# The Avo



## BobClay (Dec 14, 2007)

When I was at sea I carried a Fluke digital meter of my own which I bought in the 70's. Great meter, been dropped in bilges and onto decks from heights and it's still going strong. Absolute necessity when working on solid states.

However, I was recently fiddling with some solar panels in order to charge a battery and found that when it comes to measuring current, for some reason I can't explain, an analogue meter just gives more satisfaction physically. A needle swinging up and over.

So I found myself on ebay looking for an AVO (I presume the firm has long since gone to the wall... but I don't know that for sure.) Got myself a Mark 8 still in the leather case for £20 and when using it out in the garage have found it very accurate and reliable. Yep, it is big, and clumsy, and certainly delicate ... but it is very satisfying.

AM I GETTING OLD OR WHAT .... ???(Pint)


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## Satanic Mechanic (Feb 23, 2009)

nope not at all - things like diodes can throw digital instruments all over the place - not so analogue. 

Another reason I tend towards analogue is because the vast majority of the time I more interested in a go/no go indication rather than a measured quantity and a moving needle does that better for me than a self ranging digital.

good price by the way

Oh and Avo got taken over by Megger


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## trotterdotpom (Apr 29, 2005)

Wow ... Do they still have diodes? How "retro"!

AVOs are are also handy for doing Personality Tests on prospective Scientologists. Come to think of it, a Megger would be pretty good for that too.

John T


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## iain48 (Oct 19, 2005)

I never seen a Fluke until much later than the seventies. I have one now (seldom used except for checking domestic plug top fuses).At the end of the day apart from the bulk of the Avo I preferred the swing of the needle.


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## Varley (Oct 1, 2006)

The essential is that it is low impedance and all DVMs are 'naturally' high impedance. Many, many wild geese have easily fled before the whizz kid with the DVM realises that the voltage he thought he had , he hasn't. There is now a Fluke with a special low impedance setting otherwise stick to an 'analogue'. (The flick seen from the corner of the eye cannot be emulated either - as for back to front ratios - fractionally more skill/knowledge required but it is always the same with an analogue - some DVMs tell you more but who really wants to be presented with a reading of the forward voltage drop - appreciation that there is one might be important (the so called loss free droppers) - but has anyone ever found a failed diode with a low forward drop that doesn't also have low/low resitance ratio?

One of the items it is never worth omitting from 'radio fault finding' is to specify with what sort of meter you want a measurement taken. I did not do this until my failing earned me a trip to the PG to find a disconnected tacho signal preventing Shaft Generator operation. There with Mantronic box disconnected to access terminals. Measured DVM within tolerance when measured with AVO zero. A lesson well learned as it was when the wogs were one of their turmoils and the first mine of the season got a launch rendezvousing off Khor Fakkan the day after mine!

On one occasion when only DVM available the astonished (and certificated E/O) found the problem with the battery and lamp I had forced him to try.

John - unless the 'high tech' integrated, surface mount, DIL packaged, software dependent and largely unnecessary crap can translate turning into a live main bus then I suggest the diodes on a brushless alternator rank as the most essential semiconductors onboard. But great idea for correcting superstition.


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## BobClay (Dec 14, 2007)

Fluke 77, tough as old boots. Mmm, you might be right about the 70's, but I carried when at sea for several years, and left the sea in 1986, was sure I bought it in late 70s. 
The AVO, bought on ebay. Good meter, but couldn't really get on with it onboard ship with solid state electronics. Like it a lot in my garage though.
Sorry about the mistake in the picture (i.e. the Sun shining, it's been raining for 24 hours but soon as I picked up the camera it poked it's face from behind the clouds.)


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## mikeg (Aug 24, 2006)

I've great respect for the venerable Avo 8, it was mostly all I wanted for faultfinding in the RR and on the bridge. Like others I carried a quality Digital meter as the bulk of the Avo 8 was impracticable in some areas. There is something reassuring about the analogue meter, especially when adjusting/tuning for peak or watching trends. Later some digital meters had an additional analogue type display built in to do much the same. Happy days.


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## andysk (Jun 16, 2005)

BobClay said:


> ..... I presume the firm has long since gone to the wall... but I don't know that for sure. ...


