
...


"Robin" wrote in message
...
Arfa Daily wrote:
Anybody got a copy of the schematic that's in the back of the user
guide that they can scan for me, please ? I've searched all my files
and drawers high and low, and can't find my book anywhere ... I
thought that the 'net would be awash with copies of the schematic,
but it seems only for the Mk 2, which is totally different to the MK
4.
TIA

Is it the circuit diagram at
http://www.radiomuseum.org/r/avo_uni...er_8_mk_i.html ?
(Registration necessary for download. I have not done it as mine's a Mk
II.)
--
Robin
PM may be sent to rbw0{at}hotmail{dot}com


Hi Robin, thanks for that. It would appear to be the correct one. Looks as
though you need to pay to become a member, so I will hold off for now
until all the feelers that I have out, run dry. It's really annoying
because I have owned the meter from new when I was an apprentice, and I
have the book, which has the schematic in it, carefully filed away
somewhere, but I'm buggered if I can now find it. It is in a box file, but
said boxfile is not where I know it should be. Even more annoying is that
I have damaged the meter by my own stupidity, so now have the need to fix
it ... :-(

There may be an outside chance its turned up on
alt.binaries.e-book.technical at some time or other.

Whether I'd have downloaded it is another matter, and it would take a while
to search my archives.

You could try a REQ: on that group while I try to remember where I put all
the unsorted stuff.

On Fri, 01 Apr 2011 21:46:53 +0100, Arfa Daily wrote:

"Robin" wrote in message
...
Arfa Daily wrote:
Anybody got a copy of the schematic that's in the back of the user
guide that they can scan for me, please ? I've searched all my files
and drawers high and low, and can't find my book anywhere ... I
thought that the 'net would be awash with copies of the schematic, but
it seems only for the Mk 2, which is totally different to the MK 4.
TIA

Is it the circuit diagram at
http://www.radiomuseum.org/r/avo_uni...er_8_mk_i.html ?
(Registration necessary for download. I have not done it as mine's a
Mk II.)
--
Robin
PM may be sent to rbw0{at}hotmail{dot}com


Hi Robin, thanks for that. It would appear to be the correct one. Looks
as though you need to pay to become a member, so I will hold off for now
until all the feelers that I have out, run dry. It's really annoying
because I have owned the meter from new when I was an apprentice, and I
have the book, which has the schematic in it, carefully filed away
somewhere, but I'm buggered if I can now find it. It is in a box file,
but said boxfile is not where I know it should be. Even more annoying is
that I have damaged the meter by my own stupidity, so now have the need
to fix it ... :-(

Arfa

That's too bad. I have some old gear I used as an apprentice that have a
high value in the nostalgia department. An old EICO 232 VTVM, B&K 1801
freq. counter, Beckman Tech 310 DVM, Amprobe Amp Clamp and some other
things that I can't think of right now.



--
Live Fast Die Young, Leave A Pretty Corpse

Arfa Daily wrote:


"Robin" wrote in message
...
Arfa Daily wrote:
Anybody got a copy of the schematic that's in the back of the user
guide that they can scan for me, please ? I've searched all my files
and drawers high and low, and can't find my book anywhere ... I
thought that the 'net would be awash with copies of the schematic,
but it seems only for the Mk 2, which is totally different to the MK
4.
TIA

Is it the circuit diagram at
http://www.radiomuseum.org/r/avo_uni...er_8_mk_i.html ?
(Registration necessary for download. I have not done it as mine's a
Mk II.)
--
Robin
PM may be sent to rbw0{at}hotmail{dot}com


Hi Robin, thanks for that. It would appear to be the correct one. Looks
as though you need to pay to become a member, so I will hold off for now
until all the feelers that I have out, run dry. It's really annoying
because I have owned the meter from new when I was an apprentice, and I
have the book, which has the schematic in it, carefully filed away
somewhere, but I'm buggered if I can now find it. It is in a box file,
but said boxfile is not where I know it should be. Even more annoying is
that I have damaged the meter by my own stupidity, so now have the need
to fix it ... :-(

Have you tried:-

http://www.megger.com/eu/index.php

And get a log on for the support pages?

They seem to be the sort of company who do product support properly. It
might even be worth giving them a call at their head office in Dover.

--
Tciao for Now!

John.

In message on Fri, 1 Apr 2011 16:45:37 +0100
Arfa Daily wrote:

Anybody got a copy of the schematic that's in the back of the user guide
that they can scan for me, please ? I've searched all my files and drawers
high and low, and can't find my book anywhere ... I thought that the 'net
would be awash with copies of the schematic, but it seems only for the Mk 2,
which is totally different to the MK 4.


Have you tried the Vintage Radio Forum?

http://www.vintage-radio.net/forum/index.php

They have a vintage test equipment forum and there are lots of nice, helpful
people on there ...

On the other hand, there's also me ...

--

Terry

In article , Arfa Daily
writes

Even more annoying is that I have damaged the
meter by my own stupidity

Measured the resistance of the mains?

BTDTGTTS.

