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Electronics design how to design unregulated power supply for output 9Volts with current 150mA? please give simple circuit diagram .

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  • Anonymous Mar 23, 2014

    no power, appears fuse has blown...do you know replacement fuse designation???

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Ac voltage - 1.414 times larger then dc required, through a full or half wave bridge (but not clean) then across a large cap electrolytic say 220uF then keep a load on it with a small tant and a .1uF mono. Will this be clean enough.

Posted on Dec 19, 2008

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Lenovo idea flexpad 20


1. Check for a bad battery. This is the most common problem for mobile devices like tablets, laptops and the like. Since the battery must be fully functional (at OEM specified outputs for volatage and current) for the device to operate (manuf. designed it that way to protect the circuits years ago), it is the most likley culprit. (FYI: I have two Lenovo laptops - one under the old IBM Thinkpad label and one newer Chinese Lenovo).
* Replace the battery with a new OEM replacement as I do not recommend after-market generics or refurbished)
2. Try a different power supply. Check the OUTPUT requirements on your existing power adapter (usually 5v) and locate a another adapter to see if it is the AC adapter. The only real issue you need to worry about is the OUTPUT voltage must match the original adapter to avoid damage. The current does not matter since the device determines how much current in mAH it requires so just concern yourself with the right OUTPUT VOLTAGE and the jack plug makes a proper fit. If a spare adapter is not available (Radio Shack sells a variable voltage adapter with a variety of interface plugs and they work very well for these issues) then try using the Lenovo adapter on another device. (I am assuming you do not have electronics tools or test bench and need to troubleshoot the old school way)
* Replace the dead adapter ensuring that the VOLTs are the same on OUTPUT as the original and the interface plugjack is the same size.

If, after doing the above two simple steps, consider that the MB (mainboard - motherboard) power supply is toast and the laptop is good for recycling only

Jan 19, 2014 | Lenovo IdeaPad Y530 Laptop

1 Answer

I need an owner's manuel for a Pioneer stereo power amp SPEC-4. I have a part # ARB-235. I think this amp is a product of the 1970's. Where would I be able to get my hands on the operating instructions?...


You can register with hifiengine.com andfind it and the service manual.

There really isn't a lot to a power amp to be operated. This one differs from most in that it has an input level control and VU meters.

From http://images.google.com/imgres?imgurl=http://www.incomesixdigits.com/spec4/spec4a.jpg&imgrefurl=http://www.incomesixdigits.com/spec4/&usg=__WbFLwPqHXjFHe_P2BCKyTT9CxQY=&h=652&w=1156&sz=526&hl=en&start=2&um=1&itbs=1&tbnid=5SVKh2leUGWXmM:&tbnh=85&tbnw=150&prev=/images%3Fq%3Dpioneer%2Bspec%2B4%26hl%3Den%26rlz%3D1R2ADFA_enUS360%26sa%3DX%26um%3D1


Dynamic 150 + 150 Watts Power Output, Generous High-power Design
The Spec-4 employs DC construction which excludes capacitors from the NFB circuits and uses a dual transistor differential amplifier with a current mirror circuit in the 1st stage. This provides a stable operation and also high gain over a wide frequency range. The pre-driver stage is a class A amplifier circuit with a regulated current circuit for the load. This makes for high-gain amplification with superior linearity. Furthermore, there is an overdrive limiter and power limiter circuit which is designed to protect the power transistors and make for added reliability.
The power stage employs a 3-stage Darlington pure complementary parallel SEPP circuit.
The SPEC-4 delivers Continuous Power Output of 150 watts per channel, min. RMS, at 8 ohms from 20 Hertz to 20,000 Hertz with no more than 0.01% total harmonic distortion.

