When I opened the HP 8903B Audio Analyzer I realized, that the rom memory on the processor board is assembled from various chips from various providers, what I not really like. The EPROMs anyway need reprogramming after a few decades, to keep the instrument working in stability.
As I didn't want to erase the originals, I had the plan to create a complete new EPROM set. The 2716 and 2516 EPROMs are not available anymore from any of the regular suppliers. So I went to the eBay to find some. Ordered 20pcs. Arrived from China:
I know, that the manufacturers time to time change the process of the devices kept on the market. But come one! Three different chip size, with the same date code?
Guys, you can do better job than this! :-D
Anyway, I tried. One out of the twenty acted like an EPROM in the programmer, even this one was failing during the programming cycle.