--
(\__/)
(='.'=)
(")_(")

Arfa Daily wrote:
"Robin" wrote in message
...
Arfa Daily wrote:
Anybody got a copy of the schematic that's in the back of the user
guide that they can scan for me, please ? I've searched all my files
and drawers high and low, and can't find my book anywhere ... I
thought that the 'net would be awash with copies of the schematic,
but it seems only for the Mk 2, which is totally different to the MK
4.
TIA

Is it the circuit diagram at
http://www.radiomuseum.org/r/avo_uni...er_8_mk_i.html ?
(Registration necessary for download. I have not done it as mine's
a Mk II.)
--
Robin
PM may be sent to rbw0{at}hotmail{dot}com


Hi Robin, thanks for that. It would appear to be the correct one.
Looks as though you need to pay to become a member, so I will hold
off for now until all the feelers that I have out, run dry. It's
really annoying because I have owned the meter from new when I was an
apprentice, and I have the book, which has the schematic in it,
carefully filed away somewhere, but I'm buggered if I can now find
it. It is in a box file, but said boxfile is not where I know it
should be. Even more annoying is that I have damaged the meter by my
own stupidity, so now have the need to fix it ... :-(

**I can't help you, but I do know that AVOs are bloody hard to damage. You
must have put considerable effort into it.


--
Trevor Wilson
www.rageaudio.com.au

In article ,
Arfa Daily wrote:
Anybody got a copy of the schematic that's in the back of the user guide
that they can scan for me, please ? I've searched all my files and
drawers high and low, and can't find my book anywhere ... I thought
that the 'net would be awash with copies of the schematic, but it seems
only for the Mk 2, which is totally different to the MK 4.

Have you tried AVO direct? They still make the Model 8, IIRC.

--
*Dance like nobody's watching.

Dave Plowman London SW
To e-mail, change noise into sound.

On Apr 1, 11:53*pm, "Trevor Wilson" wrote:

**I can't help you, but I do know that AVOs are bloody hard to damage. You
must have put considerable effort into it.

Not that hard. The overload cutout is a sensitive beast and the
adjustment procedure is a little convoluted.

"Dave Plowman (News)" wrote in message
...
In article ,
Arfa Daily wrote:
Anybody got a copy of the schematic that's in the back of the user guide
that they can scan for me, please ? I've searched all my files and
drawers high and low, and can't find my book anywhere ... I thought
that the 'net would be awash with copies of the schematic, but it seems
only for the Mk 2, which is totally different to the MK 4.

Have you tried AVO direct? They still make the Model 8, IIRC.

--
*Dance like nobody's watching.

Dave Plowman London SW
To e-mail, change noise into sound.

Thanks all. Some useful suggestions there. You are of course all quite
correct in that it is very difficult to damage an AVO. This one is now
around 40 years old, and it has been in use on a daily basis for all of
those years, and has withstood much normal workshop abuse - yes, including
measuring the resistance of the mains ! - many times over. It was a very
high pulse voltage that caused the problem that I now have. I have recently
been working on some pro lighting equipment that makes use of short-arc
discharge lamps, and it is important that the running voltage, once they
have struck, is correct. They are fed with a 50% duty factor square wave at
about 200v p-p, resulting in an average 'AC' voltage of 100V across the
lamp. The AVO reads this nicely on either its 100V or 250V AC ranges. When
the lamp is being started, however, it is subjected to a pulsed igniter
voltage of several kV. When the lamp strikes, its impedance drops quite low,
and this swamps the igniter circuit and stops it. Stupidly, I had the meter
connected during the ignition sequence, and now, 100V of 'real' sinusoidal
AC reads about 35V ...

I am at this point thinking that it is going to be one of the two rectifier
diodes, which seem to be "OA" germanium types, but I guess it could also be
a fried metal film precision resistor. Needless to say, there is no visible
evidence of any problem :-\

Arfa

Dave Plowman (News) used his keyboard to write :
In article ,
Arfa Daily wrote:
Anybody got a copy of the schematic that's in the back of the user guide
that they can scan for me, please ? I've searched all my files and
drawers high and low, and can't find my book anywhere ... I thought
that the 'net would be awash with copies of the schematic, but it seems
only for the Mk 2, which is totally different to the MK 4.

Have you tried AVO direct? They still make the Model 8, IIRC.

They stopped making it about, oh - two or three years ago. I think too
expensive, too complex to make were the reasons quoted.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Harry Bloomfield wrote:
Dave Plowman (News) used his keyboard to write :
In article ,
Arfa Daily wrote:
Anybody got a copy of the schematic that's in the back of the user guide
that they can scan for me, please ? I've searched all my files and
drawers high and low, and can't find my book anywhere ... I thought
that the 'net would be awash with copies of the schematic, but it seems
only for the Mk 2, which is totally different to the MK 4.

Have you tried AVO direct? They still make the Model 8, IIRC.

They stopped making it about, oh - two or three years ago. I think too
expensive, too complex to make were the reasons quoted.

The last one came off the line in November 2008. This gave rise to
simultaneous nostalgia and relief that reference quality meters now
weighed less than a sack of coal. ;-)

--
Tciao for Now!

John.

"Ian Field" wrote in message
...

"Arfa Daily" wrote in message
...


"Robin" wrote in message
...
Arfa Daily wrote:
Anybody got a copy of the schematic that's in the back of the user
guide that they can scan for me, please ? I've searched all my files
and drawers high and low, and can't find my book anywhere ... I
thought that the 'net would be awash with copies of the schematic,
but it seems only for the Mk 2, which is totally different to the MK
4.
TIA

Is it the circuit diagram at
http://www.radiomuseum.org/r/avo_uni...er_8_mk_i.html ?
(Registration necessary for download. I have not done it as mine's a Mk
II.)
--
Robin
PM may be sent to rbw0{at}hotmail{dot}com


Hi Robin, thanks for that. It would appear to be the correct one. Looks
as though you need to pay to become a member, so I will hold off for now
until all the feelers that I have out, run dry. It's really annoying
because I have owned the meter from new when I was an apprentice, and I
have the book, which has the schematic in it, carefully filed away
somewhere, but I'm buggered if I can now find it. It is in a box file,
but said boxfile is not where I know it should be. Even more annoying is
that I have damaged the meter by my own stupidity, so now have the need
to fix it ... :-(

There may be an outside chance its turned up on
alt.binaries.e-book.technical at some time or other.

