Avometer model 40 - UK Vintage Radio Repair and Restoration Discussion Forum

rockinmark · 25th Mar 2020, 6:52 pm

Hi I was out for my once a day exercise and came across a avometer model 40 I dont no anything about these I checked the batteries and changed the 1.5 aa then checked the voltage of a battery and a resistor on the meter seemed to work

I know nothing about them or how to use one. Would anyone have a manual for it so I can find out more and learn how to use it properly and find out about the q

Mark

The Philpott · 25th Mar 2020, 7:13 pm

You may find images if you search on here; many of the manuals have been scanned on by forum users.

If not send me a private message and i will email images to you at the weekend.

The critical thing is to pay full attention when using the meter as (despite the cut-out) they are vulnerable to overload, reverse polarity mistakes, and impact. The voltage ranges on a Model 40 are less than ideal by the standards of today, but they can be surprisingly accurate.

Dave

chriswood1900 · 25th Mar 2020, 7:42 pm

Useful info here http://www.richardsradios.co.uk/avo40.html and here https://www.vintage-radio.net/forum/...ead.php?t=2804
and use the instructions for a Model 7 which will be a good guide.

Superscope · 25th Mar 2020, 9:13 pm

Hi,

Model 40 Mk II working instructions attached.

Operation would be pretty much the same for the Mk I.

Ian

rockinmark · 25th Mar 2020, 10:48 pm

Thanks for that Ian I will print it and have a good read

rockinmark · 26th Mar 2020, 12:04 am

Reading the manual And what buttons do.
The ÷2 button doesn't move, should it be like a button or would it be stuck

Mark

The Philpott · 26th Mar 2020, 12:54 am

It's mildly spring loaded so, yes, it should move in for low V/A ranges and spring back out for high V/A ranges. (ie it doesn't rotate)

rockinmark · 26th Mar 2020, 3:59 pm

Ok so maybe mines stuck in then thank

rockinmark · 26th Mar 2020, 6:28 pm

I have now had a better look at it I have taken it apart to see if I could ease the ÷ button in and out to see if it would work the date inside says 1969 so I would presume that that was its last calibration there is a date for 68 as well. After taking it from its case I noticed that the P adjuster has a crack so when you turn it the brass bit doesn't stay straight that explains why at different point it would shoot to 0 still it was free maybe in the future I will look for another one

Thanks for the help
Mark

The Philpott · 26th Mar 2020, 11:26 pm

A very small amount of 3 in 1 can ease the button where bakelite rubs against bakelite. It's feasible that a piece of grit might have jammed it, it is inaccessible from behind until the meter movement is removed- (a search on the forum will produce precautions/instructions for this.)

25th Mar 2020, 6:52 pm	#1
rockinmark Heptode Join Date: Sep 2014 Location: St Albans, Hertfordshire, UK. Posts: 594	Avometer model 40 Hi I was out for my once a day exercise and came across a avometer model 40 I dont no anything about these I checked the batteries and changed the 1.5 aa then checked the voltage of a battery and a resistor on the meter seemed to work I know nothing about them or how to use one. Would anyone have a manual for it so I can find out more and learn how to use it properly and find out about the q Mark Attached Thumbnails

25th Mar 2020, 7:13 pm	#2
The Philpott Dekatron Join Date: Aug 2016 Location: Colchester, Essex, UK. Posts: 4,106	Re: Avometer model 40 You may find images if you search on here; many of the manuals have been scanned on by forum users. If not send me a private message and i will email images to you at the weekend. The critical thing is to pay full attention when using the meter as (despite the cut-out) they are vulnerable to overload, reverse polarity mistakes, and impact. The voltage ranges on a Model 40 are less than ideal by the standards of today, but they can be surprisingly accurate. Dave

25th Mar 2020, 7:42 pm	#3
chriswood1900 Octode Join Date: Jan 2007 Location: Dorridge, West Midlands, UK. Posts: 1,481	Re: Avometer model 40 Useful info here http://www.richardsradios.co.uk/avo40.html and here https://www.vintage-radio.net/forum/...ead.php?t=2804 and use the instructions for a Model 7 which will be a good guide. __________________ Chris Wood BVWS Member

25th Mar 2020, 10:48 pm	#5
rockinmark Heptode Join Date: Sep 2014 Location: St Albans, Hertfordshire, UK. Posts: 594	Re: Avometer model 40 Thanks for that Ian I will print it and have a good read

26th Mar 2020, 12:04 am	#6
rockinmark Heptode Join Date: Sep 2014 Location: St Albans, Hertfordshire, UK. Posts: 594	Re: Avometer model 40 Reading the manual And what buttons do. The ÷2 button doesn't move, should it be like a button or would it be stuck Mark

26th Mar 2020, 12:54 am	#7
The Philpott Dekatron Join Date: Aug 2016 Location: Colchester, Essex, UK. Posts: 4,106	Re: Avometer model 40 It's mildly spring loaded so, yes, it should move in for low V/A ranges and spring back out for high V/A ranges. (ie it doesn't rotate)

26th Mar 2020, 3:59 pm	#8
rockinmark Heptode Join Date: Sep 2014 Location: St Albans, Hertfordshire, UK. Posts: 594	Re: Avometer model 40 Ok so maybe mines stuck in then thank

26th Mar 2020, 6:28 pm	#9
rockinmark Heptode Join Date: Sep 2014 Location: St Albans, Hertfordshire, UK. Posts: 594	Re: Avometer model 40 I have now had a better look at it I have taken it apart to see if I could ease the ÷ button in and out to see if it would work the date inside says 1969 so I would presume that that was its last calibration there is a date for 68 as well. After taking it from its case I noticed that the P adjuster has a crack so when you turn it the brass bit doesn't stay straight that explains why at different point it would shoot to 0 still it was free maybe in the future I will look for another one Thanks for the help Mark

26th Mar 2020, 11:26 pm	#10
The Philpott Dekatron Join Date: Aug 2016 Location: Colchester, Essex, UK. Posts: 4,106	Re: Avometer model 40 A very small amount of 3 in 1 can ease the button where bakelite rubs against bakelite. It's feasible that a piece of grit might have jammed it, it is inaccessible from behind until the meter movement is removed- (a search on the forum will produce precautions/instructions for this.)