They are still around Bob, or at least the building is, under the Megger banner, very visible from the A20 on the first roundabout as you come down the hill from the west into Dover.


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## trotterdotpom (Apr 29, 2005)

Clear glass light bulbs were much better than those frosted glass ones. If they went out, you could see if the filament was broken and didn't have to do a continuity test. Phew.

John T


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## BobClay (Dec 14, 2007)

Glass bulbs ? .... do they still have those .... ?


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## gwzm (Nov 7, 2005)

You can't beat a decent analogue meter for fault finding around cars, audio amplifiers, ham radio kit etc. etc. DVMs are useful but it's the trusty old AVO that gets used most of the time.

gwzm


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## Shipbuilder (Jun 30, 2005)

I was never a fan of the clumsy AVO 8 and preferred smaller meters. But I have always found that I can "interpret" an analogue meter reading better. When the needle goes blurred, I know there is some sort of ripple getting in etc etc. Recently, I got a dandy little Avo Minor on a car boot sale for £4 and it works a treat and can deal with measurements that my digital gets confused with!
Can't use it for ohms as I can't get a battery, but the digital reigns supreme in that field. Its ranges are Volts - 5 - 25 - 100 - 250 and 500 (AC & DC) mA 2.5 - 5 - 25 - 100 - 500 (DC only) Ohms - a pathetic 2,000 - but I like it.
Bob


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## Mad Landsman (Dec 1, 2005)

This thread got me thinking - I was given an AVO 8 years ago and when I got it home I discovered why - The idiot had let the batteries rot and it was useless. 
So I have just had look on the internet and Megger still list the AVO Model 8 Mk7 but with the words: 'After a long and distinguished career the AVOMETER® Model 8 Mk 7 has now become obsolete' 

They have a sales enquiry form which seems to be at odds with those words.

Have a look yourselves HERE


By the way you grow daffodils from bulbs - _lamps_ are for providing light.


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## BobClay (Dec 14, 2007)

mmmmm ... that would explain why the breaker pulled out when I plugged that daffodil into the mains socket.


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## trotterdotpom (Apr 29, 2005)

"By the way you grow daffodils from bulbs - lamps are for providing light."

Not where I come from. In Australia they're known as "light globes" - fancy that!

John T


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## Mad Landsman (Dec 1, 2005)

trotterdotpom said:


> "By the way you grow daffodils from bulbs - lamps are for providing light."
> 
> Not where I come from. In Australia they're known as "light globes" - fancy that!
> 
> John T


I hope you mean the lamps and not the daffodil bulbs (?HUH)


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## trotterdotpom (Apr 29, 2005)

Mad Landsman said:


> I hope you mean the lamps and not the daffodil bulbs (?HUH)


No, that would be a "daffodil globe", but that's the way the artichokes.

John T


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## BobClay (Dec 14, 2007)

> 'After a long and distinguished career the AVOMETER® Model 8 Mk 7 has now become obsolete'


Interestingly there's a great demand on ebay for these fellahs. I bid on several of them before I landed one. If you think about it, the above quote applies to a lot of great British engineering. Maybe there's a message in that somewhere.


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## Mad Landsman (Dec 1, 2005)

Yes, I've just been scanning ebay - what you seem to get for £20 is, more often than not, incomplete, untested or spares / repair.


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## BobClay (Dec 14, 2007)

Patience is the only way to work on ebay. Keep bidding as they come and it will happen.


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## King Ratt (Aug 23, 2005)

Love my AVO which I have had for 40 years. And you can't switch a transistor with a digital meter either.
As to bulbs and lamps, bulbs grow - lamps glow, this being gospel according to an old Lecky friend of mine.


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## Shipbuilder (Jun 30, 2005)

This morning, wandering about our local giant car boot sale (Preston), I was wondering if I might find an AVO 8 as we had been talking about them. Hardly been there ten minutes when I saw this multimeter underneath a plaster squirrel. Took a chance and purchased it for £2. On getting it home, I was pleased to find it works perfectly. Someone had removed the batteries, so there is no corrosion. After I cleaned it up, it is in mint condition and I am very pleased with it. No indication of make, but it has Model Number C-7080EN on the dial. It measures 6.1 inches by 7.3 inches and is 3 inches deep. 
Bob


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## sparks69 (Dec 18, 2005)

I've got a roughservice BECKMAN one 9v battery change in 30 years !
bulbs - lamps only old purists would care...............