Whether I'd have downloaded it is another matter, and it would take a
while to search my archives.

You could try a REQ: on that group while I try to remember where I put all
the unsorted stuff.


Thanks Ian. Be appreciated if you were able to have a quick look. Wouldn't
have been a problem back in our old TeleMag days. John would have flung an
ad in "Help Wanted" for me ... :-)

Arfa

"Meat Plow" wrote in message
news
On Fri, 01 Apr 2011 21:46:53 +0100, Arfa Daily wrote:

"Robin" wrote in message
...
Arfa Daily wrote:
Anybody got a copy of the schematic that's in the back of the user
guide that they can scan for me, please ? I've searched all my files
and drawers high and low, and can't find my book anywhere ... I
thought that the 'net would be awash with copies of the schematic, but
it seems only for the Mk 2, which is totally different to the MK 4.
TIA

Is it the circuit diagram at
http://www.radiomuseum.org/r/avo_uni...er_8_mk_i.html ?
(Registration necessary for download. I have not done it as mine's a
Mk II.)
--
Robin
PM may be sent to rbw0{at}hotmail{dot}com


Hi Robin, thanks for that. It would appear to be the correct one. Looks
as though you need to pay to become a member, so I will hold off for now
until all the feelers that I have out, run dry. It's really annoying
because I have owned the meter from new when I was an apprentice, and I
have the book, which has the schematic in it, carefully filed away
somewhere, but I'm buggered if I can now find it. It is in a box file,
but said boxfile is not where I know it should be. Even more annoying is
that I have damaged the meter by my own stupidity, so now have the need
to fix it ... :-(

Arfa

That's too bad. I have some old gear I used as an apprentice that have a
high value in the nostalgia department. An old EICO 232 VTVM, B&K 1801
freq. counter, Beckman Tech 310 DVM, Amprobe Amp Clamp and some other
things that I can't think of right now.




Yes, Meat. It's very frustrating. I cut my 'professional' teeth with that
meter, and it has served me faithfully over the years without serious
mishap. It is still in weekly use, but not quite the daily use that it once
was. For some types of repair, the swinging needle of a quality instrument
like this, is so much more appropriate than a digital type ...

Arfa
--

Arfa Daily wrote:


"Meat Plow" wrote in message
news
On Fri, 01 Apr 2011 21:46:53 +0100, Arfa Daily wrote:

"Robin" wrote in message
...
Arfa Daily wrote:
Anybody got a copy of the schematic that's in the back of the user
guide that they can scan for me, please ? I've searched all my files
and drawers high and low, and can't find my book anywhere ... I
thought that the 'net would be awash with copies of the schematic, but
it seems only for the Mk 2, which is totally different to the MK 4.
TIA

Is it the circuit diagram at
http://www.radiomuseum.org/r/avo_uni...er_8_mk_i.html ?
(Registration necessary for download. I have not done it as mine's a
Mk II.)
--
Robin
PM may be sent to rbw0{at}hotmail{dot}com


Hi Robin, thanks for that. It would appear to be the correct one. Looks
as though you need to pay to become a member, so I will hold off for now
until all the feelers that I have out, run dry. It's really annoying
because I have owned the meter from new when I was an apprentice, and I
have the book, which has the schematic in it, carefully filed away
somewhere, but I'm buggered if I can now find it. It is in a box file,
but said boxfile is not where I know it should be. Even more annoying is
that I have damaged the meter by my own stupidity, so now have the need
to fix it ... :-(

Arfa

That's too bad. I have some old gear I used as an apprentice that have a
high value in the nostalgia department. An old EICO 232 VTVM, B&K 1801
freq. counter, Beckman Tech 310 DVM, Amprobe Amp Clamp and some other
things that I can't think of right now.




Yes, Meat. It's very frustrating. I cut my 'professional' teeth with
that meter, and it has served me faithfully over the years without
serious mishap. It is still in weekly use, but not quite the daily use
that it once was. For some types of repair, the swinging needle of a
quality instrument like this, is so much more appropriate than a digital
type ...


Its a well known fact that the human eye can gain a rough ideas of
what's going on much faster with an analogue display, as it takes longer
to read a digital display, although in the end that is more accurate.

I have never felt the need for a DVM or DAM..99.99% of voltage and
current readings are of the 'is it within 20% of where it should be'
flavour.

The fact is an LCD meter is CHEAPER than a quality moving needle display.

Not better.

Arfa
--

"The Natural Philosopher" wrote in message
...
Arfa Daily wrote:


"Meat Plow" wrote in message
news
On Fri, 01 Apr 2011 21:46:53 +0100, Arfa Daily wrote:

"Robin" wrote in message
...
Arfa Daily wrote:
Anybody got a copy of the schematic that's in the back of the user
guide that they can scan for me, please ? I've searched all my files
and drawers high and low, and can't find my book anywhere ... I
thought that the 'net would be awash with copies of the schematic,
but
it seems only for the Mk 2, which is totally different to the MK 4.
TIA

Is it the circuit diagram at
http://www.radiomuseum.org/r/avo_uni...er_8_mk_i.html ?
(Registration necessary for download. I have not done it as mine's a
Mk II.)
--
Robin
PM may be sent to rbw0{at}hotmail{dot}com


Hi Robin, thanks for that. It would appear to be the correct one. Looks
as though you need to pay to become a member, so I will hold off for
now
until all the feelers that I have out, run dry. It's really annoying
because I have owned the meter from new when I was an apprentice, and I
have the book, which has the schematic in it, carefully filed away
somewhere, but I'm buggered if I can now find it. It is in a box file,
but said boxfile is not where I know it should be. Even more annoying
is
that I have damaged the meter by my own stupidity, so now have the need
to fix it ... :-(

Arfa

That's too bad. I have some old gear I used as an apprentice that have a
high value in the nostalgia department. An old EICO 232 VTVM, B&K 1801
freq. counter, Beckman Tech 310 DVM, Amprobe Amp Clamp and some other
things that I can't think of right now.




