I have an XTL 5000 with a VRS-750 that I cannot get to read or write. I keep getting “Radio Failed to Acknowledge”. I have tried 3 computers, 2 separate software revisions, tried to force the saved codeplug into it, used my cable on another radio, and It works so I know it isn’t the cable or the computer so it has to be the radio. I’ve tried unplugging the VRS and it causes the radio to stick open on TX as soon as it powers up and doesn’t read or write. I’m using the rear accessory connector with a OEM programming cable that ends with a DB9. I’m pretty lost on this one. Service manuals haven’t helped. I cloned this radio to another spare and have the same exact issues with it as well.