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## BobClay (Dec 14, 2007)

> No indication of make, but it has Model Number C-7080EN on the dial. It measures 6.1 inches by 7.3 inches and is 3 inches deep.


What I like about that meter is the size of the scale. Wow that was a good buy.


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## Roger Bentley (Nov 15, 2005)

*A Chinese Meter*

A popular place for shopping on my first tour in 1977 in Hong Kong was China Products and I could not resist buying this meter which reminded me of sea going days. It is built like the proverbial brick .... and I still use it on occasion today. Regards, Roger


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## BobClay (Dec 14, 2007)

I even considered carrying an oscilloscope at one time (back in the early days when such a piece of equipment was unheard of on a ship.) But that simply wasn't practical, and when I joined CP they provided a whole range of test gear.

Although nowadays you would probably be carrying a laptop and with a small interface box some of the scope software looks very impressive.


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## david.hopcroft (Jun 29, 2005)

When setting up a line-of-sight 7 gig microwave system locally, the commissioning engineer asked if I had an AVO back at the main site. He said it gave a far better indication of tuning than numbers in a scale. So I went and fetched our Avo 8 for him, but, as protocol demanded, I had to tell him that it was for 'indication only' because it was not 'calibrated' !! The machine required for an accurate measurement of the microwave frequency output was enormous, took ages to warm up and away for long periods for calibration.

David
+


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## SandyYoung (Sep 28, 2012)

This is bit like the argument about film -v- digital cameras. The truth is they both have their strong points and it all depends on what you are trying to do. 

Going into high impedance circuitry with an AVO can give readings which are nonsense. Likewise working on DC with an AC component will drive a digital meter nuts. And one of the main reasons for using something like a Fluke is that they usually survive being dropped. The later AVOs, as I remember, had less robust movements which did not appreciate being bumped.


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## Naytikos (Oct 20, 2008)

"Anchor Supplies" in Nottingham; used to be called Anchor Surplus. Huge dealers in ex military equipment, anything from an armoured car to a fuse, including test gear and tools.

I have both an AVO7 and 8 from them, bought some 15 years ago for, I think, £5 each. 
Similar to David's post 29, a local Cable & Wireless engineer borrowed one of them to measure the agc voltage whilst aligning a microwave link to another island.


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## Varley (Oct 1, 2006)

SandyYoung said:


> This is bit like the argument about film -v- digital cameras. The truth is they both have their strong points and it all depends on what you are trying to do.
> 
> Going into high impedance circuitry with an AVO can give readings which are nonsense.....


True, but consistently nonesense and so meaningful 'correct' values could still be listed fault finding charts for measurements taken with an AVO.

All I can repeat is that some of the most expensive incidents and effective assistances delivered have been down to appreciation of meter impedance by too few of the parties involved!

WT Radio Rules required carriage of a moving coil meter of better than (?) 25 Kohms per volt. I don't remember if this was developed into the digital era. (An old saying was the "The radio-room has tools by Act of Parliament. The engine room? By Act of God!").


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## J. Davies (Dec 29, 2010)

I still work at sea as ETO. Analog meters are better than digital in some cases. For example when measuring small voltages across data cable in the engine-room - a digital meter has such a high impedance that the noise on the lines show misleading readings. 

Also have you noticed how all switchboard meters, even on new ships, are still analog? Engineers like to see a swinging needle - they don't trust a digital display when it comes to kVar, V, A or kW.


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## sparks69 (Dec 18, 2005)

Birkits on the Strait in Lincoln had an AVO in the window for £25 last week.


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## retfordmackem (Aug 30, 2013)

Mad Landsman said:


> This thread got me thinking - I was given an AVO 8 years ago and when I got it home I discovered why - The idiot had let the batteries rot and it was useless.
> So I have just had look on the internet and Megger still list the AVO Model 8 Mk7 but with the words: 'After a long and distinguished career the AVOMETER® Model 8 Mk 7 has now become obsolete'
> 
> They have a sales enquiry form which seems to be at odds with those words.
> ...