Yes, Meat. It's very frustrating. I cut my 'professional' teeth with that
meter, and it has served me faithfully over the years without serious
mishap. It is still in weekly use, but not quite the daily use that it
once was. For some types of repair, the swinging needle of a quality
instrument like this, is so much more appropriate than a digital type ...


Its a well known fact that the human eye can gain a rough ideas of what's
going on much faster with an analogue display, as it takes longer to read
a digital display, although in the end that is more accurate.

I have never felt the need for a DVM or DAM..99.99% of voltage and current
readings are of the 'is it within 20% of where it should be' flavour.

The fact is an LCD meter is CHEAPER than a quality moving needle display.

Not better.


Yes, agreed on all points ...

Arfa

In article ,
The Natural Philosopher wrote:
The fact is an LCD meter is CHEAPER than a quality moving needle display.

Not better.

You'd have to have a lot of ranges on a 'needle' display to give anywhere
near the accuracy of a 3 quid DVM. They're also far more difficult to read
accurately. But for seeing the direction and rate of change of some things
can be useful.

My AVO 8 - also bought when I started work - stays on the shelf.

--
*Sometimes I wake up grumpy; Other times I let him sleep.

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Harry Bloomfield wrote:
Have you tried AVO direct? They still make the Model 8, IIRC.

They stopped making it about, oh - two or three years ago. I think too
expensive, too complex to make were the reasons quoted.

They were certainly very expensive last time I saw them for sale - about
700 quid? So most probably just bought for a museum or display purposes.

--
*Could it be that "I do " is the longest sentence? *

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Plowman (News) wrote:
In article ,
The Natural Philosopher wrote:
The fact is an LCD meter is CHEAPER than a quality moving needle display.

Not better.

You'd have to have a lot of ranges on a 'needle' display to give anywhere
near the accuracy of a 3 quid DVM.

Who wants the accuracy?

And they DO come equipped with lots of rangers.

They're also far more difficult to read
accurately.

Which is seldom necessary.

But for seeing the direction and rate of change of some things
can be useful.

My AVO 8 - also bought when I started work - stays on the shelf.

On Sat, 02 Apr 2011 10:59:02 +0100, The Natural Philosopher wrote:

Arfa Daily wrote:


"Meat Plow" wrote in message
news
On Fri, 01 Apr 2011 21:46:53 +0100, Arfa Daily wrote:

"Robin" wrote in message
...
Arfa Daily wrote:
Anybody got a copy of the schematic that's in the back of the user
guide that they can scan for me, please ? I've searched all my
files and drawers high and low, and can't find my book anywhere ...
I thought that the 'net would be awash with copies of the
schematic, but it seems only for the Mk 2, which is totally
different to the MK 4. TIA

Is it the circuit diagram at
http://www.radiomuseum.org/r/avo_uni...er_8_mk_i.html ?
(Registration necessary for download. I have not done it as mine's
a Mk II.)
--
Robin
PM may be sent to rbw0{at}hotmail{dot}com


Hi Robin, thanks for that. It would appear to be the correct one.
Looks as though you need to pay to become a member, so I will hold
off for now until all the feelers that I have out, run dry. It's
really annoying because I have owned the meter from new when I was an
apprentice, and I have the book, which has the schematic in it,
carefully filed away somewhere, but I'm buggered if I can now find
it. It is in a box file, but said boxfile is not where I know it
should be. Even more annoying is that I have damaged the meter by my
own stupidity, so now have the need to fix it ... :-(

Arfa

That's too bad. I have some old gear I used as an apprentice that have
a high value in the nostalgia department. An old EICO 232 VTVM, B&K
1801 freq. counter, Beckman Tech 310 DVM, Amprobe Amp Clamp and some
other things that I can't think of right now.




Yes, Meat. It's very frustrating. I cut my 'professional' teeth with
that meter, and it has served me faithfully over the years without
serious mishap. It is still in weekly use, but not quite the daily use
that it once was. For some types of repair, the swinging needle of a
quality instrument like this, is so much more appropriate than a
digital type ...


Its a well known fact that the human eye can gain a rough ideas of
what's going on much faster with an analogue display, as it takes longer
to read a digital display, although in the end that is more accurate.

I have never felt the need for a DVM or DAM..99.99% of voltage and
current readings are of the 'is it within 20% of where it should be'
flavour.

The fact is an LCD meter is CHEAPER than a quality moving needle
display.

Not better.

But probably more shockproof.

