GPU REPAIR CONTROL UNIT — WIRING OVERVIEW
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INPUT
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12.5V DC via banana plugs (top of unit)
Supplied by bench PSU (linear or SMPS) — set current limit before powering on
Typical: 3A for most GPUs | 4.5A for RTX 5080 | up to 6A for RTX 5090

SIGNAL PATH — TWO BRANCHES FROM INPUT
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BRANCH 1: Variable Buck-Boost Converter (Independent)
  Input: 12.5V from bench PSU
  Module: DC-DC Buck-Boost, 5V-30V in, 0.6V-30V out, 4A
  Switch: Blue illuminated button (on/off)
  Output: Banana plugs on front panel (variable 0.6V-30V, 4A)
  Note: Fully independent from multimeter branch

BRANCH 2: PZEM-031 Multimeter Module
  Input: 12.5V from bench PSU (in parallel with branch 1)
  Output splits three ways via red illuminated switch:

  a) 12.5V passthrough → banana jack (direct passthrough from PZEM output)
  b) Step-down module 1 → 3.3V output banana jack (adjustable buck, set to 3.3V, 3A)
  c) Step-down module 2 → 1.8V output banana jack (adjustable buck, set to 1.8V, 3A)

COMMON GROUND
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All three outputs from the PZEM branch share a common negative/GND rail
GND banana jack on top of unit for multimeter probe connection

GPU CONNECTION
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Custom PCIe cable: banana plugs (12.5V + GND) → 6+2 pin PCIe connectors
PCIe riser card (VER018, PCI-E 1X to 16X) used to seat GPU on bench

SAFETY NOTE
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This unit does NOT provide safety protection — that is handled by your bench PSU.
Always set current limit on bench PSU BEFORE powering the unit.
Never exceed rated current for each output rail.
