DIY repair Adlx65ndc3a

Lenovo power supply, model ADP-065KH B 20V 3.25A.
PWM DAP013F, key 2SK3569, pnp gate transistor; in the secondary DAS001. Plug for 2 pins.

The fuse burned out, PWM, resistors in the feedback and in the gate, a 0.2Ω resistor in the source, PNP transistor in the gate. The 120uFx420V capacitor was swollen and leaking.

Replaced everything burnt, washed, dried. Shim DAP013F not found. There was a DAP013D, and I installed it. For reliability, I replaced the key with FDPF10N60Z.

I turn on the lamp, the lamp does not light up. At the output of the PSU “0.0”, no voltage appears even for a short time.
BUT!
On the PWM power capacitor 9-13V jumps.
I tried to turn off the optocoupler - the output is unchanged.

Question:
1. Tell me about PWMs, does anyone have information on how DAP013F differs from DAP013D?
2. where to look for a malfunction?

When buying a laptop or netbook, more accurately calculating the budget for this acquisition, we do not take into account further related costs. The laptop itself costs, say, $500, but another bag is $20, a mouse is $10. When replacing a battery (and its warranty life is only a couple of years), it will cost $ 100, and the power supply will cost the same amount if it burns out.

It is about him that the conversation will go here. One not very wealthy friend, the power supply for an acer laptop has recently stopped working. You will have to pay almost a hundred dollars for a new one, so it would be quite logical to try to fix it yourself. The PSU itself is a traditional black plastic box with an electronic pulse converter inside, providing a voltage of 19V at a current of 3A. This is the standard for most laptops and the only difference between them is the power plug :). I immediately give here several power supply circuits - click to enlarge.

When you turn on the power supply to the network, nothing happens - the LED does not light up and the voltmeter shows zero at the output. Checking the power cord with an ohmmeter did not give anything. We disassemble the body. Although it’s easier said than done: there are no screws or screws, so we’ll break it! To do this, you need to put a knife on the connecting seam and hit it lightly with a hammer. Look, do not overdo it, otherwise you will cut the board!

After the case slightly diverges, we insert a flat screwdriver into the gap formed and forcefully draw along the contour of the connection of the halves of the case, gently breaking it along the seam.

Having disassembled the case, we check the board and parts for something black and charred.

The continuity of the input circuits of the 220V mains voltage immediately revealed a malfunction - this is a self-restoring fuse, which for some reason did not want to recover when overloaded :)

We replace it with a similar one, or with a simple fusible one with a current of 3 amperes and check the operation of the PSU. The green LED lit up, indicating the presence of a voltage of 19V, but there is still nothing on the connector. More precisely, sometimes something slips, like when a wire is bent.

You will also have to repair the cord connecting the power supply to the laptop. Most often, a break occurs at the point of its entry into the case or at the power connector.

We cut off at the body first - no luck. Now near the plug that is inserted into the laptop - again there is no contact!

A hard case is a break somewhere in the middle. The easiest option is to cut the cord in half and leave the working half, and throw out the non-working one. And so he did.

Solder the connectors back and test. Everything worked - the repair is completed.

It remains only to glue the halves of the case with “moment” glue and give the power supply to the customer. The entire repair of the PSU took no more than an hour.

Upon inspection, a burned-out K10A60D transistor was found to be changed to P10NK60ZFP and the melted resistors R5-0.18 ohm were replaced by 0.15 ohms.R36 3 Kom replaced with a new one. Capacitor 4.7 * 50v replaced with a new one.

A voltage of approximately 297 across the large capacitor is present.

But there was no output voltage. Tell me where to measure next and how to troubleshoot.

Tell me, is there a diagram for it?

drawing the hot part is easy
this table will help you find the right shim

if I understand correctly, then this is 22ARZV, but how can I check it?

well, at least they could have guessed to check it by the power outputs, drivers and OS.

Found this on the internet

Marking 22ARZV
Conclusions.
1. judging by the board, overvoltage protection, thermal protection ..
2. FB
3.CS
4.GND
5.DRV
6. VCC

I measure with a tester and put a black wire on the 4th leg, and on the rest it shows 58 volts everywhere.

Or should I just check it with an oscilloscope?

And tell me what to substitute there, that is, I can’t find where to buy this 22ARZV.

