19.07.2023
Switching power supply circuit diagram. We repair the pulse source, power supply, voltage converter ourselves, with our own hands
Repair of switching power supply. Anyone with basic radio-electronic skills can repair a power supply or voltage converter on their own. Take action, identify the problem and fix it. (10+)
We repair the switching power supply ourselves, with our own hands. Malfunctions
Attention! Some elements of the power source are under mains voltage during operation. Make sure you have the necessary qualifications to safely perform repairs on the switching power supply.
Diagnostics and repair of a switching power supply in most cases can be performed with basic skills in radio electronics.
Power supply device, step-down mains voltage converter
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IN modern world development and obsolescence of components personal computers happens very quickly. At the same time, one of the main components of a PC - the ATX form factor - is practically has not changed its design for the last 15 years.
Consequently, the power supply and ultra-modern gaming computer, and an old office PC work on the same principle and have common methods for diagnosing faults.
The material presented in this article can be applied to any personal computer power supply with a minimum of nuances.
Typical block diagram ATX power supply shown in the figure. Structurally, it is a classic pulse block on the TL494 PWM controller, triggered by the PS-ON (Power Switch On) signal with motherboard. The rest of the time, until the PS-ON pin is pulled to ground, only the Standby Supply with a voltage of +5 V at the output is active.
Let's take a closer look at the structure of the ATX power supply. Its first element is
:
Its task is to transform alternating current from the mains to constant power to power the PWM controller and standby power supply. Structurally, it consists of the following elements:
- Fuse F1 protects the wiring and the power supply itself from overload in the event of a power supply failure, leading to a sharp increase in current consumption and, as a consequence, to a critical increase in temperature that can lead to a fire.
- A protective thermistor is installed in the neutral circuit, which reduces the current surge when the power supply is connected to the network.
- Next, a noise filter is installed, consisting of several chokes ( L1, L2), capacitors ( C1, C2, C3, C4) and counter-wound choke Tr1. The need for such a filter is due to the significant level of interference that the pulse unit transmits to the power supply network - this interference is not only picked up by television and radio receivers, but in some cases can lead to the malfunction of sensitive equipment.
- Installed behind the filter diode bridge, which converts alternating current into pulsating direct current. Ripple is smoothed out by a capacitive-inductive filter.
Standby power supply is a low-power independent pulse converter based on transistor T11, which generates pulses through an isolation transformer and a half-wave rectifier on diode D24, powering the low-power integral stabilizer voltage on the 7805 chip. Although this circuit is, as they say, time-tested, its significant drawback is the high voltage drop across the 7805 stabilizer, which leads to overheating under heavy loads. For this reason, damage in the circuits powered from the standby source can lead to its failure and subsequent inability to turn on the computer.
basis pulse converter is PWM controller. This abbreviation has already been mentioned several times, but has not been deciphered. PWM is pulse width modulation, that is, a change in the duration of voltage pulses at their constant amplitude and frequency. The task of a PWM block based on specialized chip TL494 or its functional analogues – conversion of direct voltage into pulses of the appropriate frequency, which, after an isolation transformer, are smoothed by output filters. Voltage stabilization at the output of the pulse converter is carried out by adjusting the duration of the pulses generated by the PWM controller.
This page contains several dozen electrical circuit diagrams and useful links to resources related to the topic of equipment repair. Mainly computer. Remembering how much effort and time sometimes had to be spent searching for the necessary information, a reference book or a diagram, I have collected here almost everything that I used during repairs and that was available in electronic form. I hope this is of some use to someone.
Utilities and reference books.
Capacitor 1.0 - The program is designed to determine the capacitance of a capacitor by color marking (12 types of capacitors).
startcopy.ru - in my opinion, this is one of the best sites on the RuNet dedicated to the repair of printers, copiers, and multifunctional devices. You can find techniques and recommendations for fixing almost any problem with any printer.
Power supplies.
ATXPower.rar - Schematics of power supplies ATX 250 SG6105, IW-P300A2, and 2 circuits of unknown origin.
colors_it_330u_sg6105.gif - NUITEK (COLORS iT) 330U power supply circuit.
codegen_250.djvu - PSU diagram Codegen 250w mod. 200XA1 mod. 250XA1.
codegen_300x.gif - PSU diagram Codegen 300w mod. 300X.
deltadps200.gif - PSU diagram Delta Electronics Inc. model DPS-200-59 H REV:00.
deltadps260.ARJ - Power supply diagram Delta Electronics Inc. model DPS-260-2A.
DTK_PTP_2038.gif - DTK PTP-2038 200W power supply diagram.
FSP145-60SP.GIF - Power supply diagram FSP Group Inc. model FSP145-60SP.
green_tech_300.gif - Green Tech power supply diagram. model MAV-300W-P4.
HIPER_HPU-4K580.rar - HIPER HPU-4K580 power supply circuits
hpc-360-302.pdf - Power supply diagram SIRTEC INTERNATIONAL CO. LTD. HPC-360-302 DF REV:C0
hpc-420-302.pdf - Power supply diagram SIRTEC INTERNATIONAL CO. LTD. HPC-420-302 DF REV:C0
iwp300a2.gif - Power supply circuits INWIN IW-P300A2-0 R1.2.
IW-ISP300AX.gif - INWIN IW-P300A3-1 Powerman power supply circuits.
JNC_LC-B250ATX.gif - JNC Computer Co. LTD LC-B250ATX
JNC_SY-300ATX.pdf - JNC Computer Co. LTD. SY-300ATX power supply diagram
JNC_SY-300ATX.rar - presumably manufactured by JNC Computer Co. LTD. Power supply SY-300ATX. The diagram is hand-drawn, comments and recommendations for improvement.
KME_pm-230.GIF - Power supply circuits Key Mouse Electronics Co Ltd model PM-230W
Power_Master_LP-8_AP5E.gif - Power supply diagrams Power Master model LP-8 ver 2.03 230W (AP-5-E v1.1).
Power_Master_FA_5_2_v3-2.gif - Power supply circuit diagrams Power Master model FA-5-2 ver 3.2 250W.
MaxpowerPX-300W.GIF - Maxpower PX-300W power supply diagram
microlab350w.pdf - Microlab 350W power supply circuit
