Good call on the HP 34401A. Did a quick eBay search and found what I have always seen. Below $600 these DMMs are pretty banged up w/ no gaurantee of function beyond the sellers, "fully functional" which means nothing. At $650+ they seem to get a lot better but again $100 more dollars and I am buying a new DMM from a different manufacturer w/ warranty.
I have got one from eBay recently for 200 euro, with cal valid until mid-2017. The only issues were a slightly dim, but still usable display (easy to replace, there are Chinese sellers for the replacement VFDs for about $50 or you can get the original HP display front panel module too) and cracked rear plastic bezel (easily glued together). It wasn't even dirty, at least nothing a moist rag wouldn't clean right off. The seller had another exactly like that, both coming from some measurement rack.
It was this guy and he has another one of these meters for sale, it seems:
http://www.ebay.fr/itm/Hewlett-packard-34401-A-multimeter-multimetre-/152397401215He has 100% feedback, including from sale of several of these meters, so I would believe him that the meter is OK (and mine certainly has been).
So don't dismiss these, you can certainly find a cheap one in decent shape these days. Keysight has stopped supporting them last December, so companies are replacing them with newer models and they are thus available for little money. They just tend to get snapped up quickly.