My parents bought this Avometer for me at a boot sale when I was most likely still in primary school. It didn’t work, of course. But it’s a neat piece of kit.
I remembered about it again the other day and went to find it in the attic where I do quite a bit of stowing.
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A few decades worth of dirt.
Some cleaning and some googling and…
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Hey! It’s a year older than I am (366 = March 1966).
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I’ve never even seen one of the 15V batteries for sale anywhere, so these batteries have been in here since before I got the meter. And most of the time I’ve had it was spent in a hot attic. The batteries are flat, of course, but I would have expected things to look a whole lot worse.
Now I distinctly remember that I tried to find out what’s wrong with this meter, and at the time I concluded that the movement was not working. Well, it turns out that there’s nothing wrong with the movement. This is great news. Anything else is easier to fix than a d’Arsonval movement.
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Here’s the damage. This is the 42.2 ohm resistor between the 10mA and 100mA taps on the DC switch (see the schematic at the end of the user manual) and I would say that it’s maximum power rating was exceeded…
I will see whether I can find or make or devise a replacement*, and I’ll clean up the outside.
Please, if you have one of these, be nice to it, don’t gut the insides like this poepol did.
* Believe it or not, 42.2 Ohm is an E96 value, but I might need a higher wattage and I’d probably end up putting ten 422 Ohm 1% resistors in parallel. Edit: Six 470 ohm, six 560 ohm, and one 4k7 in parallel makes 42.2065 which is good enough for me.
(Edit: link to balancing the movement)