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Electronics voltage stabilizer

Circuit diagram to controle ac voltage form 90v to 280v

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Searching for the Electronic circuit diagram of AW870 wireless speakers

They have been discontinued, Audiovox used to market them. Last manufacturer was Recotron.

Jan 22, 2016 | Speakers & Subwoofers

1 Answer

Jamo e3 sub cuts off when i turn the bass control on the back of the box up

Hi. That could be a voltage overload issue. Some, if not all, active speakers/subs have overload protection circuitry so the unit doesn't burn up. If you have a voltage meter, check your outlet to make sure the voltage coming through falls within an acceptable range (i.e. 115-125 volts or 235-245 volts, depending where you are). If you don't have a meter, you should be able to get one for a few dollars either online or at a hardware or electronics store. Hope this helps

Feb 24, 2014 | Speakers & Subwoofers

1 Answer

The power supplies / ac adapters for my AW-871 speakers were both lost in a recent move. The speakers show input of 15v center + but no power spec. Do you have a suggestion for replacements? Thanks for...

Higher voltage then required is not so recommended, internal circuit may over voltage driven. some power amp max limit may fall within 18V only. See this link If your speaker power less then 30w you can choose 15V 2A will do or else select higher spec.

Jul 23, 2011 | Acoustic Research 900MHz Wireless Stereo...

1 Answer

I have Jamo E8sub need to be fixed. The power LED is not on, it was RED at one time (Did not turned Green), but not anymore. I checked the DC voltage on main IC (LM3886) no power on Pin # 1 and 5. Both...

the ic lm3886 should have voltage at its pin 1 and 5 , because it is the vdd supply pin of that ic. trace out, to where the track goes from pin 1and 5. it should go to the power supply or to any switching circuit. may be problem with its power supply side . any one of the voltage is missing. check the voltage regulators if there. check the power supply side i think complaint lies there. no need to replace the main board . from ur narration i think u have knowledge in electronics. make one more try to solve the problem.

Dec 30, 2010 | Jamo E8 SUB Subwoofer

1 Answer

My B&O Speakers are making a buzzing sound

You don't give us much to go on. What model? Self-powered?

What's "the aloy box"?

You have a ground loop or stray AC voltage circulating among your components. It could be dangerous to you and the equipment. Whatever you do DON"T touch anyhing grounded with your hand while touching what may be a 'hot' conductor.

Disconnect external cabling from the speakers and see if that changes anything. Then follow where it leads.

Maybe the source is in your unnamed electronics.

Try reversing the power cord(s). Maybe get one of those AC circuit phase checkers (available cheap at Dollar Stores) to see if your house wiring conforms to standards.

Apr 11, 2010 | Speakers & Subwoofers

1 Answer

Mordaunt Short MS409W cuts out. I think due to oversensitive overtemperature sensor on the heat sink. Some of the components (two electrolitic caps and a choke) close by look to have become very hot. With...

I read about lots of similar 'cutting out' problems on other bulletin boards, revealing that this is a common problem with this particular model. Many people had the faulty speaker replaced or repaired, then had a similar problem with the new one. As the manufacturer doesn't seem to have taken any responsibility for it and as I am an Electroinic Repair Engineer, I decided that I needed to find a creative solution.

I read lots of reports about fuses blowing as the wrong rating had been fitted by the manufacturer and reports of people fitting uprated fuses (very dangerous) after the higher rated fuses had blown. People often still had the same cutting out problems after doing this. I then found a 'fix' carried out by someone who clearly had a very rudimentry grasp of electronics but nevertheless claimed to have found a cure for this problem. I decided to check out this 'fix' which consisted of adding a link between two points on the power supply circuit board. This is the circuit board covered in black heat shrink sleeve.

I examined it and found that it contained a relay that transfers the secondary voltage from the turoidal transformer to the larger, circuit board. The relay appears to be responsible for switching through the primary positive power supply voltage for everything. So, by shorting out the input to the output, the electronics is no longer dependant on the relay operating to keep the supply going to the main circuit board. I figured that it could be the relay causing the 'cutting out' problems which is why the writers 'fix' worked.

I carried out this modification to the speaker I was repairing and as far as I can see it now works perfectly. The 'fix' does of course mean that the power is never removed from the main circuit board even if it is supposed to be, say for a 'soft start' or similar. Of course, since the speaker was basically scrap as it would have been to expensive to obtain and replace the faulty parts, this repair means that my customer now has his speaker back for very little cost.

If you at FixYa would like the full details for this repair, I will only charge you a one off fee of £80 for the several hours I have spent working on this solution. Of course I am perfectly happy to make the information available free to any member of the public or non-profit organisation that would like it. After all I only really checked out the repair that someone else had posted to make sure that it was reasonably safe and that it worked. No guarantees.


