AVO 8 Mk 4 ...
Arfa Daily
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
Robin
http://www.radiomuseum.org/r/avo_universal_avometer_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
Arfa Daily
"Robin" <s...@sig.sep> wrote in message
news:97olp.1305$bT6...@newsfe05.ams2...
Hi Robin, thanks for that. It would appear to be the correct one. Looks as
though you need to pay to become a member, so I will hold off for now until
all the feelers that I have out, run dry. It's really annoying because I
have owned the meter from new when I was an apprentice, and I have the book,
which has the schematic in it, carefully filed away somewhere, but I'm
buggered if I can now find it. It is in a box file, but said boxfile is not
where I know it should be. Even more annoying is that I have damaged the
meter by my own stupidity, so now have the need to fix it ... :-(
Arfa
Ian Field
"Arfa Daily" <arfa....@ntlworld.com> wrote in message
news:5Rqlp.4508$o81....@newsfe28.ams2...
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.
Meat Plow
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
John Williamson
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.
Terry Casey
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
Mike Tomlinson
<arfa....@ntlworld.com> writes
> Even more annoying is that I have damaged the
>meter by my own stupidity
Measured the resistance of the mains?
BTDTGTTS.
--
(\__/)
(='.'=)
(")_(")
Trevor Wilson
**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
Dave Plowman (News)
Have you tried AVO direct? They still make the Model 8, IIRC.
--
*Dance like nobody's watching.
Dave Plowman da...@davenoise.co.uk London SW
To e-mail, change noise into sound.
Andy Dingley
> **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.
Arfa Daily
"Dave Plowman (News)" <da...@davenoise.co.uk> wrote in message
news:51bd54e...@davenoise.co.uk...
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
Harry Bloomfield
> In article <Cqmlp.4035$KZ7...@newsfe08.ams2>,
> Arfa Daily <arfa....@ntlworld.com> wrote:
>> Anybody got a copy of the schematic that's in the back of the user guide
>> that they can scan for me, please ? I've searched all my files and
>> drawers high and low, and can't find my book anywhere ... I thought
>> that the 'net would be awash with copies of the schematic, but it seems
>> only for the Mk 2, which is totally different to the MK 4.
>
> Have you tried AVO direct? They still make the Model 8, IIRC.
They stopped making it about, oh - two or three years ago. I think too
expensive, too complex to make were the reasons quoted.
--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk
John Williamson
simultaneous nostalgia and relief that reference quality meters now
weighed less than a sack of coal. ;-)
Arfa Daily
"Ian Field" <gangprob...@ntlworld.com> wrote in message
news:c1rlp.2624$Pi....@newsfe22.ams2...
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
Arfa Daily
"Meat Plow" <mhyw...@yahoo.com> wrote in message
news:pan.2011.04...@lmao.lol.lol...
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
> --
The Natural Philosopher
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
>> --
>
>
Dave Plowman (News)
Harry Bloomfield <harry...@NOSPAM.tiscali.co.uk> 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? *
Geo
Not MK4 but MK3 is here:-
http://www.richardsradios.co.uk/avo8.html
MK4 on ebay but high priced (IMO):-
http://cgi.ebay.co.uk/Avo8-Mk4-Manual-Circuit-/270727895670#ht_500wt_1156
Ian Jackson
<arfa....@ntlworld.com> writes
>
>
http://www.vintage-radio.net/forum/showthread.php?t=756
---->
http://www.g1jbg.co.uk/service.htm
Any good?
--
Ian
Ian Field
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.
Arfa Daily
"Ian Field" <gangprob...@ntlworld.com> wrote in message
news:I2Flp.7637$5t2....@newsfe06.ams2...
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
Arfa Daily
"Ian Jackson" <ianREMOVET...@g3ohx.demon.co.uk> wrote in message
news:CZnwdpQd...@g3ohx.demon.co.uk...
