please delete :/.
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Last edited by lifthanger; 01-18-2011, 04:39 AM. -
Re: Multisim troubles
Are you trying to design a common emitter amplifier? If so, you have your top base resistor wired to the wrong place. Edit: Just threw it in LTSpice - it does swing negative due to the input signal. There are two things wrong in your circuit.
#1. Your biasing is wrong.
#2. Your input signal is too high in amplitude. 7 volts AC peak is 14 volts p-p. The DC supply voltage needs to be at least this value minus the voltage drop of the transistor. Since you are not using a split supply, your DC supply is 12 volts. And since you're trying to get some gain as well... all you will get is a square wave with DC offset on the output.Last edited by Th3_uN1Qu3; 01-18-2011, 04:47 AM.A working TV? How boring!Originally posted by PeteS in CA
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Hi everyone,
Brought a non functionnal PS5. Apparently only a bad PSU...
No beep, nothing.
After some tests i found this :
- PSU is fine (12 volts stable)
- 12 volts line is shorted
- DA9065 was fried, F7003 also => Replaced both of them, short is gone on 12 volts line, no dead short anywhere else.
- By the way, nothing change. No signal, no power, no beep.
Mesuring all rails with my workbench psu (12 volts input)
- 0.00 amp drawing
- 12 volts, 5 volts, 2 volts, 1,15 volts are presents (suppose new DA9065 do is... -
Good day to all. The bite alarm drains 9-volt Krona batteries. Current consumption when switched on is about 50 mA. I wiped the board from oxides, I will attach a photo (on the board there is a j3y transistor and a 7533 stabilizer, the microcircuit is erased = (the 3.3-volt stabilizer heats up weakly. I replaced it, nothing changed. I unsoldered the microcircuit, the consumption disappeared. The resistance on the pins of the unsoldered microcircuit from the point clockwise is more than 2 megaohms, the 11th leg is presumably ground. I warmed up the microcircuit, the consumption does not change....
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Hello,
Dell Latitude 5420 P137G
Board: LA-K491P REV A01
I have received this laptop which was described as "does not power on or accept charge." Battery shows no sign of charging when charger is plugged in, nor does the board show any signs of life when battery is unplugged and charger is plugged in. No light from the LED at all or any other indications of activity.
Board seems to have no shorts, all power rails are fine and show high resistance.
When charger is plugged in, voltage is present in 3.3V rail but absent in others.... -
I have this 10 amp 0 to 30 volt switching power supply that decided to have a 630 milliamperes draw on it at 0 volts
I open it up to find non brands name capacitors in it
I am not sure how this switching power supply is set up
Could someone please explain how this power supply works
Here is the capacitor ESR results
(1) 47uf@50 volts 0.46
(2) 47uf@50 volts 0.45
New 47uf@50 volts 0.35
(1) 100uf@25 volts 0.34
(2) 100uf@25 volts 0.35
New 120uf@50 volts 0.08
(1) 220@25 volts 0.13... -
Hello everybody, I could use some help on this one... It's got me guessing...
I took pictures of all the boards and the pin out of the connector on the power supply that goes to the main board... I measured all the pins in relation to chassis ground, here are the result.
(B13v)1. 12.7 volts cycling (Vamp) 2. 12.7 volts cycling
(B13v)3. 12.7 volts cycling (PWM5) 4. 1.0 volts cycling
(OD_LE)5. 2.8 volts cycling (PWM4) 6. 0.9 volts cycling
(OD_ON)7. 2.8 volts cycling (PWM3) 8. 0.9 volts cycling
9. ground (PWM2) 10. 0.9 volts cycling...
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