Hello everyone,
Got a Boston Acoustics HPS-10SE I'm trying to repair. Got it all pulled apart and immediately noticed the nasty glue over everything, so have spent time removing that. The NP caps on the Class-D board were toasted, so replaced those. Also replaced the couple power transistors with equivalents (TTA004B, and TTC004B) on the main board, and the two caps on the +-15V outputs (C05 and C06), but, continues to not work. Sadly it was doing the same thing before both of these "throw parts at it" options. With the class-D attached to the amp board, I can physically hear the NP caps resonating =( and they get quite hot. With the Class D uninstalled from the board, but the pre-amp board hooked up, the positive 15V rail power transistor (Q01) gets quite toasty and seems to go into thermal shutdown (the positive rail craps out). With the pre-amp board unattached, all the power rails seem good and solid. So either the preamp board has a fault, or it doesn't like the class-d being unattached.
The service manual, which includes the schematics for all but the stupid "proprietary" Class-D board is attached (it's freely available from the BA website if you login). I'm not sure how to troubleshoot this tbh since it wants to fight me doing it piecemeal. Maybe hook external +-15V to preamp board and see what it does?
Got a Boston Acoustics HPS-10SE I'm trying to repair. Got it all pulled apart and immediately noticed the nasty glue over everything, so have spent time removing that. The NP caps on the Class-D board were toasted, so replaced those. Also replaced the couple power transistors with equivalents (TTA004B, and TTC004B) on the main board, and the two caps on the +-15V outputs (C05 and C06), but, continues to not work. Sadly it was doing the same thing before both of these "throw parts at it" options. With the class-D attached to the amp board, I can physically hear the NP caps resonating =( and they get quite hot. With the Class D uninstalled from the board, but the pre-amp board hooked up, the positive 15V rail power transistor (Q01) gets quite toasty and seems to go into thermal shutdown (the positive rail craps out). With the pre-amp board unattached, all the power rails seem good and solid. So either the preamp board has a fault, or it doesn't like the class-d being unattached.
The service manual, which includes the schematics for all but the stupid "proprietary" Class-D board is attached (it's freely available from the BA website if you login). I'm not sure how to troubleshoot this tbh since it wants to fight me doing it piecemeal. Maybe hook external +-15V to preamp board and see what it does?