Completely Independent and Perfectly Stable Left / Right Power Supplies
The mighty power supplies are completely separated for the left and right channels. Also, each channel is provided with two 22,000uF large-capacity electrolytic capacitors and large transistors with a superior regulation. They achieve outstanding channel separation and a clear, powerful reproduced sound, in addition to the wide frequency response. There is a built-in surge killer circuit to suppress inrush currents from the power transformers and high currents which charge the electrolytic capacitors. This circuit ensures that none of the parts are affected by these adverse currents.
Protective Circuits Composed of Fast-response Relays and Electronic Circuits
Each channel is protected by a DC and over current detection relay circuit. In the event of the speaker terminal shorting due to poor connections or when DC current is generated in the output, the output circuit is immediately disengaged and the speakers and transistors are safeguarded against any possible damage. The protective circuits also function as muting circuits when the power switch is turned on and off.
Peak Level Meters with Outstanding Waveform Response
This power amplifier incorporates logarithmic compression peak meters with a wide scale (-40 -+3dB). With 8-ohm speakers, they allow the output to be read out from 0.01W to 300W. Moreover, the meters feature a fast response for peak signal indication. In addition to the peak output reading, it is easy to interpret the dynamic margin with respect to the SPEC-4’s clipping level.
Input Level Controls with dB Calibration
The SPEC-4 is equipped with input level controls with direct readout attenuation values (-dB). These can be used to continuously adjust the input levels for each channel in accordance with the rated output voltage of the preamplifier. In this way, the SPEC-4 can perform the proper gain control according to the preamplifier’s output level. The preamplifier will thus be used in the condition possible for the best S-N ratio and distortion characteristics.
Stylishly Professional Front Panel Design
Just as you would expect from a sophisticated system, the SPEC-4’s front panel is professionally designed with the large level meters in the center. Also. The front panel’s dimensions allow the model to be mounted in an EIA standard rack, just like real professional-use amplifiers.
SPECIFICATIONS
ICs………………………………........................................2
Transistors………………………………...........................61
Diodes……………………………….................................62
Power Amplifier
Circuitry………………………………Current mirror loaded differential Amplifier
3 stage darlington parallel push-pull
Direct-coupled OCL. (DC amplifier construction)
Continuous Power Output of 150 watts * per channel, min. RMS, at 8 ohms from 20 Hertz to 20,000 Hertz with no more than 0.01% total harmonic distortion, or 180 watts per channel at 4 ohms from 20 Hertz to 20,000 Hertz with no more than 0.03% total harmonic distortion.
Total Harmonic Distortion (20 Hertz to 20,000 Hertz, 8 ohms)
Continuous rated power output………………………………................................0.01%
75 watts per channel power output……………………………….......................... 0.01%
1 watt per channel power output……………………………….............................0.01%
Intermodulation Distortion (50 Hertz to 7,000 Hertz = 4:1, 8 ohms)
Continuous rated power output………………………………................................0.01%
75 watts per channel power output……………………………….........................0.005%
1 watt per channel power output………………………………........................... 0.005%
Frequency Response………………………………...............5 Hertz to 100 kHertz +0/1 dB
Input (Sensitivity / impedance)……………………………............................1V/50k ohms
Output
Speaker……………………………….................................................4 ohms to 16 ohms
Damping Factor (20 Hertz to 20,000 Hertz, 8 ohms……………………………….........100
Hum and Noise (IHF, short circuited, A network………………………………........11 5dB
Miscellaneous
Power Requirements………………………………...................................AC 120V 60 Hertz
Power Consumption………………………………..........................................760 watts (UL)
Dimensions………………………………..............................480(W) x 187(H) x 445 (D)mm
18-7/8 x 7-3/8 x 17-7/16 in.

Feb 10, 2010 | Audio Players & Recorders

2 Answers

Circuit diagram


I'm afraid I cannot comply with your wishes, as there are copyright laws governing this, for one. (For existing circuitry)

Two, there is the liability issue. Take for example that I design the requested circuit, give it to you freely, and you or someone in your group is injured using my circuit.

Will state that this is a basic circuit design. I believe that if you 5 put your minds together, you can build this circuit.

Sep 14, 2009 | Powerline 200Watt DC to AC inverter...

