Complete Diagnostic & Repair of a Dead Accuphase P-300 Power Amplifier

Описание: This Accuphase P-300 power amplifier arrived completely dead, presenting with multiple major failures including a blown channel, a damaged soft start circuit, faulty protection and power supply boards, and leaking main filter capacitors. Bringing it back to proper operating condition required systematic diagnostics and component-level repair across several critical sections of the amplifier.

This restoration pushed my troubleshooting process further than usual, including the use of circuit simulation to identify and correct a factory error in the power supply construction. Follow along as I diagnose and repair this classic Accuphase amplifier step by step.

Learn audio repair by watching me work:
  / novaluxstereophonic  

Chapters
00:00 Introduction
01:35 First Look & Soft Start Diagnosis
07:10 Testing the Power Transformer & Power Supply
11:43 Repairing the Power Supply Board
14:12 Testing the Working Channel
16:42 Repairing the Soft Start Circuit
21:41 First Power-On After Soft Start Resistor Replacement
23:36 Power Supply Service
30:00 Protection Circuit Analysis
32:46 Factory Defect Found Using EveryCircuit – 16V Supply Restored
36:57 Patreon Invitation
37:19 Rebuilding the Blown Amplifier Channel
50:46 Restoring the Lamp Flasher Function
51:29 Calibrating the Power-On Fault Detection Circuit
54:23 Baseline Distortion & Frequency Response Analysis
01:00:09 Bad Chassis Ground Causing THD & Frequency Response Issues
01:05:57 New Transistors Improve Distortion Results
01:10:53 Rebuilding the Blown Channel Again – Backwards Protection Diodes
01:15:15 Oscillation with Tektronix SG505
01:19:12 Main Filter Capacitor Replacement
01:25:00 Final DC Offset & Bias Adjustments
01:27:47 Meter Calibration
01:30:39 LED Conversion & Color Experimentation

Accuphase P-300 restoration, Accuphase P-300 repair, Accuphase power amplifier repair, dead power amplifier repair, blown channel amplifier repair, vintage audio restoration, hi-fi amplifier restoration, electronic amplifier rebuild, power supply repair, protection circuit repair, soft start circuit repair, amplifier troubleshooting, bench electronics repair, component level amplifier repair, vintage hi-fi repair, audio amplifier diagnostics, transistor amplifier restoration, Accuphase amplifier service, main filter capacitor replacement, DC offset and bias adjustment

YTL093