Sorry just wanted to add that i tried the following test:
1. I started a Test Tone 80HZ on a YouTube video on my TV which feeds to an AV receiver
2. I measure the Subwoofer output channel on the AV receiver and that was showing around 80Hz freq and AC voltage of around 0.2V
3. I measure the output at the speakers terminals on the Subwoofer and i was getting around 86 to 90Hz Freq and AC voltage of around 0.3V to 0.4V
4. The gain button of the subwoofer works fine and the volume reduces to zero if i move it to zero and the volume increases it if i increase but the max AC...
jinu_j
Senior Member
Last Activity: 09-25-2024, 09:48 PM
Joined: 02-13-2016
Location: Mumbai
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How to test Subwoofer Amplifier with only a multimeter
Hi Folks
Need some advice on how to test a subwoofer amplifier if i have access to only a multimeter.
Problem
I have a Boston Acoustics active Subwoofer (soundware S). Its rated output is 200W. But the output i am getting is very low i can barely hear/feel it even if put the gain at max. I replaced all the capacitors in the Subwoofer amplifier but still no change.
Is there anyway to test this without getting an oscilloscope/Function generator to see if the fault is with amplifier, driver or the source??
Any advice would be appreciated... -
Generally should not make a difference....Leave a comment:
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My guess is 10U_0805_25V6K would stand for
Capacitance value - 10uF
Size of the SMD capacitor - 0805
Voltage Rating - 25V
Thermal Rating Code - 6 - This corresponds to 105 Degrees
Tolerance value Code - K - This corresponds to 10%...Leave a comment:
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You are right, there is no period of silence or cutoff. Another suggestion received was to replace all caps on the SMPS board as one or more of the caps could be causing a current limitation leading to low volume....Leave a comment:
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HI folks any advice would be appreciated. Just let me know if my theory of the lower power board (100W Power board being used instead of 200W Power board) causing the issue of low output from sub, holds water ??....Leave a comment:
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Reviving an old thread. I just could not solve the problem of low output on my Sub in spite of keeping gain at max i can barely feel/hear the sub. Just could not crack this problem.
Finally, i think i figured out what was wrong. My speaker set model is the Boston Acoustic Soundware S. The subwoofer included in this package is a 10-inch downward firing 200W RMS (Peak power of 300W) sub. Many years back this subwoofer had failed (power supply board had burnt out) and I had taken it to a authorized service center for repair. Sure, enough they did repair it and i thought it was fine....Leave a comment:
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Re: Boston Acoustics Soudware Subwoofer PowerSupply
Just measured voltages at CN3 and CN2. There is no material drop in voltage when heavy bass is played. The voltage hovers around 19.7 (CN3) and 31.8 (CN4)...Leave a comment:
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Re: Boston Acoustics Soudware Subwoofer PowerSupply
Can you advice on what and where to check. Are you referring to the voltage at CN3 and CN2 ?...Leave a comment:
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Re: Boston Acoustics Soudware Subwoofer PowerSupply
Yes and No. By doing the subwoofer has started working meaning i can feel the vibrations in the woofer and the vibrations increase and decrease as i lower and increase the volume button in the subwoofer, but the output even at max is very much lower that what it was originally. Earlier in songs with heavy bass i could feel the punch but now its barely there.
This is the second time the power board has blown, the first time i took it to a reputed service center and they repaired it. I assumed they...Leave a comment:
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Re: Boston Acoustics Soudware Subwoofer PowerSupply
Finally solved the mystery. It was dry solder on D2. Now getting 32V on CN2Leave a comment:
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Re: Boston Acoustics Soudware Subwoofer PowerSupply
So finally got the parts. i replaced the Zener ZD3 and C13. Voltage at CN2 is still 0. But i am getting +20V and -20V at CN3
Voltage across C3 is 315V
Voltage across ZD3 is 19V
Voltage at HO is 167V
Voltage at LO is 6V
Voltage at VS is 157V
Voltage at CN2 :
pin 1 = 0V
pin 2= -20V
pin 3 = Grnd
pin 4 = +20V
Any advice on how to trouble shoot this further. ThanksLeave a comment:
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Re: Boston Acoustics Soudware Subwoofer PowerSupply
Zd3 broke into half when i desoldered it. So guess thats damaged. The other components D1, R7,C13, C14 and R7 are fine.
Now await the replacement of ZD3 before i can continue testing.Leave a comment:
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Re: Boston Acoustics Soudware Subwoofer PowerSupply
Thats the surprising part, No other components is showing any burn marks. I think the zener got overheated and the glue around it burnt.Leave a comment:
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Boston Acoustics Soudware Subwoofer PowerSupply
Hi Folks
I am looking for help to trouble shoot my Boston Acoustics Soundware X subwoofer power PCB. The Circuit diagram is attached. I have checked the voltage across C3 (there is no capacitor as this is 240V board). The voltage i get is about 318V so i am assuming that the circuit behind that is working properly. But now I am not sure how to proceed. The circuit on the Left-hand side of the circuit is on a separate PCB that's soldered onto the board using the connector CN4 shown in the circuit diagram. So its difficult to trouble shoot components on that.
There... -
Re: Multimeter repair brymen 786
Check this video. he bypasses the knob completely to test and direct external switch. You can use it to confirm there is no issue with the knob and that power is fine.
[url]https://www.youtube.com/watch?v=UY9Myo5ngPQ[/url]
Check at time stamp 1:06:56 for the testRe: Multimeter repair brymen 786<br ...Myo5ngPQ[/url]Leave a comment:
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Re: Multimeter repair brymen 786
Hope you have eliminated the basic checks
- Fuse Check
- Issue with the knob ([url]https://www.youtube.com/watch?v=IoRks5bJw8Y[/url])
Are they all fine ?Re: Multimeter repair brymen 786<br ...hey all fine ?Re: Multimeter repair brymen 786
Hope you have eliminated the basic checks
- Fuse Check
- IssueLeave a comment:
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Re: Query on preventing reverse flow
Thanks folks for your responses. But does anyone have a solution for this?
One thing i can do is eliminate the -12V output.
But the other point is valid because for a fraction of a second when i switch between relays there is a possibility of 2 relays being live. The single output from the relays will go through a volt/Ammeter before going to the output banana plug. This will allow me to operate with a single volt/ammeter and output. Hence i dont want to use individual banana sockets for each output.
Any...Leave a comment:
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Re: Query on 24V supply
can i use this voltage/source on components that have specified range of 0-24V. For eg: if i am using an IC whose VCC pin range is 0-30V can i use this power source ?Leave a comment:
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Query on preventing reverse flow
Hi Folks
I need your help in a design problem. I have a power source that provide 3.3V, 5 V, +12V, and -12V. Each output is rated at 5A individually. Now i need to create a 4 way switch which will allow me to select the output I want. Unfortunately cannot find a 5 way rotary switch that can handle 5A. The ones i find are too big and used for main electricity board. Hence not suitable for my project.
So what i was thinking was to do the following
- Use normal 5 way rotary switch rated for 500mA.
- Connect the output of this to 4 channel 5V relay. So...
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