Works on maximum volume level only and no left channel.
Protection relay replacement solved problem.
Pluses – good attention to phono input. MC and MM phono inputs available.Good for phonograph players .Support MM and MC phonograph cartridges. Massive heat sink inside , good and stable sound.
Minuses – chaotic board management design inside, sandwich boards installation in central area with overheating on bottom board.
Category: Blog
Repair case 4657687. 01/20/20223 Pioneer QX-9900 quad receiver
Case 4657687. 01/20/20223
Pioneer QX-9900 quad receiver.Distorted sound after 20 minutes.
Cleaning all front panel switches and control pots solved the problem.
Technical view feedback – nice unit , build to last long time , perfect modules separation for prive nting signal interference between modules, plus each section has own shield cover, multi-voltage transformer let you use this unit in any country around the world without modification , good quality components in use, good heat sink design, stable sound at any power level.
Minuses- hard to get to front panel switches and pots in case if they need replacement.
Case# 456230. MSC 3835 amplifier . Intermittent sound on / off.
After troubleshooting found bad protection relay .
Relay replacement solved the problem.
Technical Pluses – simplicity, easy to reach components.
Minuses – low grade protection relay TYPE MU2U unusual size they used in manufacturing process.