Previously, I had TI-82 Stats.fr which is actually TI-83 Plus limited to basic TI-83 software, without flash support, etc...

The cable I made - parallel link, with cut-off original calc-to-calc cable - was working perfectly with it.

Then I got TI-83 Plus. The cable was too short, but calc was detected.
So I decided to extend cable. I didn't do anything except extending wires. I double checked all connections, diodes, resistors and everything was OK. But still, ever since I plugged that into calc and PC, there's nothing I can do to connect to calc via parallel link.
I tried reverting to original short cable, replaced diodes, replaced resistors, checked everything but nothing helps.

Interestingly, W32tran8x detects cable, and when I short the cable itself, it reports "Short circuit in cable or calc connected". But when I plug calc in, nothing happens and it doesn't show short circuit warning.
(Update) Of course I use TiLP to work with calc, but w32tran8x gives me this cable check feature.

So what's wrong? Is it possible that something inside calc is burned, and what?

P.S. I also ordered USB connectivity kit from eBay and I'm waiting for that to arrive.

What is w32tran8x? Use TiLP

Of course I use TiLP. I just use w32tran to check the cable. So do you have any idea what's the problem?

Yes, calculator works perfectly except that I can't connect to PC. As I said, when I short circuit cable, it reports short circuit but when calc is plugged it, it's not detected neither by TiLP or W32Tran8x...

If you had more than one calc, you could try connecting it to each other.