Daniel Bailey from Bit Of A Hack did a repair of a digital Avometer DA116 and documented the whole process on his blog:
Anyway, this post is about my AVO DA116. I did this repair a while ago and almost forgot to post about it. I bought a broken AVO DA116 from ebay. For those who don’t know; AVO made a few digital multimeters before the name AVO went away. So far I have three digital AVOs. I now have two of them fully working, the other uses nixie tubes and still needs fixing.
Full details at Bit Of A Hack site.