Once again Malcolm another gem of wisdom.
Always be alert ,Britain needs lerts(BENNY HILL SHOW)


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## Mad Landsman (Dec 1, 2005)

retfordmackem said:


> Once again Malcolm another gem of wisdom.
> Always be alert ,Britain needs lerts(BENNY HILL SHOW)


Thank you, one tries one's best. 


As a postscript to this thread I was so inspired by it that I also found a fully functional AVO 8 Mk III on ebay for a reasonable sum. 
It now sits in my workshop to replace that old Oriental plastic analogue meter for those occasions when one needs a needle on a scale. 
I still mainly use the big yellow digital meter, with its little brother in the tool bag. 
(you can't test Hfe with an AVO - or can you?)


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## sven-olof (Jul 12, 2008)

Lot of good memories with AVOs . Beside more sopisticated instruments as Hp , Fluke , different DVM, fetvoltmeters etc at My desk I mostly used AVOS for transistor and diode faultfinding. Also when measuring currentflows in intermittent loads.
When climbing up in High towers I Always hoisted up My AVO with a Rope.

I have bougth some on internet for nostalgic reasons.


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## SparksG1714 (Oct 23, 2009)

Shipbuilder said:


> This morning, wandering about our local giant car boot sale (Preston), I was wondering if I might find an AVO 8 as we had been talking about them. Hardly been there ten minutes when I saw this multimeter underneath a plaster squirrel. Took a chance and purchased it for £2. On getting it home, I was pleased to find it works perfectly. Someone had removed the batteries, so there is no corrosion. After I cleaned it up, it is in mint condition and I am very pleased with it. No indication of make, but it has Model Number C-7080EN on the dial. It measures 6.1 inches by 7.3 inches and is 3 inches deep.
> Bob


Looks like a Taylor (?) But looking at the font style, think it's far east manufacture...

Didn't Avo 8 use a PP9? Tesco's have them, Maplins do a re-chargeable. There was a time when they couldn't be got anywhere though. We used to sell Russian made U-4313 20kΩ/V from Z&I Aero Services...


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## sparks69 (Dec 18, 2005)

Just to let you all know, my rough service Beckman has finally gone to meet its maker after many years of service. The Screen had gone totally black.
I'm now left with my £5 SANWA YX360TR analogue bought in Singapore around 1979.
There - I knew you would all be interested.


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## Mad Landsman (Dec 1, 2005)

SparksG1714 said:


> Didn't Avo 8 use a PP9?


No, it is a 15volt battery with terminal at each end. 

BLR154 is the official battery but if one can find a 15v battery for an old 'bulb' flash gun (B154) then you can buy an adapter frame to fit it. 

Alternative is to make your own with a stack of button cells, which conveniently come in boxes of 10. Silver Oxide are better but dearer and have a higher on-load voltage than cheaper alkaline.


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## Derek Roger (Feb 19, 2005)

Don,t use a megger on a thyristor ; it will blow it .


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## Varley (Oct 1, 2006)

Mad Landsman said:


> No, it is a 15volt battery with terminal at each end.
> 
> BLR154 is the official battery but if one can find a 15v battery for an old 'bulb' flash gun (B154) then you can buy an adapter frame to fit it.
> 
> Alternative is to make your own with a stack of button cells, which conveniently come in boxes of 10. Silver Oxide are better but dearer and have a higher on-load voltage than cheaper alkaline.


Be a bit careful of this from R-S:

526-6873 1 £7.03 £7.03 15V non-rechargeable battery,AVO meter.

The nipple height means that the metal casing of the battery is allowed in contact with the AVO 'brassiere' holder and so short it out.

Cut insulation tape with a hole for the nipple and all will be well.

Very noisy pots is the problem with mine otherwise a working art.


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## LucyKnight (Mar 27, 2013)

I purchased one about 20yrs ago from the local tip (wastesavers) for about £5 I noticed there was someone with a table full of them selling them at a amateur radio rally at Tavistock Devon in May. They were quite expensive and apparently he attends all the local radio amateur sales in this area. The next ones being at Hollesworthy and another at Harwood House Plympton end on November.


