Sunday 14 April 2024

XGeco Pro / TL866 II Plus (not a Mini Pro) Repair

This is the EPROM programmer I use the most these days. This has programmed all the EPROMs for all the Minstrel and Mini PET kits, PET ROM/RAM boards and pretty much everything else I have touched.

Although that is an old photo, taken when I got it 5 years ago.

I still refer to this as a Mini Pro, although that was the first revision, I had one of those, and I got this to replace that when it was getting a bit tired. 

This is the second revision, the XGeco Pro according to the top moulding, the TL866 II plus according to the label.

These days it is a little worse for wear, and it keeps popping the top of the ZIF socket. The screw threads are unfortunately stripped.

I can push it back down, and hold it to keep it working, but it's days are numbered.

These look to be Chinese rip offs of the original 3M Textool sockets. Often labelled up (if you look closely) as "3N Textdol" or other variations of that.

I think the originals used a nut and bolt arrangement, rather than the self tapper into plastic seen here, but this one has done very well with probably tens of thousands of chips.

I am not sure if the original 3M Zif sockets are still in production, all I could find for sale on Digi Key were the same Chinese rip offs sold via Adafruit, which is a little worrying. (the marketplace on DigiKey seems to be infected with loads of Ali Express knock off "new old stock" black topped scrap ICs .... but that's a rant for another day)

Time to replace the socket, and I'd rather not use another one of those, so I have an older but very much still functional Aries socket of much better build quality.

This also has thin pins, so I can fit a socket to enable it to be easily replaced in future.

The blue ones have wide pins that don't fit into turned pin sockets, you have to wedge them into cheap style IC sockets or solder them direct.

I often end up making stacks of a blue ZIF socket wedged into a dual wipe IC socket pushed into a turned pin socket.

Handy to easily swap those in and out with just a normal IC.

There were three of them in the Penultimate +2 development board.

Time to take this thing apart and replace the ZIF socket.

Inside the case, there are two PCB stacked together. Mostly via dual row headers, but also via two soldered ground connections.

With those two pins desoldered, the stack can be split up.

The bottom board has the voltage regulators, and underneath the main microcontroller (with the number scratched off).

With the ZIF socket desoldered, the top board is mainly IO expanders and switching transistors.

And the same on the back. Including four good old 75HC595s shift registers.

I have fitted an IC socket, so I can swap ZIF sockets without having to dismantle it again in the future.

With the IC socket fitted, the layers can be reassembled and it can be put back in the case.

I ended up adding a second IC socket to raise the ZIF socket up higher as there was a notch at the back of the new ZIF socket that hit the case, and I didn't want to modify the case (or the socket).

And there we go, reassembled with the new(ish) ZIF socket.

And that tests out fine. Ready to program ROMs and microcontrollers for the next batch of Minstrels or Mini PETs or whatever I dream up next.

I should probably get around to ordering a new one, just in case. They are now onto the third generation, the T48, which now comes in a black case, with that looks like that same type of ZIF socket as this.

It has always been a little difficult with these as XGecu don't seem to have an official UK outlet. So you are left to buy from ebay or Amazon, and take a risk that some of these are fakes. This was particularly a problem with the early Mini Pro, but less so these days. Although some of the listings have photoshopped out the XGeco branding (or maybe have their own case without it?). Either way, I am avoiding the ones that do not explicitly say "XGeco T48".

Looking through Amazon, the price and accessories vary quite a bit, although I am not sure this is quite the T48 I was looking for.

You may ask why I am looking for a new one at all, haven't I just fixed the old one? Well, having that be flaky reminded me how much I use and rely on that, so having a backup would probably be a good idea, and the new one supports more devices, which might come in handy at some point, particularly if support for the old one is dropped.

Roll forward a couple of days and the T48 has arrived. Looks to be a genuine one.

All very nice.

Turns out the new one uses the same ZIF socket arrangement as I chose to repair the older one, including a turned pin IC socket to allow it to be changed in future.

The new programmer is supported by the same software as the old one, which detected the device correctly and updated the firmware on first use.

Both being supported by the same software means I can make use of the multi-program option, and program multiple devices at once. One in the old TL866 II Plus, and one in the new T48.

However, one thing I did not expect. They have reversed the position of the target device in the new programmer.

Pin 1 is now at the LED and USB connector end, the opposite end to the ZIF socket handle, which was pin 1 on the old programmers.

That might take a bit of getting used to, but at least I am setup with a few options for EPROM programming now.


If you want to see what I program with these devices, the full range of Minstrel and Mini PET kits and accessories are available form my SellMyRetro store.

All the links can be found here:


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