--
Use the BIG mirror service in the UK:
http://www.mirrorservice.org

*lightning protection* - a w_tom conductor

In message , Arfa Daily
writes


"Robin" wrote in message
...
Arfa Daily wrote:
Anybody got a copy of the schematic that's in the back of the user
guide that they can scan for me, please ? I've searched all my files
and drawers high and low, and can't find my book anywhere ... I
thought that the 'net would be awash with copies of the schematic,
but it seems only for the Mk 2, which is totally different to the MK
4.
TIA

Is it the circuit diagram at
http://www.radiomuseum.org/r/avo_uni...er_8_mk_i.html ?
(Registration necessary for download. I have not done it as mine's a
Mk II.)
-- Robin
PM may be sent to rbw0{at}hotmail{dot}com


Hi Robin, thanks for that. It would appear to be the correct one. Looks
as though you need to pay to become a member, so I will hold off for
now until all the feelers that I have out, run dry. It's really
annoying because I have owned the meter from new when I was an
apprentice, and I have the book, which has the schematic in it,
carefully filed away somewhere, but I'm buggered if I can now find it.
It is in a box file, but said boxfile is not where I know it should be.
Even more annoying is that I have damaged the meter by my own
stupidity, so now have the need to fix it ... :-(


http://www.vintage-radio.net/forum/showthread.php?t=756
----
http://www.g1jbg.co.uk/service.htm
Any good?
--
Ian

In article ,
The Natural Philosopher wrote:
You'd have to have a lot of ranges on a 'needle' display to give
anywhere near the accuracy of a 3 quid DVM.

Who wants the accuracy?

Well, the Model 8 ceased to be an industry standard after high input
impedance meters became available at a reasonable price.

--
*To steal ideas from *one* person is plagiarism; from many, research*

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Plowman (News) wrote:
In article ,
The Natural Philosopher wrote:
You'd have to have a lot of ranges on a 'needle' display to give
anywhere near the accuracy of a 3 quid DVM.

Who wants the accuracy?

Well, the Model 8 ceased to be an industry standard after high input
impedance meters became available at a reasonable price.

And that is probably why the BIG avos are not being made.. too expensive
and cant do the accuracy,.


a 5% moving coil meter is what I use..

The Natural Philosopher wrote:
Dave Plowman (News) wrote:
In article ,
The Natural Philosopher wrote:
You'd have to have a lot of ranges on a 'needle' display to give
anywhere near the accuracy of a 3 quid DVM.

Who wants the accuracy?

Well, the Model 8 ceased to be an industry standard after high input
impedance meters became available at a reasonable price.

And that is probably why the BIG avos are not being made.. too expensive
and cant do the accuracy,.


a 5% moving coil meter is what I use..

The main thing to be aware of when using a DMM on old equipment is that
the loading imposed by the meter is different, so, especially on valve
circuits, the reference voltages will change. Voltages on some old gear
that I use here is specified as being measured on an AVO Model 8, and
takes account of the load presented by a 20 Kilohm/volt meter mechanism.
Other meters, even other 20Kohm/ V types did not always give the right
results, if the ranges didn't match the AVO's.

On the other hand, analogue meter movements with better than 5% accuracy
aren't cheap, and most DMMs now will easily and repeatably do 1% +- 1
count on the last digit.

Newer gear has voltages specified as measured by a fixed 10 Megohm meter
impedance, so an AVO 8 or any other anlogue meter may well give wrong
results on it.

--
Tciao for Now!

John.

In article ,
John Williamson wrote:
The main thing to be aware of when using a DMM on old equipment is that
the loading imposed by the meter is different, so, especially on valve
circuits, the reference voltages will change. Voltages on some old gear
that I use here is specified as being measured on an AVO Model 8, and
takes account of the load presented by a 20 Kilohm/volt meter mechanism.
Other meters, even other 20Kohm/ V types did not always give the right
results, if the ranges didn't match the AVO's.

Yes. But some instances where that loading also gave a meaningless reading
- so you had to go to a very expensive and delicate valve volt meter.

On the other hand, analogue meter movements with better than 5% accuracy
aren't cheap, and most DMMs now will easily and repeatably do 1% +- 1
count on the last digit.

Indeed - and can survive being dropped. And fit in the pocket.

Newer gear has voltages specified as measured by a fixed 10 Megohm meter
impedance, so an AVO 8 or any other anlogue meter may well give wrong
results on it.

Other thing is - quite pertinent to this group - is a high impedance meter
will often give a reading on bunched etc mains wiring where there is
nothing connected to it. An old AVO, since it draws much more current,
probably not.

--
*Sticks and stones may break my bones but whips and chains excite me*

Dave Plowman London SW
To e-mail, change noise into sound.

"Arfa Daily" wrote in message
...


"Ian Field" wrote in message
...

"Arfa Daily" wrote in message
...


"Robin" wrote in message
...
Arfa Daily wrote:
Anybody got a copy of the schematic that's in the back of the user
guide that they can scan for me, please ? I've searched all my files
and drawers high and low, and can't find my book anywhere ... I
thought that the 'net would be awash with copies of the schematic,
but it seems only for the Mk 2, which is totally different to the MK
4.
TIA

Is it the circuit diagram at
http://www.radiomuseum.org/r/avo_uni...er_8_mk_i.html ?
(Registration necessary for download. I have not done it as mine's a
Mk II.)
--
Robin
PM may be sent to rbw0{at}hotmail{dot}com


Hi Robin, thanks for that. It would appear to be the correct one. Looks
as though you need to pay to become a member, so I will hold off for now
until all the feelers that I have out, run dry. It's really annoying
because I have owned the meter from new when I was an apprentice, and I
have the book, which has the schematic in it, carefully filed away
somewhere, but I'm buggered if I can now find it. It is in a box file,
but said boxfile is not where I know it should be. Even more annoying is
that I have damaged the meter by my own stupidity, so now have the need
to fix it ... :-(

There may be an outside chance its turned up on
alt.binaries.e-book.technical at some time or other.

Whether I'd have downloaded it is another matter, and it would take a
while to search my archives.

You could try a REQ: on that group while I try to remember where I put
all the unsorted stuff.