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## charles henry (May 18, 2008)

R651400 said:


> My guess this could be a Japanese made Micronta multi-meter marketed by Radioshack in the US and Tandy in the UK and probably carrying their brand names.
> Tandy I think was Realistic.
> Attachment is a later Micronta made in Korea.


Looks suspiciously like a copy of the American Simpson which I have used for the last 50 years. Whilst the Avon at the time worked well it was a big nonsensical "boat anchor" but the only one known in the UK.
Chas


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## BobClay (Dec 14, 2007)

Can't deny the Avo Minor was a poor effort. I remember having one of these on a ship (can't remember which one) and was seriously unimpressed. So I used to bum the lecky's avo when I needed it. I offered to swap, but his reply (to quote Judge Dredd) was 'unco-operative.'


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## Ron Stringer (Mar 15, 2005)

If only the radio station was on rental/maintenance from Marconi, an Avo Minor was supplied. If the radar was on r/m from Marconi, an Avo 7, later an Avo 8 was provided.

Generally the shipowner provided no meter at all.


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## NoR (Mar 24, 2008)

I bought the analogue meter in the pic about 27 years ago at Tandy in Paisley. As I recall it cost about £20. Bought it because I was wiring a small yacht and a meter of some sort was essential. It's done sterling service over the years although not really being a lecky or a sparks I haven't used half its functionality.


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## Ron Stringer (Mar 15, 2005)

R651400 said:


> Under Marconi contract would the shipowner be expected to provide?


As an R/O I frequently was asked to (and did) work on non-Marconi contracted equipment, for which the shipowner provided neither tools nor spares in most instances. Decca radars were more commonly carried than Marconi radars, even where the radio station was on contract from Marconi.


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## cajef (Feb 8, 2012)

Ron Stringer said:


> for which the shipowner provided neither tools nor spares in most instances. Decca radars were more commonly carried than Marconi radars,


The spares for Decca Radars were only provided if the shipowner paid extra for them, they were supplied in excellent wooden boxes with carry handles and all the corners had metal protectors on, the small ones were much prized by us Decca engineers as toolboxes while the larger ones were used by the depots to keep and carry spares when out servicing vessels.


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## Ian Beattie (Mar 28, 2013)

I remember being on one ship where the radar installation was BTH (British Thompson House or is it Houston)- I was unaware they made radars, this was a very big beastie indeed, much larger than anything I'd seen before. After being shown round it I was very relieved that this was apparently the domain of the second mate. Just why the shipping company did this I've no idea and neither did the 2/O as he knew absolutely zilch about radio never mind radar. Its too long ago to remember which shipping line it might have been (could it have been RML ?) Must try and find my discharge book somewhere in the loft groan !!


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## Ron Stringer (Mar 15, 2005)

Ian Beattie said:


> I remember being on one ship where the radar installation was BTH (British Thompson House or is it Houston)- I was unaware they made radars, this was a very big beastie indeed, much larger than anything I'd seen before.


The initial letters of British Thomson-Houston radars were reputed, by shore technicians & radio officers alike, to stand for Big, Thick and Heavy.


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## Ian Beattie (Mar 28, 2013)

Ron tbat sounds about right I just remember it taking up an inordinate amount of space three or four times that of any other radar but I think the actual screen was around nine or ten inches wide - still cant remember what ship it was quite frustrating,
Cheers Ian


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## david.hopcroft (Jun 29, 2005)

It was a walk from the wheelhouse passed the Radio Room to the Radar room where the BTH RMS2 'beastie' was housed. You had to lean around an open door to tune it. Couldn't get it to stay tuned once, and in my haste, forgot to dog down the door. It slammed shut while I was hot footing it back to the bridge. 'That's it' cried the 2nd Mate. Who was I not to turn down a few brownie points !!

David
+


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## Wismajorvik (Dec 29, 2011)

I completed a course on BTH radar at Leicester late '64 and never saw one again. Similar story S G Brown gyro (Watford), and Magnavox Satnav, (possibly at Muirheads?). Completed a course on Raytheon Radar, (in Copenhagen) in Oct'71 and didn't come across one for eight years...Good times.


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