Who wants the accuracy?
And they DO come equipped with lots of rangers.
They're also far more difficult to read
Which is seldom necessary.
But for seeing the direction and rate of change of some things
But probably more shockproof.
In message , Arfa Daily writes
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.
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.
Indeed - and can survive being dropped. And fit in the pocket.
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.
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.
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.
Which was normally specified on the schematic.
In the case of one of mine, without showing a bulge. It's 5mm thick, and autoranges.
So, basically, you're saying use the appropriate meter for the job.
Ian Field explained :
They are still available, but many simply make up a holder to stack button cells to the value of 30v.
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
Send it to a good home then, Dave. Want my address ? :-)
Arfa
Yep. Been to all those places Ian. Thanks anyway
Arfa
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
The site has links to viewers: see eg
...As the actress said the the bishop, stirring her tea...
In message , Arfa Daily writes
Ah! The Mk 4 is an AVO Multiminor - not an Avo 8. Sorry!
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.
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
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