Under a microscope, small balls of tin appear as if they had come out of it. It's probably dead, what can I replace it with?

meh. but to draw a diagram and think a bit about how, where and with respect to what measurements to make means not to offer? attempts to find a ready-made punched card on the Internet are commendable, but still learn how to punch them for yourself.
draw, think, look through some docks with suitable wicks, such as some kind of NCP1250 that came to hand, think about what parameters are needed in the circuit and look for analogues in stores.

I explain the situation.
Previously, Belarusians took tons of them from me for restoration.
I bought lots from the officials.
Then they changed the profile and stopped taking.
Now there are remnants of those times - 500 pieces.
SLOWLY being sold for refurbishment or for cords at virtually the price of ORIGINAL cords.
If someone is interested, I can either throw off the rest or even resume the purchase of lots with faulty PSUs.

And so the idea arose to break up the power supply, leave the cords for sale, and sell the power supplies themselves for refining (if anyone does not know, for processing into copper, aluminum and precious metal).
Plastic is also bought for recycling, but it's cheap, so I just throw plastic away.
For there is no room for consolidation.

Then I listen to suggestions, if any.
Better in LAN and with phones (and call time for Moscow time - I have almost unlimited in the Russian Federation (only Crimea and something like Yakutia are not included there)

_________________
ACODIS
Supply of spare parts and components for laptop repair.
matrices
Keyboards
Cooling systems

Today I will talk about how to carefully open a glued (soldered) power supply from a laptop, monitor or printer. Such power supplies are often found and many have a lot of questions - how to open them without breaking them at all. Test subject for today - external glued power supply unit SAD04214A from Samsung 960BF monitor. By the way, the declared malfunction of this couple is spontaneous shutdown.

I will tell you more about how to disassemble the Samsung SyncMaster 960BF monitor later. So, we have a power supply unit, at the output of which there is 14 volts of direct voltage and a maximum current of 3 amperes.

The plug of this power supply is made classically - the internal output is “+14 V”, the external one is a common wire.

Here's what it looks like power supply seam monitor before disassembly.

Especially for readers, I took disassembly video. This video is suitable for any glued power supply for a laptop, monitor, printer or other equipment. The main principle is to insert a sharp tool into the seam of the power supply and confident blows split it into two halves.

This is how it should look the seam of the power supply after opening.

Taking out the board, I saw a characteristic darkening of the textolite, which indicates overheating elements on the board.

As a result poor-quality soldering at the factory - microcracks formed in the solder. Because of this, the resistance of the “resistor-track” contact increased and it began to heat up more intensively, from which the microcrack grew, because the mechanical strength of the solder, as you know, decreases with increasing temperature. First microcrack below the resistor.

The second microcrack in the solder.

The third crack was already revealed at resistor wobble, whose leg is soldered to the board tracks in this place.

On top of the resistors are filled with some kind of rubber foam. It is possible that it impairs heat transfer between the elements inside the power supply case.

Remove this glue and see overheated resistors. The paint was even charred on them at the place where the metal leads were attached to the body of the resistors.

Solder these resistors and change for similar ones. The resistor on the left has a value of 33 kOhm, and on the right 33 Ohm.

I determined it by resistor marking table with ring color marking.

Soldering resistors in place and do not spare solder and flux. Overheated areas of the board tracks do not hold solder well.

That's what happened from radio elements.

We check necessarily condition of electrolytic capacitors, who are afraid of overheating. Just look at how flat their top is to make sure everything is fine. But if you change, then only for capacitors Rubycon 1000uF 25V and capacitors Nippon 2200uF 25V. There are cheaper decent ones (but always 105 degrees) Samwha 2200uF 25V.

This completes the repair of the power supply. It remains to collect everything back into the case and check for stability. Now you can feel how carefully you disassembled the power supply housing. If both halves converge with a seam width of about 1 mm, then everything is fine, if more, then plastic burrs along the seam may interfere. They must be removed with a knife or side cutters.

As soon as we achieve a satisfying seam, we drip a few drops on the seam (I usually drip at 6-8 points) of glue like "Second" and press the body with something heavy for 5 minutes. Now everything is ready - the power supply unit SAD04214A from the Samsung 960BF monitor was repaired and sealed back after opening.

Happy repair!
Your Soldering Master.

Don't forget to check C107 with a meter. In 90% of cases, either dried up or leaked.

Thanks for the addition. I completely agree.

Indeed, there was a problem in it - short circuit.

You never measure the ESR of conduits, but in vain!