Jan 29, 2010 | Speakers & Subwoofers

2 Answers

I lost my GE Ultrasonic 2.1 Speaker power adapter and i need need ones but i dont know what to buy, the voltage it requires..6 or 9 volts?

at most electrical stores you can buy a universal power adaptors with a selection of socents to fit most connections. and which has a selector on it for various voltages settings.
take one of the little connectors and see which one fits. then checking the polarity on your device set the polarity the same when plugging the connector into the power supply cable. adjust voltage as needed.

Warning: when connecting a variable power adaptor alway connect on the lowest voltage setting and work up as too high voltage can distroy your appliance.

Nov 13, 2009 | GE Ultrasonic 2.1 Speaker

1 Answer

RCA WSP150Where can i have them serviced

Most of this newer stuff is disposable. Chances are, most of the sound circuits are on a single processor chip with a cryptic house number instead of the actual part number. A shop would charge more than the cost of a new system, and you probably couldn't get the parts to repair them yourself. If you're really attached to the system, your best bet is to replace the entire amplifier section with a new generic module, and rewire as needed. Parts Express and MCM Electronics probably have suitable amp modules.

Nov 05, 2008 | RCA WSP150 Main / Stereo Speaker

1 Answer

Center speaker Paradigm CC-70

may be voltage problem..try using stabilizer

Oct 31, 2008 | Paradigm CC-70 Speaker

2 Answers

Subwoofer probelm

I suspect you have a bad cable, a poor ground or a bad
power supply inside the speaker amplifier. The amplifier
(inside the sub-woofer) could also be defective.
1) Bad cable or connector:
If the (braided shield/outer tube) of the coaxial input cable is
not grounded, the cable will pickup line frequency "hum"
from surrounding power lines, house wires, lights and

This hum is then amplified by the speaker's amplifier
causing the constant bass sound you speak of.

Because the hum frequency fundamental is 60 Hertz in
North America, 50 Hertz in Europe, you hear it coming
mostly out of the sub-woofer, because the midrange and
high speaker circuits filter it out.

Check the input connectors, cable at both ends, wiggle
the jacks at a low volume setting to see if it changes.

Make sure that you are indeed using a properly shielded
coaxial cable.

A coaxial cable consists of a thin inner conductor, surrounded
by a flexible tube made up of a braided metal shield, which
must be grounded. This prevents hum from being picked up
by the sensitive amplifier inputs.

2) If the power supply within the sub-woofer's internal amplifier
is defective, the the power supply hum will also get coupled
into the amplifier and speaker with same results as above.

Power supply hum is typically twice the line frequency,
i.e. 120 Hertz, but not always, depending on what
component failed: Rectifier diode, filter capacitor, or
the voltage regulator.

3) Ground loops:
When you run very long cables between the source and
destination of an audio signal, multiple ground paths (must)
exist between the two points in space, creating complete
loop circuits.

Power line hum from the environment can (will) induce
heavy AC currents around these loops, creating a voltage
gradient across these cables, and in-between the end

Once again, this AC hum is coupled into the amplifier inputs.

Ground loops become a problem with cables over 10
feet long, and an astronomical problem for stage audio
engineers. To avoid ground loops, they must break
the circuit's continuity by using isolation transformers,
optical isolators, and/or differential input amplifiers.

So how long are your cables?

Most house stereo components are only designed to
handle 6 to 10 feet of cabling max.

30 feet is already asking for major trouble.

4) Feed back oscillation: This occurs when the output of
an amplifier is fed back to the inputs with a round trip
gain greater or equal to unity. The tiniest little electrical
disturbance is then amplified and re-amplified, over and
over again, usually at one preferred frequency, causing
the typical (ear-splitting) microphone squeal or howl.

In your situation feedback and/ loss of original signal
could be the result of mis-wiring the input cables.

Note that this is NOT as silly nor as unlikely as it sounds,
because many computer audio cards and even some
home stereo systems have re-configurable inputs and

SOFTWARE configuration decides which jack at the
back does what !!!!

On my computer, for example, the Realtek audio driver
tries to automatically figure out what cable is connected
to each jack (usually it gets it wrong)

Using the Realtek control panel applet, I can then
manually re-configure the gray jack as input,
the green jack as bass, pink jack as center.... etc.

If this situation also applies to your system, please check
the software configuration. Connecting an output cable to
an input jack will certainly cause a lot of HUM and not
much music.

5) Finally, don't rule out internal sub-woofer failure. Unlike
the passive stereo/hi-fi speakers of days gone by, modern
multi-channel theater systems with front, center, rear and
sub-woofer speakers are internally amplified, with active
frequency cross-over filters and special effect/ surround
sound capabilities.

Usually, the large sub-woofer contains most of the
electronics, amplifiers and filters.

It feeds the other speakers, and it is controlled by
an external volume control module which can be separate
or built into one of the tweeters.

These sub-woofer electronics are prone to poor design,
overheating and early failure. (Even fresh out of the box
like yours)

If you cannot get it working, take it back to the store,
and make the NICE salesmen **** with it.

Good luck
Please rate my answers

Jul 20, 2008 | Yamaha 5.1-Ch. Surround Sound Home Theater...

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