Hello Rick, I hesitated to give an advice for a good programmer for some reasons, sorry for being late, now. I also bought the latest TL866II plus, from the original manufacturer, which I can highly recommend for more recent non volatile components. There's a long history behind this programmer, as older versions like the CS had been copied by other Chinese ..uum.. garage companies, I assume.. therefore the original manufacturer XGECU terminated all these older versions some time ago, so I hope your CS version is  'compatible', or 'old stock', or you should make sure it is anything of both, before attempting to make a firmware update.. as far as I remember.. there's been a long discussion on eevblog about this programmer, and stuck FW updates, especially on clones. Best is to avoid these updates, anyhow. The 2nd problem with the recent version which I have is, that it is not able to program very old EPROMs which require high programming voltages like 25V or even 21V, (I didn't test that yet on my old stock), so your EPROMs might fall into this category.. and if the CS version (either compatible or original) is still able to program one of these, I don't know. The operating software will tell, hopefully, otherwise the eevblog thread. So my recommendation is, to carefully check the type of your old EPROMs. I strongly assume that you will be able to safely read their content. But you should order compatible newer EPROMs, OTPs, or FLASH parts, which the programmer can handle for sure, i.e. search inside its parts library, please. Frank