It would be something to measure, then I would measure. And so, I just call for a breakdown. But Underzen is right, ideally ESR should be measured.

Good afternoon. Interesting site, thanks for sharing your work...

Regarding the PSU in sealed cases (even "in plugs"). Once they taught me, so I decided to share it - your idea is correct, you need to open it along the seam with a preferably strong knife, not very hardened, so as not to break. The main highlight is to put the PSU in the freezer for an hour or two. Plastic frozen very well then cracks along the seam even strongly glued (due to heterogeneity). I sometimes even just tap the seam with a heavy hammer so as not to spoil the look. Naturally, the pause in the repair is delayed by the time of thawing and evaporation of moisture then, but then the sweat is less and the quality is better.

Second, people are right about ESR. A few years ago, life forced me to do the repair of near-computer equipment just as hard. 99% of power supplies are already pulsed, their diagnostics using ESR sometimes turns into just a routine, and not troubleshooting, hi! Here is a device that I have been using for a long time, I tried a bunch of everything and settled on this particular design. Run along the branch if you wish. In general, everything is written in the dock for 1.01.

Thank you for your advice))) I will improve my skills))) Live and learn!

Good evening, comrades. I need your help! I am a happy owner of a samsung syncmaster 960bf monitor! The monitor holder broke!

Epoxy "Second" to help you)))

Thanks! Do you think this will help?

Yes, if the plastic surface is degreased, sanded and reinforced with metal, the epoxy resin will hold well. Restored laptops.

Good morning, Pike Master! I can send you a photo of my breakdown to understand what happened to me! Please send me your email address!

Good afternoon.I need your help, I have a 960 monitor, when the power is turned on, the power button on the monitor starts flashing, I noticed until the PSU warms up or you heat it up, the monitor does not turn on. What to do?

You need to fix the power supply. Disassemble and check capacitors and soldering. If it does not help - write.

Good post. I used to be interested in radio electronics. 5 stars from me and good luck!

Thank you Ivan. And good luck with your blog :)

Vyacheslav, there are two options - either the electrolytic capacitors have dried up - replace them (start with a small 47 microfarads 50 V), or a microcrack has formed in the soldering - solder the board. The rest is incredible.

Hello!
Today I replaced 4 capacitors (there are, like, only 4 of them).
Effect - "0".
It still turns off.
I went to repair laptops on the radio market. There, the cunning people directly said that soldering the conders to one place. And they said they knew what went wrong there. But they flatly refused to tell me. They say: pay money and we will repair it ourselves, and leave the conduits to yourself.
Can you advise on which forum to consult?

Over time, the laptop battery loses its original capacity, which affects the battery life of the device. If your laptop functions from a full charge for about an hour or even stops turning on without a connected power adapter, do not rush to purchase a new battery, in some cases it is possible to restore the laptop battery yourself.

If the battery starts to discharge too quickly, the first thing to try is to calibrate it. The most reliable way is to use a special utility, which is called differently depending on the manufacturer. For example, for Lenovo laptops it is Energy Management, for Aser it is Aser Care Center. The point is that it is necessary to launch a mode through the utility, which will first completely discharge the battery, and then fully charge it. During calibration, do not disconnect the power adapter, cut off the power supply, or use a laptop. The process can take from 2 to 10 hours. In some cases, calibration helps to restore the former autonomy of the device.

If the calibration does not give the desired results, or, as described earlier, the laptop does not work on battery power until the power adapter is connected, it's time to start repairing the battery.

• mock knife;
• multimeter;
• a soldering iron with a power not exceeding 40 W;
• several car light bulbs with a power of 21 W;
• cyanoacrylate glue.

Since laptop batteries are made non-separable, you will have to use a breadboard knife or other sharp object to open its case. Locate the seam on the battery and carefully cut it. Do this carefully so as not to damage the internal components.

Before proceeding further, be sure to determine the type of your battery, as this will affect the recovery process. If the laptop is new, then most likely you have a lithium-ion (Li-ion) battery, and if the laptop is older than 3-4 years, then it is possible that you have a nickel-metal hydride (NiMH).

If the described method does not bring results, you will have to change all the batteries at once. Sanyo's 2100 mAh nickel-metal hydride batteries are perfect. When replacing, do not use a soldering iron to connect the batteries in a chain. Instead, make contact holders and solder connecting wires to them.

These batteries are dangerous, so be extremely careful when repairing. Before starting, be sure to make sure that the battery is completely discharged.

