blekenbleu

This sounds to me like a MIDI connection problem, which are lines 3,6,7,8 on the Cat6, according to e.g. https://line6.com/supportarchive/thread/3362 That USB dongle communicates with Variax basically using MIDI protocol. Since Cat6 and dongle work elsewhere, continuity between those lines and that PCB are suspect.

That would be a Variax 700: no mag pickups, so pre-JTV 3+3 tuners, so not 300/600 no pick guard, so not 500 trem, so 700 http://www.guitarsolos.tv/partner-line-6-guitars.html?&L=1

Users of other Line 6 legacy products (e.g. Variax 300-700) encounter similar issues. 32-bit software and Java 6 are no longer supported by macOS. The workaround for me amounts to installing Sierra (NOT High Sierra) on another drive or partition and booting that for legacy Line 6 sessions, as described here: https://line6.com/support/topic/46770-pod-hd300-edit-on-osx-mojave/?do=findComment&comment=297626 I know not whether this will work for Macs released after Sierra..

I doubt that you will receive positive responses * Line 6 macOS software of that vintage was 32-bit and depended on Java 6, neither of which are supported by Mojave. Consider partitioning your boot drive and installing Sierra (NOT High Sierra). Sierra can still be obtained: https://www.macobserver.com/cool-stuff-found/macos-sierra-installer-download/ A macOS 10.12 installation requires about 16GB, and I would allocate at least 40GB.. I always run a Time Machine backup to a separate external drive before attempting these exercises, then unmount, power down, disconnect and put away that Time Machine drive before proceeding. 1) Use Disk Utility to create a second partition on the internal drive https://support.apple.com/kb/PH22240?locale=en_US To minimize confusion, give the new partition an unambiguous name and significantly different (smaller) size than the current macOS Mojave volume. FWIW, macOS Disk Utility `Erase` is what other operating systems call `format`.. While in Disk Utility, be sure to click the sidebar icon, and Show All Devices (instead of Only Volumes) to verify that the new partition is NOT in an APFS Container. MacOS 10.12 Sierra cannot be installed on APFS, but its installer will not report failure (unknown internal error) until AFTER wasting a half hour or more installing 94-96%. Click on the container for the new partition, select Erase and confirm that some "Mac OS Extended" option is checked. If not, then check one and Erase again. 2) Instructions for creating Bootable USB thumb drive for installing Sierra are here: https://computers.tutsplus.com/tutorials/how-to-create-a-bootable-usb-drive-for-macos-sierra--cms-28223 Plugin the "Install macOS Sierra" USB flash drive Be sure it mounts correctly 3) Reboot, pressing [Option] key select the "Install Sierra" USB drive 4) To avoid wasting time on a doomed installation, first select the Disk Utility option and erase again. If erase fails, then installation was doomed; - reboot to the current OS and go back to step 1) else quit disk utility and select install 5) Installation takes absurdly longer than advertised and has failed twice for me when a Mac slept before completion, so wiggle the mouse every few minutes to keep it awake.

I agree and hope that XPS includes >>some<< short-circuit protection, but had also (wrongly) originally supposed that simultaneous phone jack and VDI connections would be OK... Being naturally pessimistic, I speculate that some damage attributed to simultaneous VDI + phone cable connections may have been provoked by unfortunate XPS power sequencing, with or without batteries. Note this sequence of connections published in the Variax 600 manual: "Powering your Variax with the XPS Footswitch is easy. Use the included TRS cable (meaning “tipring-sleeve” or also simply known as a “stereo” cable) to connect the Variax to the INPUT jack of the XPS Footswitch. Connect the PX-2 power supply to the XPS Footswitch POWER jack, and use a standard mono guitar cable to connect the XPS Footswitch’s 1/4" OUTPUT to your amp or effects."

