Hi everyone, i’m hoping some one has the patience to point me in the right direction to repairing this fairly expensive boston acoustic msub
first the off/on/auto switch was busted so i forced it into auto mode by bridging a connection on the main board and now the blue light comes on but i don't get any audio output. Does anyone one have any experience repairing this amplifier or even a schematic? I believe this unit is very similar to the boston acoustic HPS10, HPS12 highout subs. There’s a few schematics of the HPS floating around but the preamp section is blurry and i can’t read alot
of it so maybe some one has a better quality one? I looked it over, checked some the mosfets, some of the power resistors and cleaned that nasty conductive epoxy glue stuff off but not having much luck in the trouble shooting department. The mosfets are heating up the heat sink to a normal temperature when i try to play a song so im leaning towards and issue with the preamp section
I did however find a part of the PCB that was discolored from heat that may be an area of interest. It consists of two transistors which you can see in the short videos i attached along with some pictures to my google drive.
As i was investigating the issue i notice some resistors and capacitors appear to be missing from the preamp board but it’s hard to tell if they broke off or if they were intentionally left off (see attached pic)
C263
R238
C259
R282
Boston MSUB board photos
first the off/on/auto switch was busted so i forced it into auto mode by bridging a connection on the main board and now the blue light comes on but i don't get any audio output. Does anyone one have any experience repairing this amplifier or even a schematic? I believe this unit is very similar to the boston acoustic HPS10, HPS12 highout subs. There’s a few schematics of the HPS floating around but the preamp section is blurry and i can’t read alot
of it so maybe some one has a better quality one? I looked it over, checked some the mosfets, some of the power resistors and cleaned that nasty conductive epoxy glue stuff off but not having much luck in the trouble shooting department. The mosfets are heating up the heat sink to a normal temperature when i try to play a song so im leaning towards and issue with the preamp section
I did however find a part of the PCB that was discolored from heat that may be an area of interest. It consists of two transistors which you can see in the short videos i attached along with some pictures to my google drive.
As i was investigating the issue i notice some resistors and capacitors appear to be missing from the preamp board but it’s hard to tell if they broke off or if they were intentionally left off (see attached pic)
C263
R238
C259
R282
Boston MSUB board photos
