Fix for HD500 no sound from any Variax

Started by TechFixer, October 20, 2023, 04:06:38 PM

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I've had 2 Variax's for years  (300 and a 500).
Recently I picked up a used HD500 which worked fine using guitar input but no sound from the VDI (Variax input). I tried 2 official Line 6 VDI cables and no sound. If I connected the VDI AND plugged in a 1/4" cable from the Variax to my amp I got sound (The HD500 was supplying power to the Variax) I visually checked both guitar and HD500 VDI jacks and no bent pins.

Next I opened the HD500 up and after looking at a schematic I found online (not particularly accurate as there were no "processing schematics" but there was  one for the VDI connection. What I found was an open inductor (L42).When you check many inductors with a multimeter they usually show up as a short or very low ohms. There are 2 lines that bring the signal from the Variax to the HD500 and that one was open (probably someone plugged in an ethernet cable a network jack or something) I don't have any of these inductors but bridged across the surface mount chip with wire. Yes I know the inductor also may act as circuit protection (mostly RF interference and had a low current rating) and I'll find a suitable "official" replacement when I can.


Hi, I'm TechFixer.... I'm a gear-A-Holic and I have a problem. (Hi TechFixer!!) Pretty much every Roland guitar synth from the GR-50 to the VG-99. Roland VGA amps too. Lefty Line 6 500 Variax (converted to strung righty) FrankenPeavey ATG and Fishman TP