My new R5 cuts FFB / disconnects within minutes at rated torque. Pulled the Pit House logs and found the base resetting from undervoltage. Diagnosis inside.

      Bought an R5 + GS V2 from a Belgian retailer in June, only got to unbox it this    

      week. First session was unusable — either force feedback died completely or the    

      whole base dropped off USB, always within a few minutes of going on track.    

      Instead of guessing I dug into the Pit House device logs    

      (%LOCALAPPDATA%\MOZA Pit House\DeviceLog\). Turns out the base logs its own    

      failure before Windows even notices:    

      [ERRO] err_diag_svr.c:69    Under DC Voltage    

      [ERRO] diag_svr_event.c:86  error_code 129 occurs    

      [WARN] main_diag.c:145      system reset: bor_reset    

      That last line is the one that ended the debate for me — bor_reset is a    

      brown-out reset, meaning the MCU's own supply rail dropped below its reset    

      threshold. That's not a driver hiccup, that's the power collapsing.    

      8 of those in about 75 minutes. In one case the base logged the undervoltage at    

      19:16:27.438 and the USB device vanished ~1.5 seconds later. The base knows it's    

      dying before the PC does, which rules out USB/cable/driver.    

      After each event it logs error_code 159 (motor zero point lost) and 148    

      (parameter init checksum error) — that's why FFB goes limp instead of the base    

      fully rebooting on the milder ones.    

      **The test that actually nailed it:**    

      100% torque, under load : 8 failures in 75 min, first always within 1.5-4 min    

      50% torque, under load : 11 min of deliberately hard driving, ZERO failures    

      100% torque, idle       : 124 min powered, ZERO failures    

      Torque setting left at 100% the whole time on that last one. Nothing happens    

      until the motor actually draws current. So it's not a settings problem, not a    

      duty-cycle problem — it's purely current draw.    

      **Things I ruled out along the way:**    

      - Both wheels (GS V2 and the plain R5 rim) — identical failure on both    

      - Both USB controllers (CPU-attached USB 3.x and chipset USB 2.0) — no difference    

      - No hub, straight into a motherboard port    

      - Wall socket, no extension, no strip, no converter, no UPS    

      - Temps: 596 samples, max was controller 47C / MOSFET 50.3C / motor 50.8C, and    

      not a single over-temp error logged. A friend was convinced it was thermal    

      protection — the telemetry says otherwise, the protection tripping is the    

      undervoltage one.    

      - Not a game/settings thing either. Dropping in-game FFB strength made it look    

      fixed for a while (17 clean minutes instead of dying in 1.5-4), but then it    

      threw the same error_code 129 in **F1 25** — different title, different FFB    

      engine, separate settings. Lower strength just moves the threshold, it doesn't    

      fix anything.    

      - Took the base + its own adapter + its own cable to a **different building on a    

      different mains supply with a different PC** — fault reproduced there too.    

      So it's the unit, not my house and not my PC. My money is on the power adapter    

      not delivering rated peak current, with a faulty internal drive stage as the    

      other candidate.    

      **Questions for the hive mind:**    

1.       Anyone had an R5 (or R9/R12) throw error_code 129 / "Under DC Voltage", or    

         seen bor_reset in their logs? Did swapping the power brick fix it, or did the    

         whole base have to go back?    

2.       Is there any way to read the actual DC bus voltage as a number? Pit House only    

         seems to log a boolean undervoltage flag, no measured value.    

3.       Anyone dealt with Moza RMA from outside the EU on an EU purchase? Unit was    

         bought in Belgium, I'm in Turkey. Trying to work out whether they'll ship just    

         an adapter.    

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