MUR860F Avalon 1346 Crypto Miner PSU3400 Power Supply Diode Repair

MUR860F Ultrafast Recovery Rectifier Diode | 600V / 8A TO-220F for Avalon 1346 PSU3400 Power Supply Repair

The MUR860F is an ultrafast recovery rectifier diode designed for the Avalon PSU3400 power supply. Packaged in TO-220F (direct plug-in through-hole) with FRED (Planar) wafer construction for ultrafast recovery time, low forward voltage drop, and minimal power loss — exactly the characteristics needed for the high-frequency secondary-side rectification stage of a modern 3400W ASIC PSU.

Headline specs: 600V voltage rating, 8.0A continuous current, FRED Planar construction, ultrafast recovery. Low forward voltage drop keeps conversion efficiency high; ultrafast recovery prevents reverse-current spikes that would cascade damage into the primary-side MOSFETs.

When to Replace the MUR860F

• Avalon PSU3400 no output — secondary-side rectifier diode open, no DC to the bulk capacitor.
• Excessive heat on the diode body — degraded junction increasing forward drop and dissipation.
• Visible damage on the TO-220F package — burnt, cracked, or discoloured after a fault event.
• Audible buzzing on the PSU — diode failing partially, causing irregular conduction at switching frequency.
• Secondary-side MOSFET also failed — voltage spike from a failing diode often takes the MOSFET in the same event.

MUR860F Specifications

FAQ — MUR860F Ultrafast Recovery Diode

Q: How do I confirm the diode is the failed part?
A: Power off, isolated from mains. Use DMM diode-test mode across the diode leads. Healthy MUR860F reads ~0.7-0.9V forward, OL reverse. Shorted reads 0Ω both directions. Open reads OL both directions. Isolate one lead to remove back-feed through surrounding components if results are ambiguous.

Q: Can I substitute a standard rectifier diode?
A: No — standard rectifiers have slow recovery times that don't match the PSU's high-frequency switching. A slow-recovery substitute will overheat and likely take adjacent components down with it. Stick with ultrafast recovery diodes for SMPS secondary-side rectification.

Q: Always check the secondary-side MOSFETs at the same time?
A: Strongly recommended. Voltage spikes from a failing diode often kill the adjacent MOSFETs. Inspect for discolouration and test continuity before returning the PSU to service.

Q: Bulk pricing for Avalon PSU3400 repair benches?
A: Yes — email contact@lys-sz.com for tape-and-reel quantities and matched MOSFET kits.

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Avalon PSU3400 repair benches stocking MUR860F diodes by the strip? Email contact@lys-sz.com for bulk pricing. Worldwide shipping from our Shenzhen warehouse.