Yep. Been to all those places Ian. Thanks anyway
Arfa
Arfa Daily
"Geo" <hw9j...@dea.spamcon.org> wrote in message
news:mfudp6pnu6aleqg8i...@4ax.com...
Thanks Geo. The Mk 3 is quite different from the 4. I guess that the high
price on eBay is commanded by the fact that it seems to be a lot rarer than
I thought it was ...
Arfa
N_Cook
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
Arfa Daily
Result ! It's fixed ! Looking at all the schematics for the other marks,
they all seemed to use a fairly straightforward AC voltage measuring scheme,
employing two diodes in bridge with two resistors, for the rectification. In
view of the fact that I'd twatted it with a high pulse voltage, I figured
that the most likely bet was those diodes. When I found them, they were
white glass ones type HG5808, so a fairly bog-standard germanium type.
Casting around in the parts drawers, I found a packet of brand new OA91s, so
I bunged a couple in, and voila ! - my good old AVO is now reading the right
thing again on AC volts
Arfa
Robin
> 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 ??
>
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!)
The Natural Philosopher
> So if you use anything other than a Fluke 75 it may
> be an illegal act
>
>
>
Ian Jackson
<arfa....@ntlworld.com> writes
>
>
>"Ian Jackson" <ianREMOVET...@g3ohx.demon.co.uk> wrote in message
news:CZnwdpQd...@g3ohx.demon.co.uk...
>>
>>
>> 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
Ian Field
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.
Meat Plow
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
Arfa Daily
"Robin" <s...@sig.sep> wrote in message
news:iaHlp.2408$Ir....@newsfe13.ams2...
I got me a viewer (I actually have Irfan as well, but didn't realise it did
these djvu's) and yes, you are quite right, it is the wrong one, even though
it appears to be listed as one of the 8's. Anyways, meter is now fixed - see
my later post ! :-)
Arfa
Arfa Daily
Indeed it is. I have a hand portable DMM that is now the main workshop
workhorse, and I am very easy with it. I also have a bench true RMS 6 digit
job that is used fairly rarely. The AVO still gets used where I feel it is
the appropriate instrument for the job. I tend to be happier using it around
tube circuitry for measuring volts, and I prefer its ohms ranges for
measuring semiconductor junctions, even though the DMM has a diode test
facility
Arfa
H. Neary
It's what you are used to. I started out with an AVO 7 I think it
was 500 Ohms per Volt. It certainly had an effect on circuits even in
the days before CMOS.
I could turn on transistors and generally interact with circuits using
it. Although a tool no doubt aimed at Electrical Engineers it proved a
useful diagnostic instrument in an electronics environment.
Oddly enough the AVO eight was potentially more accurate than todays
digital afferings. At 20 K to the Volt, The AVO took half the current
of the modern DMM.
It was a dashed big needle to shift too.
My gripe with the AVO was that although it was a robust instrument,
you could buy around fifteen less robust meters for the same price.
Similar accuracy, smaller scale though and at a major price reduction.
Plus of course the fact that you could buy batteries to keep the Ohm
fires burning at your local newsagent. I seem to recollect tht The AVO
needed some kind of battery / inverter replacement when Ever Ready
stopped producing their very expensive box of volts.
Incidentally the final AVOs were not robust. They weighed about as
much as two of the £12-00 Tandy meters that I used to use at that
time.
That was prety light! I zapped a new AVO with one jab at a line output
valve topcap. Around 800 V p-p at 15 khz.
I still operate using the same philosophy today. I can pay a hundred
or so for a Fluke, or throw £20-00 across the counter at Maplin. Both
meters do the same at an acceptable accuracy and both share the same
fate when I forget to go from mA to volts when measuring across
phases. Both meters also tend to go green & gungy when exposed to
liquids. At least I do not feel too bad with a defunct £20-00 Tandy
HN
Windmill
>In article <5Rqlp.4508$o81....@newsfe28.ams2>, Arfa Daily
><arfa....@ntlworld.com> writes
>> Even more annoying is that I have damaged the
>>meter by my own stupidity
>Measured the resistance of the mains?
