I have a PV700 boston sub with very little output.
It does not make any difference if I feed it spk level or line level source.
I'm not experienced in this kind of amplifier so I am asking for a helping hand here,
I have taken some pictures in the hopes of identifying the different boards it is made up of.
1) a picture of the back of the plate amp.
2) picture of what I believe to be the input and crossover board.
3) power supply board I think.
4 Amplifier board
Now I know that #1 is correct for sure.
Anybody have any ideas?
It does not make any difference if I feed it spk level or line level source.
I'm not experienced in this kind of amplifier so I am asking for a helping hand here,
I have taken some pictures in the hopes of identifying the different boards it is made up of.
1) a picture of the back of the plate amp.
2) picture of what I believe to be the input and crossover board.
3) power supply board I think.
4 Amplifier board
Now I know that #1 is correct for sure.
Anybody have any ideas?
Attachments
You really need circuit diagrams to follow the signal through.
I suppose you could test the output mosfets for shorts.
Check the power supply for volts.
I would also check the speaker for low impedance the voice coil could be partially fried.
I suppose you could test the output mosfets for shorts.
Check the power supply for volts.
I would also check the speaker for low impedance the voice coil could be partially fried.
Speaker checks fine with my impedance meter.
If mosfets were shorted I wouldn't have any output would I? Also there isn't any excessive current draw.
Signal is good but just low in level.
I generally repair everything I work on without schematics. Generally by the time I get a schematic I have the item repaired. I find companies like this unwilling to share any information that is why I entertained the idea that one of the cult followers here might have access and be willing to share.
If mosfets were shorted I wouldn't have any output would I? Also there isn't any excessive current draw.
Signal is good but just low in level.
I generally repair everything I work on without schematics. Generally by the time I get a schematic I have the item repaired. I find companies like this unwilling to share any information that is why I entertained the idea that one of the cult followers here might have access and be willing to share.
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I see its an Indigo product (maker of Bash amps) Well.. Boston Acoustics will not under any circumstances release the service manual or schematic. 😱 I wanted a schematic for my Micro90pv plate amp (Also Indigo)
Indigo was bought by some Chinese company, and the website is now defunct.. So you might not have luck servicing the amp. Sorry.
Indigo was bought by some Chinese company, and the website is now defunct.. So you might not have luck servicing the amp. Sorry.
This type active subwoofer need Spk level at input to max sounding, have tou try to input from mono source? stereo input has + & - polarity & if wrong connection the sound will be small at the end.
or any possibility you can only test amp board + speakers without input & crossover board so you know which board is bad.
Hi,
3 and 4 are the other way round I would think.
The last time I came across this problem the sub was being fed
out of phase signals, due to some dodgy cable wiring, cancelling
the bass from both channels, giving weak poor output.
Its possible, I guess, the Bass-trac cicuitry is playing up .....
rgds, sreten.
3 and 4 are the other way round I would think.
The last time I came across this problem the sub was being fed
out of phase signals, due to some dodgy cable wiring, cancelling
the bass from both channels, giving weak poor output.
Its possible, I guess, the Bass-trac cicuitry is playing up .....
rgds, sreten.
I have 3 and 4 out of sink in the pictorial lineup.
I believe number 3 to be the power supply and 4 to be the power amp section. Picture 4 has the mosfet output stage on it.
The unit was only fed one signal as is only has one input for full range and one input for sub signal that is already processed thru a crossover.
To answer the question the signal feeding the amplifier was correct.
There should be no difference between feeding spk level into the unit and line level according to the manual.
I believe number 3 to be the power supply and 4 to be the power amp section. Picture 4 has the mosfet output stage on it.
The unit was only fed one signal as is only has one input for full range and one input for sub signal that is already processed thru a crossover.
To answer the question the signal feeding the amplifier was correct.
There should be no difference between feeding spk level into the unit and line level according to the manual.
Attachments
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diy didi I guess its you and me on this one.
Want to share voltages?
Its too nice of a little subwoofer just to junk.
Want to share voltages?
Its too nice of a little subwoofer just to junk.
