HP-28S with User and Advanced Reference Manuals

[jebem]

Thanks for your explanation, Bob.

I guess that there are very large quantities of these machines in the market and it helps to lower the market value a bit as well.

In 2014 I bought one pristine, almost new in the box, complete with manuals (although in Brazilian Portuguese language edition) HP-28S for just 40 Euros.

The original owner paid 31260$00 Portuguese escudos in 1991 (about 160 Euro) from a HP dealer in Porto city.

I don't even try to insert batteries in it because I know the battery door can break at any moment, even if it was rarely used before. If it breaks, its value will be close to zero these days.