Thanks Ian. Be appreciated if you were able to have a quick look. Wouldn't
have been a problem back in our old TeleMag days. John would have flung an
ad in "Help Wanted" for me ... :-)


All I found is the AVO 8 MKII user manual with schematic and a document
claiming to be the AVO 8 service manual, its a collection of pages in
typewriter font describing servicing proceedures - no illustrations.

If you want them name a binaries I can upload to.

Have you tried BAMA? - I haven't been there since they changed their website
to stop people like me leeching the whole lot - they've undoubtedly added
new stuff since then.

"The Natural Philosopher" wrote in message
...
Arfa Daily wrote:


"Meat Plow" wrote in message
news
On Fri, 01 Apr 2011 21:46:53 +0100, Arfa Daily wrote:

"Robin" wrote in message
...
Arfa Daily wrote:
Anybody got a copy of the schematic that's in the back of the user
guide that they can scan for me, please ? I've searched all my files
and drawers high and low, and can't find my book anywhere ... I
thought that the 'net would be awash with copies of the schematic,
but
it seems only for the Mk 2, which is totally different to the MK 4.
TIA

Is it the circuit diagram at
http://www.radiomuseum.org/r/avo_uni...er_8_mk_i.html ?
(Registration necessary for download. I have not done it as mine's a
Mk II.)
--
Robin
PM may be sent to rbw0{at}hotmail{dot}com


Hi Robin, thanks for that. It would appear to be the correct one. Looks
as though you need to pay to become a member, so I will hold off for
now
until all the feelers that I have out, run dry. It's really annoying
because I have owned the meter from new when I was an apprentice, and I
have the book, which has the schematic in it, carefully filed away
somewhere, but I'm buggered if I can now find it. It is in a box file,
but said boxfile is not where I know it should be. Even more annoying
is
that I have damaged the meter by my own stupidity, so now have the need
to fix it ... :-(

Arfa

That's too bad. I have some old gear I used as an apprentice that have a
high value in the nostalgia department. An old EICO 232 VTVM, B&K 1801
freq. counter, Beckman Tech 310 DVM, Amprobe Amp Clamp and some other
things that I can't think of right now.




Yes, Meat. It's very frustrating. I cut my 'professional' teeth with that
meter, and it has served me faithfully over the years without serious
mishap. It is still in weekly use, but not quite the daily use that it
once was. For some types of repair, the swinging needle of a quality
instrument like this, is so much more appropriate than a digital type ...


Its a well known fact that the human eye can gain a rough ideas of what's
going on much faster with an analogue display, as it takes longer to read
a digital display, although in the end that is more accurate.

I have never felt the need for a DVM or DAM..99.99% of voltage and current
readings are of the 'is it within 20% of where it should be' flavour.

Mine are a couple of Taylor meters, the big one is 100k/V but neither has AC
current ranges.

The small one has an early proto-HF ESR bridge glued to the front panel,
which was abandoned because it blots out FM reception for about the radius
of the block of flats.

On the big one I dropped a pair of pliers on it and broke the glass - it now
has a strip of motorcycle helmet visor stuck on with superglue.

When the 30V high-ohms battery became unavailable I built a 30V (zener
shunted) blocking oscillator into the battery compartment, connected via a
pushbutton to the 1.5V low ohms battery.

There's a sort of cube of dust layer in the gap at the end of the
bookshelf - I think that might be it!

There's a couple of genuine old windy-handle Meggers laying about somewhere
too.

Dave Plowman (News) wrote:
In article ,
John Williamson wrote:
The main thing to be aware of when using a DMM on old equipment is that
the loading imposed by the meter is different, so, especially on valve
circuits, the reference voltages will change. Voltages on some old gear
that I use here is specified as being measured on an AVO Model 8, and
takes account of the load presented by a 20 Kilohm/volt meter mechanism.
Other meters, even other 20Kohm/ V types did not always give the right
results, if the ranges didn't match the AVO's.

Yes. But some instances where that loading also gave a meaningless reading
- so you had to go to a very expensive and delicate valve volt meter.

Which was normally specified on the schematic.

On the other hand, analogue meter movements with better than 5% accuracy
aren't cheap, and most DMMs now will easily and repeatably do 1% +- 1
count on the last digit.

Indeed - and can survive being dropped. And fit in the pocket.

In the case of one of mine, without showing a bulge. It's 5mm thick, and
autoranges.

Newer gear has voltages specified as measured by a fixed 10 Megohm meter
impedance, so an AVO 8 or any other anlogue meter may well give wrong
results on it.

Other thing is - quite pertinent to this group - is a high impedance meter
will often give a reading on bunched etc mains wiring where there is
nothing connected to it. An old AVO, since it draws much more current,
probably not.

So, basically, you're saying use the appropriate meter for the job.

--
Tciao for Now!

John.

Ian Field explained :
When the 30V high-ohms battery became unavailable I built a 30V (zener
shunted) blocking oscillator into the battery compartment, connected via a
pushbutton to the 1.5V low ohms battery.

They are still available, but many simply make up a holder to stack
button cells to the value of 30v.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

"Ian Field" wrote in message
...

"Arfa Daily" wrote in message
...


"Ian Field" wrote in message
...

"Arfa Daily" wrote in message
...


