Hello All,
Got a Boston Acoustics PV800 Subwoofer needing some help. I really like this sub and would like to save it if possible. I know that it is a BASH amp and that I have very limited knowledge and skills. I probably know the names of about 25% of the components involved and I know a guy who can solder pretty well. I'll give a description of it's behavior and what I know and and have done so far. Hopefully someone here sees or reads something here for a fix.
Plugging the sub to power usually results is a dim (about 20% of expected brightness) LED indicator. This is regardless of the subs power switch setting (on, auto, off). If the switch is "off or auto" you get dim red, if the switch in "on", you get dim green. This sometimes give a faint, shrill squealing type sound from the sub. When powering on to a dim LED indicator you always get 160V from the power supply board (see circled areas in pics). . . the board that receives the 160V will then always output ~12V (see circled area in pics)
When the sub gets plugged in and works, of course the LED behaves as it should. The one other obvious difference is that the board that was outputting ~12V is now outputting ~30V
When the sub doing the dim LED behavior, I can jump start the sub as follows. For about 4 seconds, I run a hair dryer on the left half of the BASH labeled board then plug in the power cable. Sub immediately comes to life. If I now leave the properly working sub plugged in overnight and everything get warmed up, unplug the sub then plug it back in. . . I get the dim LED fail again.
There is only one repair that I have done (and it didn't change the behavior). In one of the circled areas in the pics, there were two transistors that had their faces blown off, I had them replaced.
Thoughts anyone?
Got a Boston Acoustics PV800 Subwoofer needing some help. I really like this sub and would like to save it if possible. I know that it is a BASH amp and that I have very limited knowledge and skills. I probably know the names of about 25% of the components involved and I know a guy who can solder pretty well. I'll give a description of it's behavior and what I know and and have done so far. Hopefully someone here sees or reads something here for a fix.
Plugging the sub to power usually results is a dim (about 20% of expected brightness) LED indicator. This is regardless of the subs power switch setting (on, auto, off). If the switch is "off or auto" you get dim red, if the switch in "on", you get dim green. This sometimes give a faint, shrill squealing type sound from the sub. When powering on to a dim LED indicator you always get 160V from the power supply board (see circled areas in pics). . . the board that receives the 160V will then always output ~12V (see circled area in pics)
When the sub gets plugged in and works, of course the LED behaves as it should. The one other obvious difference is that the board that was outputting ~12V is now outputting ~30V
When the sub doing the dim LED behavior, I can jump start the sub as follows. For about 4 seconds, I run a hair dryer on the left half of the BASH labeled board then plug in the power cable. Sub immediately comes to life. If I now leave the properly working sub plugged in overnight and everything get warmed up, unplug the sub then plug it back in. . . I get the dim LED fail again.
There is only one repair that I have done (and it didn't change the behavior). In one of the circled areas in the pics, there were two transistors that had their faces blown off, I had them replaced.
Thoughts anyone?
Solved! In the 5th picture (the pic of the board with "BASH" right in the middle). In this pic, there are two 50v 22uF capacitors. I had those two caps replaced and have had no problems in the last week. I hope this information can be of use to someone else.
Can you please let me know how you even got that board out of the enclosure. I am trying but I don't know if I want to get a chisel and pry this thing out or not. I was hoping it would just easily come out but it's not. How did you get yours out?
Avoid using the hair dryer trick anymore. It's a temporary fix and could put additional stress on the components.
Take pictures of the BASH amplifier board, particularly the area you circled where the transistors were replaced. This might be helpful for a professional repair technician.
Since you have limited experience with electronics repair, the safest option would be to consult a professional or look for a replacement amplifier board if possible. Otherwise, you might need to consider getting a new subwoofer.