USB EPROM readers?...

[Rax]

What are some good ones y'all have found reliable and not prone to damage precious calibration data and other goodies?

I'm particularly interested in affordable ones available on the US market.

I'd use this to backup the NVRAM of a Prema 6048.

[alm]

I have the Mcumall GQ-4X (not the newer GQ-4X V4 or GX-4X4) and the TL-866CS (now replaced by the XGecu T48). I have not done any serious comparison, but my impression is that the GQ-4X is more reliable, but that the TL-866 supports more devices. I'll grab the GQ-4X first and only if it doesn't support it do I grab the TL-866.

But most people seem to be perfectly happy with the TL-866/T48 series.

[Micke]

I have a TL-866, but for the same reason as you, I did not want to risk accidents with EPROM:s from precious equipment, and besides I needed a programmer that could program old 2716 with 25V VPP.
I bought a german Batronix BX32P Barlino II https://www.batronix.com/shop/programmer/BX32P/index.html
The software is good, and has good chip support: https://www.batronix.com/files/pdf/BX32PBarlino-II-DeviceList.pdf
I am very happy with it! 

[nfmax]

I also have a Batronix Barlino II, and I second the recommendation!

[m k]

I have TL866CS, it couldn't read something that self made replicator finally had no problems.
(verdict was weak bits)

[alm]

besides I needed a programmer that could program old 2716 with 25V VPP.

The XGecu T48 is also said to support up to 25V VPP. The original TL-866 was 21V, the successor TL-866 II 18V and the current T48 25V. Note that for anything but DIP you'll need adapters. They are not necessarily compatible across programmers. For example the GQ-4X has their own series of adapters which sometimes contain a bit of logic, while the TL-866 uses pretty much all simple pin adapters.

[Shock]

There are a few hardware hacks to give the TL-866 25V support, but it's discontinued anyway unless you are ok with a knockoff. Dirt cheap though and easily repairable so even as a project or a sanity check worthwhile.

[Rax]

It seems to me the typical xGecu kit, without any adapters, can accommodate any/most DIP ICs, is that correct? I am thinking of grabbing one like that, and only getting adapters if/when the need arises. I'd initially really need it to read the memory off of a 48Z02 (DIP 24, I think), and save calibration settings.

How about software? Reliably non-destructive?....

[alm]

Yes, you can read pretty much any DIP chip except with more pins than the ZIF socket: there are adapters for some programmers for that. The chip support list, like the chip support list for the GQ-4X programmer, will usually say if you need an adapter.

While I find the Mcumall software easier to use with better labeled buttons than the Tl-866 software, the buttons to read and write are quite distinct and I've not had a problem confusing them.

[fenugrec]

What are some good ones y'all have found reliable and not prone to damage precious calibration data and other goodies?

If you're really, really concerned about damage, a "passive" dump with a logic analyzer is hard to beat (at the cost of more work, and possibly an incomplete dump if the firwmare doesn't systematically read all locations, for e.g. a power-on CRC test).

For less stressful situations I've been using a tl866-II successfully for a few years. Only had one weird situation where an EPROM would fail the Chip ID validation with a troubling "pin detect error"; it could still be read just fine with the ID check disabled.