1. determine the nominal battery voltage by counting the number of batteries and multiplying the resulting value by 3.7;
2. solder the light bulbs to the extreme outputs of the series-connected elements;
3. check the voltage - if it corresponds to the nominal, then go to the fifth paragraph (note that if the laptop does not work on battery power, the controller most likely failed);
4. if the voltage is less than the nominal, it is necessary first of all to unsolder the controller, and then all the elements from each other and check the voltage of each separately, while all elements with a voltage significantly less than 3.7 V should be replaced with new ones;
5. using a light bulb, discharge all batteries to a value of 3.2 V;
6. then glue the battery case, insert it into the laptop and carry out the process of full charging.

Another problem with Lithium Ion and Lithium Polymer batteries when they have not been used for a long time is that the voltage drops below the threshold at which the safety controller kicks in. In this case, the battery is not charging, and the voltage at its contacts is zero. To solve the problem, it is necessary to connect the laptop power source to a serial chain of battery cells through a 5 W light bulb and charge the battery to a voltage of 3.4 V per cell.

The main advantage of a laptop over a desktop computer is the ability to take it with you [. ]

Attention! This article is for informational purposes only, do not attempt to [. ]

Many PC users sooner or later may encounter a situation where, when connecting [. ]

A well-functioning battery gives meaning to the existence of a laptop, because in the absence of a battery, the device [. ]

The router is used to connect several devices to the Internet, a computer, laptop and others, via wired or wireless technology and create a local network between these devices. At the same time, the router implements a barrier between the local network it created and the Internet. Basically, routers work using NAT - Network Address Translation. Sometimes providers provide routers with the connection, the router can be inside a DSL modem or cable, or purchased separately. But, like any electronic device, routers can fail and many malfunctions can be fixed at home on your own. Consider some common router malfunctions and methods for their elimination, d link router repair.

Most often, the following reasons lead to router malfunctions:

1. large voltage surges in the network,
2. router overheating,
3. router software failures (firmware failures),
4. high-frequency interference of electromagnetic radiation during a thunderstorm (in this case, the wan port most often burns out if the provider does not put lightning protection on its cable),
5. human factor.

If the router malfunctions, it can lose data packets, work on the Internet and local network is disrupted, firmware is lost, the router can turn off, flash all the indicators.

Solving a problem associated with the inability to enter the router settings at its network address 192.168.0.1

If, after typing the network address of the router in the address bar, the router settings page does not open, then to eliminate this malfunction, you should perform the following operations:

• First, check that you have set the network card settings to automatically obtain an IP address and DNS address (using a direct connection to the router).

• If the network card settings are correct, then you need to use the Run command (press the Win + R key combination), then type - cmd and press enter. Now at the command line you need to enter ipconfig.

In the displayed settings, you need to see what value is opposite the inscription - Main Gateway. This address is used to enter the router settings. If the value of this address does not match the standard value, then the router may have been configured for a specific network with its own requirements. In this case, you need to reset this value to the factory settings. Sometimes in this field there may be no address value at all, and you also need to reset the router. To reset the router, you need to press and hold the Reset button on the router for a while. Usually five or ten seconds is enough.The button hole is narrow enough that you can use a ballpoint pen, needle, or paperclip to press it.

If resetting your router doesn't help, unplugging your ISP cable from your router may help. Pull out the provider cable from the router connector and configure the router without the cable connected. After that, you can reconnect the cable to the router.

Also check the firmware version installed in the router. Check the manufacturer's website for the latest firmware and update it if necessary. You can also check your network card drivers on your computer and reinstall them if necessary.

To troubleshoot a problem with not saving the router settings or if it is impossible to restore the settings from a separate file, you can try to carry out these operations by opening another browser. This method can help with other router malfunctions.

There can be many reasons for such a malfunction, and all of them are approximately equally common. Consider the main possible reasons.

If the network of your router is not displayed on the laptop in the list of available networks, then you need to check that the wireless network module is enabled. You can do this by looking at the adapter settings in the Network and Sharing Center on your laptop. The wireless connection must be enabled. In the off state, it will be grayed out and you will need to turn on the wireless connection. If you cannot turn it on, then you need to check if your laptop has a Wi-Fi switch and turn it on.

If, despite the fact that the wireless connection remains on, but shows the status - No connection, then you should check whether the correct drivers are installed for the Wi-Fi adapter and, if necessary, install them. Drivers must be downloaded from the manufacturer's website. This avoids potential driver incompatibility issues.

