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Old 22nd Jun 2024, 10:52 am   #1
Craig Sawyers
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Default AVO Meter Instruction Plate.

Not quite sure where to post this - it relates to the instruction plate on the back of AVO 8's. My AVO8 MkII rear plate was in a shocking state, faded lettering, scuff marks, and the feet were quite badly rotted or at best scuffed almost off.

So why restore? Well in spite of its being November 58 build, it is ridiculously accurate still, within a meter needle width from input from my Fluke calibrators.

First thing was the backplate lettering and black borders. I did that by laboriously replicating the font size, line spacing etc to most closely replicate the panel lettering. I used Arial, that being closest to the AVO font. Then I reproduced the border in a CAD package (LibreCAD), printed it out, stuck the lettering on, scanned it, and edited out any odd artefacts in MS Paint. After lots of checking, I printed it onto Laser printer Waterslide sheets.

I then removed the original remaining lettering and paint (it was pale yellow all the way down), primed and spray painted with Rustoleum Antique White (a pale yellow). B&Q.

Three attempts later, I got the water slide right, and it looks absolutely great.

Now to the feet. The originals were 1/2" diameter and 1/4" tall, with a metal washer, and were made of a soft rubber.

I tracked these guys down in the US, and when delivered are identical in size, hole size and stickiness of the rubber https://www.rubberfeetwarehouse.com/...-feet-recessed . The most expensive bit is of course the shipping! But they are identical to the original AVO8 feet.

Attached file is a jpg, and in the next message an image of the finished plate, just waiting for a protective spray coat.

If you want to use the jpg to print to waterslide paper, make sure you use Transparent rather than White, and print at 100%. Print using laser or ink jet paper as appropriate, and print in black and white. I used laser paper.

The alignment feature is the mounting holes at the top of the plate, and make sure the plate is wet first so you can slide the image enough to get the border symmetrical each side.

Craig
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Old 22nd Jun 2024, 11:01 am   #2
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Default Re: AVO Multimeter survey

I've just tried printing from the attachment above, and it is awful - too small and too low resolution.

The actual jpg is around 3.5MB. So if you want that, pm me your email address and I'll send it.

Craig
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Old 22nd Jun 2024, 11:13 am   #3
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Default Re: AVO Multimeter survey

OK - images of the original panel, and the finished version.

Craig
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Old 22nd Jun 2024, 11:21 am   #4
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Default Re: AVO Multimeter survey

Messing up the images - second try!
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Old 22nd Jun 2024, 6:29 pm   #5
The Philpott
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Default Re: AVO Multimeter survey

That does the job, doesn't it? Just as well these versions have a removable instruction plate, earlier ones are riveted on!

There were some original feet on ebay in recent times, all gone now.

Forum user Ti Pwun specialises in 3D printing however, he may have created a file for these particular feet.

Dave
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Old 22nd Jun 2024, 6:59 pm   #6
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Default Re: AVO Multimeter survey

I actually bought 30 feet, a quid each, and £19 shipping, so £1.63 each, which I did not think was bad all round.

I also bought some 3mm diameter aluminium rivets. One foot is screwed on (the screw insert is behind the battery box).

I temporarily fitted the two other feet with screws and nuts. The problem is that the nuts are very close to the AVO itself when it is in its case. Which is why AVO used rivets for the two lower feet, and then stuck on thin SRBP insulation so the complete assembly would pass the 6,000Vac flash test (presumably from any terminal to a metal plate on which the AVO sits).

Craig
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Old 22nd Jun 2024, 7:44 pm   #7
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Default Re: AVO Meter Instruction Plate.

Yes indeed, there's very little clearance between the foot fixings and certain live parts of the meter. The length of the casing screws also has to be checked as one that is too long can be perilously close to certain rotary selector wiper contacts.

The SRBP patches used in the rear of the case are usually stuck on with black (stockholm?) tar which isn't actually very sticky. I usually clean it off with wd40 and use Araldite instead.

The original avo feet are composite insofar as they have a layer of fabric to avoid being torn past the rivet head if the meter is dragged. Shouldn't be a problem for you as they're treated with more respect now than they were in the last century..

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Old 3rd Jul 2024, 11:19 pm   #8
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Default Re: AVO Meter Instruction Plate.

Here's some images of the final restoration of my 1958 Mk2. I used aluminium rivets, 3mm diameter. The originals were 1/8" diameter steel, but aluminium is much easier to peen over.

They were slightly long, so I cut them to length, then used my smallest centre drill to make a hole in the centre. That was easy to peen over using a centre punch.

I then used two layers of 0.2mm thick fiberglass, 25mm square, and attached them over the rivets using T7000 (see https://www.vintage-radio.net/forum/...78&postcount=5 ).

Images attached, including the finished back.

Craig
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Old 4th Jul 2024, 10:34 am   #9
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Default Re: AVO Meter Instruction Plate.

Very nicely done Craig. This meter is obviously important to you.

At various times Avo, and before that ACWEECO use various metals for the instruction plate rivets. During the Second World War era, copper was common; it probably just depended on which materials were available and allocated at the time.

Don't forget to smear some debris catching grease in the insdie of the case, preferably old Avo perfume!

PMM
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Old 4th Jul 2024, 2:02 pm   #10
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Default Re: AVO Meter Instruction Plate.

Double sided tape. Very very sticky indeed.

Craaig
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Old 4th Jul 2024, 2:05 pm   #11
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Default Re: AVO Meter Instruction Plate.

Quote:
Originally Posted by pmmunro View Post
Very nicely done Craig. This meter is obviously important to you.


PMM
First AVO 8 I owned, inherited from a Southampton University clear out in 1976. Hence wanting to restore it to its original glory.

Craig
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Old 4th Jul 2024, 2:34 pm   #12
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Default Re: AVO Meter Instruction Plate.

Very impressive Craig. A job well done.

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Old 4th Jul 2024, 3:05 pm   #13
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Default Re: AVO Meter Instruction Plate.

After applying the water slide sheet to the panel, did you lacquer over it (or leave as-is)? If lacquer - what did you use? I'm interested as I am thinking of using this process to restore a panel on a record deck.
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Old 4th Jul 2024, 3:27 pm   #14
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Default Re: AVO Meter Instruction Plate.

Job done. Very easy to chip the bakelite when peening over little rivets.

Glad the feet went well. I once acquired an Avominor for which a previous owner had made rather a nice wooden box. The dimensions were based on a meter with worn down feet however, and when replaced with great new 3d printed ones, the box had to be adapted (ie 4 divots dug in the wood!)

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Old 4th Jul 2024, 4:47 pm   #15
Craig Sawyers
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Default Re: AVO Meter Instruction Plate.

Quote:
Originally Posted by cooperman View Post
After applying the water slide sheet to the panel, did you lacquer over it (or leave as-is)? If lacquer - what did you use? I'm interested as I am thinking of using this process to restore a panel on a record deck.
I used PlastiKote Clear Sealer Acrylic

https://www.amazon.co.uk/dp/B006O6D8...t_details&th=1

I've used this stuff before on waterslide decals, and the waterslides I use said acrylic spray is compatible. The previous can, not used for a number of years and nearly full, had a blockage in the can (not in the spray head), so I had to buy a new can.

Several light layers, and then a couple of days to get really hard (use a sniff test - once it stops smelling, it is hard).

Craig

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