Do you have a question about the Hitachi HA-3700 and is the answer not in the manual?
Procedure for removing the unit's outer casing and front escutcheon.
Steps for removing power transistors and main circuit boards.
Setting quiescent current for optimal transistor bias.
Ensuring zero DC offset at speaker outputs for stability.
Verifying the integrity of the super linear circuit components.
Important safety and handling guidelines for servicing the unit.
Detailed explanation of the super linear amplifier circuit operation.
How the LED output level indicators are driven.
Description of the low-noise equalizer circuit for MC/MM cartridges.
Verifying the Area of Safe Operation circuit's functionality.
Checking the relay operation for speaker protection.