Setting MK3 MK4 Avometers for transit. - UK Vintage Radio Repair and Restoration Discussion Forum

DPUGH72 · 11th Apr 2018, 9:23 pm

How can you set the earlier Avometers switch positions for transit? On the mark 5 it says switch to DC and Off position so it is heavily damped for transit. So what can be done to help earlier AVO's for transit, as I carry my mk4 around in my car when I do some auto electrical work. I read somewhere that some earlier AVO's were damaged in transit.

Colinaps · 11th Apr 2018, 11:10 pm

I'd set it to a mA range and short the terminals. Try it and see if the needle is damped when you rock the meter from side to side.
Cheers,

Colin.

12th Apr 2018, 8:31 am

Isn't it done by setting the switches to DC and AC?

barrymagrec · 12th Apr 2018, 9:04 am

That was certainly the case for an 8 MkII, I always assumed other models are the same.

The Philpott · 12th Apr 2018, 9:39 am

I only have the 8/III and 9/II (which are 1960's era.)

On these, one sets the meter to 'DC' and '50uA' then securely short the main + and - terminals. (I use a length of copper from a bit of Pirelli mains cable, bent in a suitable curve with hooks at either end; this gives you flexibility and can be reused indefinitely) The less sensitive the meter the less the damping effect of this method.

Merely setting the selectors to 'DC' and 'AC' on these earlier models does nothing for the safety of the meter in transit.

As regards the later model 8's, I believe the transit problem was addressed and there IS a setting which damps the movement (Probably AC and DC but don't take my word for it)

Dave

Sinewave · 12th Apr 2018, 11:54 am

It's an interesting one which I've always wondered, as with the 8 Marks 5, 6 and 7, the left switch to off and the right to DC does heavily dampen the movement.

I'm going to have to experiment with some of the earlier ones now to see if this works with them.

The Philpott · 12th Apr 2018, 12:00 pm

I too carry one or more 'oldies' for automotive use, satisfactorily tested passive ABS sensors and crank sensors, but Lambda sensors are a no-no, a much more sensitive DMM with a good sampling/refresh rate is required, or ideally a 'scope.

The older and less sensitive avo's can't really be damped as far as i know, but having said that I have only hand one fail in transit, and that was a universal avominor. One of the hair springs had become detached, but I can't really draw any conclusion/s as it was a skip recovery item and had had a very hard time before I salvaged it.

The Philpott · 12th Apr 2018, 12:04 pm

Ah yes, Mk5 onwards you set to OFF and DC, now I remember.

The earlier method I mentioned is likely to be the one to use with the mk4.

Dave

DPUGH72 · 14th Apr 2018, 8:54 am

Yes that works when on DC and 50 microamps. Needle nicely damped, Thanks all.

I made a short wire with a banana plug each end to go between both + and - terminals. Will work nicely for when I'm carrying the meter around.

Sinewave · 17th Apr 2018, 8:55 pm

I've just tried this on one of my Avo 8 Mk1 units and am pleased to say that it works.

11th Apr 2018, 9:23 pm	#1
DPUGH72 Triode Join Date: Apr 2018 Location: Llandrindod Wells, Powys, Wales, UK. Posts: 10	Setting MK3 MK4 Avometers for transit. How can you set the earlier Avometers switch positions for transit? On the mark 5 it says switch to DC and Off position so it is heavily damped for transit. So what can be done to help earlier AVO's for transit, as I carry my mk4 around in my car when I do some auto electrical work. I read somewhere that some earlier AVO's were damaged in transit.

11th Apr 2018, 11:10 pm	#2
Colinaps Pentode Join Date: Jul 2009 Location: Roxburghshire, UK. Posts: 196	Re: Setting MK3 MK4 Avometers for transit. I'd set it to a mA range and short the terminals. Try it and see if the needle is damped when you rock the meter from side to side. Cheers, Colin.

12th Apr 2018, 8:31 am	#3
Guest Guest Posts: n/a	Re: Setting MK3 MK4 Avometers for transit. Isn't it done by setting the switches to DC and AC?

12th Apr 2018, 9:04 am	#4
barrymagrec Octode Join Date: Dec 2017 Location: Morden, Surrey, UK. Posts: 1,557	Re: Setting MK3 MK4 Avometers for transit. That was certainly the case for an 8 MkII, I always assumed other models are the same.

12th Apr 2018, 9:39 am	#5
The Philpott Dekatron Join Date: Aug 2016 Location: Colchester, Essex, UK. Posts: 4,106	Re: Setting MK3 MK4 Avometers for transit. I only have the 8/III and 9/II (which are 1960's era.) On these, one sets the meter to 'DC' and '50uA' then securely short the main + and - terminals. (I use a length of copper from a bit of Pirelli mains cable, bent in a suitable curve with hooks at either end; this gives you flexibility and can be reused indefinitely) The less sensitive the meter the less the damping effect of this method. Merely setting the selectors to 'DC' and 'AC' on these earlier models does nothing for the safety of the meter in transit. As regards the later model 8's, I believe the transit problem was addressed and there IS a setting which damps the movement (Probably AC and DC but don't take my word for it) Dave

12th Apr 2018, 11:54 am	#6
Sinewave Octode Join Date: May 2016 Location: Oxfordshire/Bucks borders, UK. Posts: 1,604	Re: Setting MK3 MK4 Avometers for transit. It's an interesting one which I've always wondered, as with the 8 Marks 5, 6 and 7, the left switch to off and the right to DC does heavily dampen the movement. I'm going to have to experiment with some of the earlier ones now to see if this works with them. __________________ Avometer, vintage Fluke and Marconi collector. Also interested in vintage Yaesu and KW.

12th Apr 2018, 12:00 pm	#7
The Philpott Dekatron Join Date: Aug 2016 Location: Colchester, Essex, UK. Posts: 4,106	Re: Setting MK3 MK4 Avometers for transit. I too carry one or more 'oldies' for automotive use, satisfactorily tested passive ABS sensors and crank sensors, but Lambda sensors are a no-no, a much more sensitive DMM with a good sampling/refresh rate is required, or ideally a 'scope. The older and less sensitive avo's can't really be damped as far as i know, but having said that I have only hand one fail in transit, and that was a universal avominor. One of the hair springs had become detached, but I can't really draw any conclusion/s as it was a skip recovery item and had had a very hard time before I salvaged it.

12th Apr 2018, 12:04 pm	#8
The Philpott Dekatron Join Date: Aug 2016 Location: Colchester, Essex, UK. Posts: 4,106	Re: Setting MK3 MK4 Avometers for transit. Ah yes, Mk5 onwards you set to OFF and DC, now I remember. The earlier method I mentioned is likely to be the one to use with the mk4. Dave

14th Apr 2018, 8:54 am	#9
DPUGH72 Triode Join Date: Apr 2018 Location: Llandrindod Wells, Powys, Wales, UK. Posts: 10	Re: Setting MK3 MK4 Avometers for transit. Yes that works when on DC and 50 microamps. Needle nicely damped, Thanks all. I made a short wire with a banana plug each end to go between both + and - terminals. Will work nicely for when I'm carrying the meter around.

17th Apr 2018, 8:55 pm	#10
Sinewave Octode Join Date: May 2016 Location: Oxfordshire/Bucks borders, UK. Posts: 1,604	Re: Setting MK3 MK4 Avometers for transit. I've just tried this on one of my Avo 8 Mk1 units and am pleased to say that it works. __________________ Avometer, vintage Fluke and Marconi collector. Also interested in vintage Yaesu and KW.