OB, Yes sure looks like it!🙁
Mine has exactly the same symptoms. Will let you know if I fand anything.
By the way. You mentioned an impedance meter. Would like to see apicture of it.!
Mine has exactly the same symptoms. Will let you know if I fand anything.
By the way. You mentioned an impedance meter. Would like to see apicture of it.!
Ok! Its official.
This one's gonna be teeth pulling without a schematic. Burnt components on amplifier board.😡
This one's gonna be teeth pulling without a schematic. Burnt components on amplifier board.😡
Which impedance meter would you like to see? I have a TOA, Goldline, and I have a German one.
What voltages do you have from your power supply? I don't seem to have much +4-6 - 4-6. Cannot run a output stage with that voltage. The plus and minus 15 volts are there and steady.
What voltages do you have from your power supply? I don't seem to have much +4-6 - 4-6. Cannot run a output stage with that voltage. The plus and minus 15 volts are there and steady.
IIRC the trick with BASH amps is a special power supply which tracks the audio signal. I've seen a few dead BASH amps, and the power supply section is usually what's blown up.
As BASH is a proprietary design which is kept super secret and you have to be a licensee to get the details, it's unlikely you'll get schematics to repair it, and if the custom IC's have died (which is likely), its a write off.
You can buy plate amps featuring BASH technology fairly easily it seems. Perhaps this is the best solution for a repair - provided of course that the sub's voice coil is intact
As BASH is a proprietary design which is kept super secret and you have to be a licensee to get the details, it's unlikely you'll get schematics to repair it, and if the custom IC's have died (which is likely), its a write off.
You can buy plate amps featuring BASH technology fairly easily it seems. Perhaps this is the best solution for a repair - provided of course that the sub's voice coil is intact
OB!
Cool Meters!!! Mine doesn't even have output present on supply. Amp board has burnt resistors. Really need a schematic for this!!
Cool Meters!!! Mine doesn't even have output present on supply. Amp board has burnt resistors. Really need a schematic for this!!
I called Boston Acoustics yesterday, and called all of their service centers in the US.. only 3 service centers. I called regarding my micro90pv. They said that the schematics are on Boston's internal web thing they have access too. Last year they were removed. The no longer have service manuals, schematics or parts for it. I knew about the PV700 thread here, and asked about it.. It went down the same path as the Micro90pv.. So no chance of schematics or service manuals.
I'm hoping Original Burnedfingers gets around to me this week on a box and shipping costs. I'll see what I can do. I'm going to do my best and draw a schematic for the amp board.. At least on the burned components that you have. So what is burned? Or did the silkscreen get burned beyond read?
My Micro90pv amp had a MOSFET that went in smoke. It was my fault, and the story is long, but it went up in smoke. So no schematics, I decided to shotgun it and replace all semiconductors. Too bad I forgot what some of the transistors are.. So I'm out of luck.. but an ebay seller selling the same sub as I have might be able to help me out..
Also, the ICs on the amp.. or on my 90pv are standard OP amps. No custom ICs or anything.
With your amp diy didi, we need to figure out what went wrong. Did the power supply go haywire and cause the burned resistors on the amp board, or did something on the amp board kill the power supply? Can you post some pictures of your amp board?
I'm hoping Original Burnedfingers gets around to me this week on a box and shipping costs. I'll see what I can do. I'm going to do my best and draw a schematic for the amp board.. At least on the burned components that you have. So what is burned? Or did the silkscreen get burned beyond read?
My Micro90pv amp had a MOSFET that went in smoke. It was my fault, and the story is long, but it went up in smoke. So no schematics, I decided to shotgun it and replace all semiconductors. Too bad I forgot what some of the transistors are.. So I'm out of luck.. but an ebay seller selling the same sub as I have might be able to help me out..
Also, the ICs on the amp.. or on my 90pv are standard OP amps. No custom ICs or anything.
With your amp diy didi, we need to figure out what went wrong. Did the power supply go haywire and cause the burned resistors on the amp board, or did something on the amp board kill the power supply? Can you post some pictures of your amp board?
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