"Robin" wrote in message
...
Arfa Daily wrote:
Anybody got a copy of the schematic that's in the back of the user
guide that they can scan for me, please ? I've searched all my files
and drawers high and low, and can't find my book anywhere ... I
thought that the 'net would be awash with copies of the schematic,
but it seems only for the Mk 2, which is totally different to the MK
4.
TIA

Is it the circuit diagram at
http://www.radiomuseum.org/r/avo_uni...er_8_mk_i.html ?
(Registration necessary for download. I have not done it as mine's a
Mk II.)
--
Robin
PM may be sent to rbw0{at}hotmail{dot}com


Hi Robin, thanks for that. It would appear to be the correct one. Looks
as though you need to pay to become a member, so I will hold off for
now until all the feelers that I have out, run dry. It's really
annoying because I have owned the meter from new when I was an
apprentice, and I have the book, which has the schematic in it,
carefully filed away somewhere, but I'm buggered if I can now find it.
It is in a box file, but said boxfile is not where I know it should be.
Even more annoying is that I have damaged the meter by my own
stupidity, so now have the need to fix it ... :-(

There may be an outside chance its turned up on
alt.binaries.e-book.technical at some time or other.

Whether I'd have downloaded it is another matter, and it would take a
while to search my archives.

You could try a REQ: on that group while I try to remember where I put
all the unsorted stuff.


Thanks Ian. Be appreciated if you were able to have a quick look.
Wouldn't have been a problem back in our old TeleMag days. John would
have flung an ad in "Help Wanted" for me ... :-)


All I found is the AVO 8 MKII user manual with schematic and a document
claiming to be the AVO 8 service manual, its a collection of pages in
typewriter font describing servicing proceedures - no illustrations.

If you want them name a binaries I can upload to.

Have you tried BAMA? - I haven't been there since they changed their
website to stop people like me leeching the whole lot - they've
undoubtedly added new stuff since then.

A friend of mine has access to Model 8 I, II, III, V, VI, and VII , but no
IV. Curious ... Interestingly, I have now found my book, which I was
absolutely certain was issued to me with the meter, and it's for a
Mk III , which is entirely different. Hmmm ...

I just went and looked at a BAMA mirror site, and lo ! I have found a file
that says it's for the Mk IV. I've downloaded it, but now need to find some
software to open it. It says that it is .DJVU format ??

Arfa

"Dave Plowman (News)" wrote in message
...
In article ,
The Natural Philosopher wrote:
The fact is an LCD meter is CHEAPER than a quality moving needle display.

Not better.

You'd have to have a lot of ranges on a 'needle' display to give anywhere
near the accuracy of a 3 quid DVM. They're also far more difficult to read
accurately. But for seeing the direction and rate of change of some things
can be useful.

My AVO 8 - also bought when I started work - stays on the shelf.

--
*Sometimes I wake up grumpy; Other times I let him sleep.

Dave Plowman London SW
To e-mail, change noise into sound.

Send it to a good home then, Dave. Want my address ? :-)

Arfa

"Ian Jackson" wrote in message
...
In message , Arfa Daily
writes


"Robin" wrote in message
...
Arfa Daily wrote:
Anybody got a copy of the schematic that's in the back of the user
guide that they can scan for me, please ? I've searched all my files
and drawers high and low, and can't find my book anywhere ... I
thought that the 'net would be awash with copies of the schematic,
but it seems only for the Mk 2, which is totally different to the MK
4.
TIA

Is it the circuit diagram at
http://www.radiomuseum.org/r/avo_uni...er_8_mk_i.html ?
(Registration necessary for download. I have not done it as mine's a Mk
II.)
-- Robin
PM may be sent to rbw0{at}hotmail{dot}com


Hi Robin, thanks for that. It would appear to be the correct one. Looks as
though you need to pay to become a member, so I will hold off for now
until all the feelers that I have out, run dry. It's really annoying
because I have owned the meter from new when I was an apprentice, and I
have the book, which has the schematic in it, carefully filed away
somewhere, but I'm buggered if I can now find it. It is in a box file, but
said boxfile is not where I know it should be. Even more annoying is that
I have damaged the meter by my own stupidity, so now have the need to fix
it ... :-(


http://www.vintage-radio.net/forum/showthread.php?t=756
----
http://www.g1jbg.co.uk/service.htm
Any good?
--
Ian

Yep. Been to all those places Ian. Thanks anyway

Arfa

Dave Plowman (News) wrote in message
...
In article ,
Harry Bloomfield wrote:
Have you tried AVO direct? They still make the Model 8, IIRC.

They stopped making it about, oh - two or three years ago. I think too
expensive, too complex to make were the reasons quoted.

They were certainly very expensive last time I saw them for sale - about
700 quid? So most probably just bought for a museum or display purposes.

--
*Could it be that "I do " is the longest sentence? *

Dave Plowman London SW
To e-mail, change noise into sound.



Perhaps like Fluke 75 actually specified by name and model in a particular
statutary regulation . So if you use anything other than a Fluke 75 it may
be an illegal act

I just went and looked at a BAMA mirror site, and lo ! I have found a
file that says it's for the Mk IV. I've downloaded it, but now need
to find some software to open it. It says that it is .DJVU format ??

The site has links to viewers: see eg
http://bama.edebris.com/manuals/avo FWIW I use Irfan. And you will
need then the djvu plug-in (from the same site). But I am sorry to have
to tell you that if you have downloaded mk4elect.djvu it is the manual
for the Avo Electronic Testmeter Mark 4. (I know 'cos I got some of my
manuals from BAMA and looked there yesterday when you first asked: I am
*really* looking for excuses not to get back to crawling around in the
loft!)

--
Robin
PM may be sent to rbw0{at}hotmail{dot}com

N_Cook wrote:
So if you use anything other than a Fluke 75 it may
be an illegal act

....As the actress said the the bishop, stirring her tea...