1 Answer

Sony xplod 1200 watt amp quit no kind of protect lite on please


short answer yes... Long answer... Amp Failure: There are many different ways that an amp can fail but the two most common failures are shorted output transistors and blown power supply transistors (< those are not blown). There are several types of protection circuits in amplifiers. The most common are over-current and thermal. The over-current protection is supposed to protect the output transistors. Sometimes it doesn't work well enough to prevent the failure of the output transistors but it will work well enough to shut the supply down before the power supply FETs are destroyed. If the amp remains in protect mode, goes into protect mode or blows the fuse as soon as the remote voltage is applied, shorted output transistors are almost certainly the cause. If the fuse protecting the amp is too large, if the protection circuit doesn't respond quickly enough or if the power supply is poorly designed, the power supply transistors may fail. If you see a lot of black soot on the power supply transistors (near the power transformer), the power supply transistors have failed. Soot on the board doesn't necessarily mean the transistors have failed. Sometimes, technicians don't clean up the mess from a previous failure. Transistor Failure/Checking Transistors: In general, when a transistor fails, it will either short (common for output AND power supply transistors) or open (common for power supply transistors). Transistors act like valves. They control the current flowing through a circuit. A shorted transistor acts like a valve that's stuck open (passing too much current). In the case of an output transistor, the shorted transistors tries to deliver the full rail voltage to the speaker output terminal. If you've ever seen a damaged amp that pushed or pulled the speaker cone to its limits when the amp powered up (common on some Rockford amplifiers), that was almost certainly due to a shorted output transistor. When checking transistors, you most commonly look for shorted connections inside the transistor. You do this by using a multimeter to look for low resistance connections between the transistor's terminals. Note: I used the terms short and open on the previous paragraph. A short (short circuit) is a path through which current flows that should not be there. An open (open circuit) is a break in the circuit. It is most likely the power supply that has taken a ****.

Jan 01, 2009 | Sony Xplod XM-1652Z Car Audio Amplifier

1 Answer

No sound coming from speakers Blaupunkt GTA470 Amp


Amp Failure:
There are many different ways that an amp can fail but the two most common failures are shorted output transistors and blown power supply transistors (< those are not blown). There are several types of protection circuits in amplifiers. The most common are over-current and thermal. The over-current protection is supposed to protect the output transistors. Sometimes it doesn't work well enough to prevent the failure of the output transistors but it will work well enough to shut the supply down before the power supply FETs are destroyed. If the amp remains in protect mode, goes into protect mode or blows the fuse as soon as the remote voltage is applied, shorted output transistors are almost certainly the cause. If the fuse protecting the amp is too large, if the protection circuit doesn't respond quickly enough or if the power supply is poorly designed, the power supply transistors may fail. If you see a lot of black soot on the power supply transistors (near the power transformer), the power supply transistors have failed. Soot on the board doesn't necessarily mean the transistors have failed. Sometimes, technicians don't clean up the mess from a previous failure. Transistor Failure/Checking Transistors:
In general, when a transistor fails, it will either short (common for output AND power supply transistors) or open (common for power supply transistors). Transistors act like valves. They control the current flowing through a circuit. A shorted transistor acts like a valve that's stuck open (passing too much current). In the case of an output transistor, the shorted transistors tries to deliver the full rail voltage to the speaker output terminal. If you've ever seen a damaged amp that pushed or pulled the speaker cone to its limits when the amp powered up (common on some Rockford amplifiers), that was almost certainly due to a shorted output transistor. When checking transistors, you most commonly look for shorted connections inside the transistor. You do this by using a multimeter to look for low resistance connections between the transistor's terminals.