In addition, you can try to go to the router menu and change the value for the settings there and change the b / g / n parameter to b / g. If this change helped, then the 802.11n standard is not supported. You can also see in the same settings how the wireless network channel is specified, and if it is there - Automatically, then select the channel from the list.

If you often experience disconnections during work, it is recommended to update the firmware of the router. In many cases, this procedure helps to solve the problem.

Sometimes, when working with some Internet providers, to access local resources (torrent trackers, game servers), you need to configure static routes in the router settings. Such settings can be searched on the forums of the provider that provides you with the Internet.

Surely, many have already encountered the fact that the weakest point of many routers is their power supplies. They often break due to large voltage drops in the mains and failure of individual elements as a result of long work.

Defective or low-quality elements, a scheme that is not designed for a certain margin, can also lead to breakdowns. There are some typical power supply failures. In this article, we will consider repairing the power supply for the D-Link router. Power supplies such as JTA0302D-E and the like are used for Asus and D-Link routers, designed for an output voltage of 5V and a maximum current of 2-3 A. The appearance of such power supplies can be seen in the figure below.

If we consider the circuit and design of similar power supplies, then this is a circuit of conventional switching single-cycle power supplies. In such circuits, a PWM controller is used to control the operation of a field-effect transistor, which is connected to its output. As a result, the voltage is lowered to the desired value and rectified, and it is supplied to the output. A schematic diagram of such a power supply can be seen in the figure below. In this scheme, depending on the model of the power supply, there may be some minor changes regarding the ratings of individual components. The power supply outputs 5 volts.This voltage should not drop significantly under load (when the router is on).

To repair the power supply, you may need to use a soldering iron, solder, a multimeter, a knife and electrical tape. To open the plastic case of the power supply, you need to cut the glued seam of the case. This operation can be done with a knife, but it is more convenient to use a small drill for these purposes.

If you look at the power supply circuit in Fig. 2, you can see that a 2 amp fuse, a choke, a thermistor and a rectifier bridge of four 1N4007 diodes are installed at the input. If there is a large power surge in the network, then all these elements can burn out. They can be easily checked with a multimeter by measuring their resistance. To smooth the rectified voltage at the output, a high-capacity capacitor - C1 (22 or 33 microfarads) is placed after the diode bridge. This capacitor should be 400 V, no less. If it is out of order, then this can be determined by its appearance, it swells up.

In addition, the positive voltage from the diode bridge is fed to the PWM chip, in this case the UC3843B. This microcircuit is used to control the opening and closing of the P4NK60Z field effect transistor. Often the power circuit of this microcircuit contains a malfunction. This circuit has an electrolytic capacitor C6 and a zener diode ZD1, which is rated for a voltage of 20 volts. This capacitor must be of a certain capacity so that during operation the supply voltage of the microcircuit is always within the permissible operating limits. Therefore, the recommended capacitance is 100uF. If the capacitor is dry, then the capacitance will not be enough to start the microcircuit,

It is rather difficult to determine such an inoperable capacitor by external signs. The small size does not allow you to notice some bulge on its cover. It is possible to measure the capacitance of a capacitor, but often with normal capacitance there is a strong drop in ESR. To check the ESR, special measuring instruments are needed; this cannot be checked with a conventional multimeter or tester.

With voltage drops, the zener diode ZD1 may fail. This can be seen from the darkened (charred) body of the zener diode.

In rare cases, the P4NK60Z field worker may fail. This transistor is supplied with a voltage of 13-15V. from the PWM output. The performance of the field effect transistor can be checked with a multimeter (tester) switched to the diode test mode. On the drain-source channel, the voltage drop is 0.6-0.8 V.

If the voltage at the output of the power supply is 5 V, and when the load is connected, it drops to a value of approximately 2 V., then the electrolytic capacitors at the output of the power supply (C9 and C11) are most likely dried up. To eliminate this malfunction, it is necessary to replace the dried-up electrolytic capacitors with working ones with the same characteristics.

In the general case, the main repair steps can be distinguished. If there is no voltage at the output of the power supply, then it is necessary to check for breakdown by measuring the resistance F1, TR, the rectifier bridge. To provide some start-up margin, it is desirable to use the capacitance of capacitor C6 10 uF and rated for 50v, and not 47 uF and 25v. as usual in the scheme.