OK, that explains a lot of older Line 6 Community Support entries compromised by missing diagrams and images.. Meanwhile, diagrams of TRS phone plugs engaging jacks seem to be too risque for the non-dark Internet, much less with to-scale cross-section diagrams.. but here: Sadly, the sleeve in simplified diagram to right of the pictured jack is not to scale, since an actual jack sleeve's depth is over half the nominal 26 mm from jack entrance to tip contact point, while plug tip-to-sleeve distance is about 12 mm, pretty much guaranteeing: * plug tip-to-ring shorts whenever TRS plugs pass thru jack sleeves * plug ring in contact with jack sleeve when plug tip engages jack ring contact. The TRS jack pictured here lacks those jack ring (and tip?) switch[es] actuated by plug deflections which happen e.g. in Variax.. Combinations of undesirable (e.g. reverse-polarity power) interactions as those switch contacts activate (and bounce) during powered plug insertions and retractions lead me to suppose that worse can happen than I previously wrote, when plugging TRS with powered XPS.

When an XPS is powered, it supplies power on its TRS ring connection, relative to shield. Then, for a TRS cable already plugged into a Variax: * if/when the other end of that TRS cable gets plugged into the XPS, that plug tip first encounters XPS shield, then ring, sending power to the Variax audio out, returning thru the ring connection, which at that instant could be connected to XPS ground. * If/when a cable already plugged to a Les Paul or other guitar with passive pickups gets plugged to a powered XPS, the plug tip sends XPS power to the volume control when it encounters the XPS ring contact. - if that guitar volume control is full counter-clockwise, XPS power may get shorted. - if that volume control is full clockwise, XPS power may go to pickups. Else, for a TRS cable already plugged into a powered XPS * if/when the other end of that TRS cable gets plugged into a Variax, - its plug tip first encounters Variax shield, then an instant when tip and ring both contact Variax shield sending XPS power back thru cable tip to DI circuitry in the XPS. I don't know whether some impulse also feeds through to amplifier/Pod connect to XPS. - next, when that TRS plug tip initially contacts the ring in my Variax 300 connector, it measures continuity to shield, effectively shorting the XPS power supply. Diagrams might show this more clearly, but I do not know how to embed them here.

Using a TRS cable for connecting a Les Paul or any other guitar with passive pickups directly to an amp (or Pod or Helix) simply leaves the ring (R) connection unused. A Les Paul should not be damaged, since its jack only connects to tip and shield, but a powered XPS could be damaged if a Les Paul or other guitar jack shorts ring to shield (some do). Of course, the XPS could be removed or should at very least NOT powered when a non-Variax guitar is connected. Power to the XPS should ALWAYS be off when making or breaking connections to a Variax.

Since Windows 10 reports >>something<< connected, the USB cable is probably OK. Not recognizing the device typically means the driver is missing; download it from Windows HD500X driver Version 4.2.7.6 Released 8/21/15

Seemingly.. Starting from https://line6.com/software/index.html Set: Variax 300/600 | - All Software - | Mac OS X Click: [GO] Scroll down to and click [GET DOWNLOAD] for: Variax Workbench Version 1.75 Released 7/26/12

VDI is basically power + AES/EBU + MIDI: VDI interface diagram; It sounds like you only need wireless MIDI: Yamaha MD-BT01 Wireless AES/EBU has also been done, but connecting a battery-powered DAC to JTV DVI for wireless analog guitar sound may be more expedient.

While VAX700 was correct about DC polarity being critical, he was incorrect about HD500, which (2.5mm) center pin requires negative 9VDC..

This $17 power supply is advertised at Amazon for HD500 etc https://www.amazon.com/dp/B0154WFJDG

Neither the HD500 nor HD500X does MIDI over USB; you will need another box or dongle for that. Are you familiar with this: https://line6.com/support/topic/4588-hd500-midi/

If reports such as this are true: Apple abandoning Intel processors in Macs ... then we will all be keeping old software around; based on previous experience when Apple migrated from PowerPC processors: fat/universal binaries ... Apple will release a few versions of macOS that support both 64-bit Intel and ARM processors, but Intel-based Macs will be more negatively impacted. Apple's recent drop of support for 32-bit software can bee seen as an initial step in this evolution.