Dec 31, 2008 | Blaupunkt PCA460 Car Audio Amplifier

1 Answer

I have an audiobahn A8000t amp with the protection light on


There are many different ways that an amp can fail but the two most common failures are shorted output transistors and blown power supply transistors (< those are not blown). There are several types of protection circuits in amplifiers. The most common are over-current and thermal. The over-current protection is supposed to protect the output transistors. Sometimes it doesn't work well enough to prevent the failure of the output transistors but it will work well enough to shut the supply down before the power supply FETs are destroyed. If the amp remains in protect mode, goes into protect mode or blows the fuse as soon as the remote voltage is applied, shorted output transistors are almost certainly the cause. If the fuse protecting the amp is too large, if the protection circuit doesn't respond quickly enough or if the power supply is poorly designed, the power supply transistors may fail. If you see a lot of black soot on the power supply transistors (near the power transformer), the power supply transistors have failed. Soot on the board doesn't necessarily mean the transistors have failed. Sometimes, technicians don't clean up the mess from a previous failure.
In general, when a transistor fails, it will either short (common for output AND power supply transistors) or open (common for power supply transistors). Transistors act like valves. They control the current flowing through a circuit. A shorted transistor acts like a valve that's stuck open (passing too much current). In the case of an output transistor, the shorted transistors tries to deliver the full rail voltage to the speaker output terminal. If you've ever seen a damaged amp that pushed or pulled the speaker cone to its limits when the amp powered up (common on some Rockford amplifiers), that was almost certainly due to a shorted output transistor. When checking transistors, you most commonly look for shorted connections inside the transistor. You do this by using a multimeter to look for low resistance connections between the transistor's terminals.
Note:
I used the terms short and open on the previous paragraph. A short (short circuit) is a path through which current flows that should not be there. An open (open circuit) is a break in the circuit.

Dec 30, 2008 | AudioBahn A8000T Car Audio Amplifier

1 Answer

Well my amp comes on but it doesnt give out like bass power or its jus not working like it use to the light comes on orange or red


There are many different ways that an amp can fail but the two most common failures are shorted output transistors and blown power supply transistors (< those are not blown). There are several types of protection circuits in amplifiers. The most common are over-current and thermal. The over-current protection is supposed to protect the output transistors. Sometimes it doesn't work well enough to prevent the failure of the output transistors but it will work well enough to shut the supply down before the power supply FETs are destroyed. If the amp remains in protect mode, goes into protect mode or blows the fuse as soon as the remote voltage is applied, shorted output transistors are almost certainly the cause. If the fuse protecting the amp is too large, if the protection circuit doesn't respond quickly enough or if the power supply is poorly designed, the power supply transistors may fail. If you see a lot of black soot on the power supply transistors (near the power transformer), the power supply transistors have failed. Soot on the board doesn't necessarily mean the transistors have failed. Sometimes, technicians don't clean up the mess from a previous failure.
In general, when a transistor fails, it will either short (common for output AND power supply transistors) or open (common for power supply transistors). Transistors act like valves. They control the current flowing through a circuit. A shorted transistor acts like a valve that's stuck open (passing too much current). In the case of an output transistor, the shorted transistors tries to deliver the full rail voltage to the speaker output terminal. If you've ever seen a damaged amp that pushed or pulled the speaker cone to its limits when the amp powered up (common on some Rockford amplifiers), that was almost certainly due to a shorted output transistor. When checking transistors, you most commonly look for shorted connections inside the transistor. You do this by using a multimeter to look for low resistance connections between the transistor's terminals.
Note:
I used the terms short and open on the previous paragraph. A short (short circuit) is a path through which current flows that should not be there. An open (open circuit) is a break in the circuit.

Dec 30, 2008 | Visonik V4208 Car Audio Amplifier

2 Answers

Motorola DC power Supply (0-40volts, 0-40 amps cc) M/N R101AA, S/N 261CCl0469


There is a book, "Electronics for Inventors" (check Amazon), that will give you the basics of power supply design and electrical components including general scematics. Without more info on what the PS is supposed to produce in the way of voltage and current, there's not much more to be said.

Dec 22, 2006 | Motorola (6200510300010) Power Supply

2 Answers

No picture No sound


This is an indication that the sweep power supply did not give the turn on pulse from the SMPS, thats the main power supply. If you know how to use a multimeter I will send you the instructions to troubleshoot this supply. Or you may need to trouble shoot the sweep supply as well. If you have no electronic or solid state repair experience, Please stay safe and call in a trained tech to assist you with this repair. Good Luck PS please rate this thread

Oct 18, 2006 | Sony KV-27FS13 27" TV

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