In cases where the output voltage drops, unstable operation of the power supply is observed, it is necessary first of all to replace the electrolytic capacitors C1, C9, C10, C11.

In addition, you can recommend a few recommendations to improve the performance of the power supply. At the output of the power supply, a 220 Ohm 0.125w resistor is usually installed, filled with a special sealant. This resistor operates at extreme values ​​and therefore gets very hot. Heating causes the capacitor C9 to dry out. Instead of a 220 ohm resistor, it is advisable to put a 300 ohm resistor and a power dissipation of 0.5 watts. If a 10v capacitor C9 is installed in the circuit, then it is better to put the same one instead, but designed for 16v.

After repair, the body needs to be assembled.But you can not glue it, but fasten the two halves, for example, with a screed, so that in the future, if repair is necessary, it can be easily disassembled again.

While repairing computer equipment, computers and laptops that have already been opened, made by other “unfortunate masters” or a curious user, often get to me for repairs. The consequences of such repairs can be completely different, and if in one case it was simply dismantled, scratched the back of the head and assembled (well, 5-6 screws remained), but at least they didn’t break it, and in the other case they broke it completely and, for example, where it was necessary to change the “severnik” or "Southerner" already needs to change the entire motherboard.

Below are a few examples of self-repairs, as well as non-standard improvements made by "experienced" users.

1. This is how the broken wire of the laptop power supply was repaired, and the person who performed the repair assures that the laptop has been working this way for a year and a half.

2. You can repair the laptop power supply anyway, and the interchangeability of such power supplies, as you can see, is on top.

3. If the BGA chip is not soldered, then of course you can tear it off, then stick it on super-glue, the owner will not even notice)

4. A common computer problem is swollen capacitors. The author of this know-how solved the problem simply, why look for new workable capacitors, spend money, it turns out you can just solder the slots on top and all the repairs are done)

5. And if there are no capacitors of the right size available, you can put others, so what if they don’t fit in size, you can just wrap it with electrical tape, so the master of this repair apparently thought.

6. Here is another innovative way to mount a laptop matrix. "Manly" as they say.

7. Below is a photo of a cooling upgrade, so to speak. More thermal paste and everything is OK. Just think of this.

8. Here is such a way of cooling, it's nice to see)))

9. Modernization of the cooling system, the strong point of some masters. Look at how everything is thought out, and the elongated legs of the laptop look just very stylish)

10. If the drive does not pull out, then it can be pulled out by force. I just don’t know how to pull in order to bend the sled like that, not to mention the broken body.

11. And finally soldering the BGA chip. even probably not BGA (Ball grid array), but WGA (wire grid array)

All of the above is carried out by masters who do not even know what and how is in a computer (except for the last photo, not every master can solder this) and such decisions do not arise at all due to high qualifications. And if, despite all of the above, you still decide to repair the laptop yourself, then remember that eliminating the consequences of self-repair will always be more expensive than repairing the original malfunction.

Repair of Chinese car radios

Repair of Chinese car radios today is more and more interesting for the average user. The question is why?
The answer is clear: almost the lion's share of today's head unit products for cars are made in China. Having become the owner of such a radio (high-quality or low-quality, it does not matter), the user eventually finds himself face to face with a problem.
The equipment deteriorates, loses its sound, or at best, a Chinese car radio firmware is needed. In our article, we will consider the main malfunctions of Chinese car radios and try to explain all the nuances of repair, to give a practical understanding of this process.
Today, everyone knows that the radio is the most common electronic device among motorists. It is very rare to find a car that is not endowed with such a device.
And there is nothing surprising in this. Good music on the road will not interfere with any driver, regardless of his preferences.

Note. Video and CD players are the evolution of such devices today. But despite this, almost the same details and elements remained inside. As a result, the devices are still called car radios and in the case of repair, the process is almost the same.

So, before starting the repair process, you need to provide power to the device.As you know, car radios do not have a built-in power supply, like a music center, and you will have to provide it.

Note. All experts, as one, will declare that it is not recommended to use the battery as a power source in this case.

The most acceptable option would be a mains power supply, ideal for repairing Chinese car radios at home. Such a unit should be able to provide an output voltage of 12-13 V, and the load current should be within 10 A.
On the other hand, the load current may be less, since it is not necessary for the car radio to work at full power during repairs.

Alternatively, you can offer a power supply from a PC. Although the power supply can be made independently, but then you will need to buy a powerful transformer.