Had background static on a KR-4200 I picked up. Followed HopJohn's advice and replaced Q1-4 (2SC1345) on the Main Amp board with Zetex ZTX694B. That cleared much of the background static issue, but static remains on the Left channel. Inspecting the board, I noticed chemical leakage from C24 (220uF/35V). Replaced that with a Nichicon 220uF/63V cap I had on hand. This did not effect the background static.
Measured DC offset on the L and R speaker outputs:
Channel: High, Ave, Low
L: 208.8, 45.5, -84.3mV
R: 1.3, 0.7, 0mV
Suggestions on what to look at to narrow down the problem? Not seeing any other transistors on that board that appear on the known bad transistor list.
Measured DC offset on the L and R speaker outputs:
Channel: High, Ave, Low
L: 208.8, 45.5, -84.3mV
R: 1.3, 0.7, 0mV
Suggestions on what to look at to narrow down the problem? Not seeing any other transistors on that board that appear on the known bad transistor list.