You too, eh?
But they are indeed tough beasts; apart from a shaky ohms-adjust pot
it's still working 25 years later.
Doubtful if you could do that with a modern DVM and get away with it.
--
Windmill, Use t m i l l
Til...@Nonetel.com @ O n e t e l
. c o m
Mike Tomlinson
sp...@Onetel.net.uk.invalid> writes
>Doubtful if you could do that with a modern DVM and get away with it.
The one I measured the mains with was a mid-range ISO-Tech something or
other. It blew the internal fuse and worked OK after replacement. But
doubt many of the five quid cheapies would survive.
--
(\__/)
(='.'=)
(")_(")
Ian Jackson
<arfa....@ntlworld.com> writes
>
>
interesting things):
http://www.tuberadio.it/
http://www.tuberadio.it/utils.htm
http://www.tuberadio.it/download/dvs31.exe
--
Ian
Ian Field
>
>
> "Robin" <s...@sig.sep> wrote in message
> news:iaHlp.2408$Ir....@newsfe13.ams2...
>>> 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
>>
>
> I got me a viewer (I actually have Irfan as well, but didn't realise it
> did these djvu's)
Can't remember the exact reason why I stopped using Irfanview for DJVU and
went back to the original publishers browser pluggin but the most recent
download of DJVU certainly works much better than earlier versions.
Ian Field
"H. Neary" <ŁŁŁnearyhŁŁŁ@clara.co.uk> wrote in message
news:10jfp69d6r5mh7p46...@4ax.com...
Had that problem with my Taylor meter - I wound a blocking oscillator coil
on a small toroid and simply shunted the output with a 30V zener, its
connected via a pushbutton to the 1.5V low Ohms battery.
Ian Field
"Windmill" <spam-n...@Onetel.net.uk.invalid> wrote in message
news:LJ29u...@freebie.onetel.net.uk...
> Mike Tomlinson <mi...@jasper.org.uk> writes:
>
>>In article <5Rqlp.4508$o81....@newsfe28.ams2>, Arfa Daily
>><arfa....@ntlworld.com> writes
>>> Even more annoying is that I have damaged the
>>>meter by my own stupidity
>>Measured the resistance of the mains?
>
> You too, eh?
> But they are indeed tough beasts; apart from a shaky ohms-adjust pot
> it's still working 25 years later.
>
> Doubtful if you could do that with a modern DVM and get away with it.
My first ever DMM was fished out of the bin where I worked at the time, Ohms
& ACV didn't work.
When I opened it there was an OP-AMP in the middle of the PCB - it was sort
of easiest to try replacing that and it actually fixed the fault!
The employer very kindly loaned me a recently calibrated instrument and an
assortment of adjustable PSUs and resistance decade boxes so I could make
the neccessary adjustments to the presets next to the OP-AMP.
I still have it but its been relegated to the shed for occasional automotive
work.
JW
(Windmill) wrote in Message id: <LJ29u...@freebie.onetel.net.uk>:
>Mike Tomlinson <mi...@jasper.org.uk> writes:
>
>>In article <5Rqlp.4508$o81....@newsfe28.ams2>, Arfa Daily
>><arfa....@ntlworld.com> writes
>>> Even more annoying is that I have damaged the
>>>meter by my own stupidity
>>Measured the resistance of the mains?
>
>You too, eh?
>But they are indeed tough beasts; apart from a shaky ohms-adjust pot
>it's still working 25 years later.
>
>Doubtful if you could do that with a modern DVM and get away with it.
Not a cheap one maybe. My bench meter is a Keithley 2000 that will take
1KV peak when in resistance mode. Not that I'd do it on purpose, though...
:)
Mark Zacharias
news:mr5jp61anu3bt8n1d...@4ax.com...
A Fluke 80 series III or later can survive this - not sure about the
original 80 series.
I wouldn't do it intentionally just to prove a point, though...
Mark Z.