In message , Arfa Daily
writes


"Ian Jackson" wrote in message
...



http://www.vintage-radio.net/forum/showthread.php?t=756
----
http://www.g1jbg.co.uk/service.htm
Any good?
-- Ian

Yep. Been to all those places Ian. Thanks anyway

Ah! The Mk 4 is an AVO Multiminor - not an Avo 8. Sorry!
--
Ian

"Arfa Daily" wrote in message
...


"Ian Field" wrote in message
...

"Arfa Daily" wrote in message
...


"Ian Field" wrote in message
...

"Arfa Daily" wrote in message
...


"Robin" wrote in message
...
Arfa Daily wrote:
Anybody got a copy of the schematic that's in the back of the user
guide that they can scan for me, please ? I've searched all my files
and drawers high and low, and can't find my book anywhere ... I
thought that the 'net would be awash with copies of the schematic,
but it seems only for the Mk 2, which is totally different to the MK
4.
TIA

Is it the circuit diagram at
http://www.radiomuseum.org/r/avo_uni...er_8_mk_i.html ?
(Registration necessary for download. I have not done it as mine's a
Mk II.)
--
Robin
PM may be sent to rbw0{at}hotmail{dot}com


Hi Robin, thanks for that. It would appear to be the correct one.
Looks as though you need to pay to become a member, so I will hold off
for now until all the feelers that I have out, run dry. It's really
annoying because I have owned the meter from new when I was an
apprentice, and I have the book, which has the schematic in it,
carefully filed away somewhere, but I'm buggered if I can now find it.
It is in a box file, but said boxfile is not where I know it should
be. Even more annoying is that I have damaged the meter by my own
stupidity, so now have the need to fix it ... :-(

There may be an outside chance its turned up on
alt.binaries.e-book.technical at some time or other.

Whether I'd have downloaded it is another matter, and it would take a
while to search my archives.

You could try a REQ: on that group while I try to remember where I put
all the unsorted stuff.


Thanks Ian. Be appreciated if you were able to have a quick look.
Wouldn't have been a problem back in our old TeleMag days. John would
have flung an ad in "Help Wanted" for me ... :-)


All I found is the AVO 8 MKII user manual with schematic and a document
claiming to be the AVO 8 service manual, its a collection of pages in
typewriter font describing servicing proceedures - no illustrations.

If you want them name a binaries I can upload to.

Have you tried BAMA? - I haven't been there since they changed their
website to stop people like me leeching the whole lot - they've
undoubtedly added new stuff since then.

A friend of mine has access to Model 8 I, II, III, V, VI, and VII , but no
IV. Curious ... Interestingly, I have now found my book, which I was
absolutely certain was issued to me with the meter, and it's for a
Mk III , which is entirely different. Hmmm ...

I just went and looked at a BAMA mirror site, and lo ! I have found a file
that says it's for the Mk IV. I've downloaded it, but now need to find
some software to open it. It says that it is .DJVU format ??


Lizardtech DJVU is a PITA but it produces small files - the main problems
are lack of scrolling and you can't set it to restore last viewed page next
time you open it.

What I do is open the DJVU with the IE pluggin and hit print with Cutepdf
installed (creates a virtual printer which is actually a PDF file), you have
to jump to the last page in the DJVU and when the settings box opens reset
the from box to 1.

On Sat, 02 Apr 2011 10:45:22 +0100, Arfa Daily wrote:

"Meat Plow" wrote in message
news
On Fri, 01 Apr 2011 21:46:53 +0100, Arfa Daily wrote:

"Robin" wrote in message
...
Arfa Daily wrote:
Anybody got a copy of the schematic that's in the back of the user
guide that they can scan for me, please ? I've searched all my files
and drawers high and low, and can't find my book anywhere ... I
thought that the 'net would be awash with copies of the schematic,
but it seems only for the Mk 2, which is totally different to the MK
4. TIA

Is it the circuit diagram at
http://www.radiomuseum.org/r/avo_uni...er_8_mk_i.html ?
(Registration necessary for download. I have not done it as mine's a
Mk II.)
--
Robin
PM may be sent to rbw0{at}hotmail{dot}com


Hi Robin, thanks for that. It would appear to be the correct one.
Looks as though you need to pay to become a member, so I will hold off
for now until all the feelers that I have out, run dry. It's really
annoying because I have owned the meter from new when I was an
apprentice, and I have the book, which has the schematic in it,
carefully filed away somewhere, but I'm buggered if I can now find it.
It is in a box file, but said boxfile is not where I know it should
be. Even more annoying is that I have damaged the meter by my own
stupidity, so now have the need to fix it ... :-(

Arfa

That's too bad. I have some old gear I used as an apprentice that have
a high value in the nostalgia department. An old EICO 232 VTVM, B&K
1801 freq. counter, Beckman Tech 310 DVM, Amprobe Amp Clamp and some
other things that I can't think of right now.




Yes, Meat. It's very frustrating. I cut my 'professional' teeth with
that meter, and it has served me faithfully over the years without
serious mishap. It is still in weekly use, but not quite the daily use
that it once was. For some types of repair, the swinging needle of a
quality instrument like this, is so much more appropriate than a digital
type ...

Arfa
--

I got used to the LCD after using one for 25 years but it took awhile
after using the EICO and a Simpson. The Beckman 310 was the first LCD I
owned. I found a benchtop Beckman with LED's back in the 90's I used for
several years before it failed beyond repair. Now using my faithful Fluke
77. This is one that had a touch hold button in the middle of the
selector. It's hard to put aside the tools you've learned to trust after
decades.



--
Live Fast Die Young, Leave A Pretty Corpse