I’m sorry to hear that your Pioneer VSX-421-K AV receiver is not working. It sounds like you have tried some of the common troubleshooting steps,such as resetting the unit, checking the fuse and the transformer, and replacing the transistors. However, it seems that none of these steps have solved the problem.
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I understand that you’re facing an issue with your Pioneer VSX-421-K receiver not turning on, even after replacing the transistors Q422 and Q417. You’ve also checked the main fuse and transformer, and they seem to be working fine.
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I have 2 Methods for you:
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Given the symptoms you’ve described, it’s possible that the issue might be related to the protection circuit in your receiver. The protection circuit is designed to shut down the receiver if it detects a problem that could potentially damage the unit or cause a safety hazard. This could explain why your receiver turns off after 2 seconds.
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Here are some detailed steps you can take to troubleshoot this issue:
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# [link|https://www.avsforum.com/threads/pioneer-vsx-521-k-821-k-921-k-1021-k-power-on-problems.1447971/page-5|***Check for DC Offset***: The protection circuit can be triggered if there’s a DC offset at the speaker outputs|new_window=true]^^[link|https://www.avsforum.com/threads/pioneer-vsx-521-k-821-k-921-k-1021-k-power-on-problems.1447971/page-5|1|new_window=true]^^. You can check for DC offset by measuring the voltage at the speaker outputs with a multimeter. The voltage should ideally be close to 0V when no audio is playing. If you detect a significant DC offset, it could indicate a problem with the output stage of your amplifier.
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# ***Check the Protection Circuit***: The protection circuit itself could be faulty. It usually consists of a relay and some associated circuitry. [link|https://www.ifixit.com/Answers/View/135121/No+Power+-+not+surge+related|If the relay is not clicking on when you power up the receiver, it could mean that the protection circuit is not functioning correctly|new_window=true]^^[link|https://www.ifixit.com/Answers/View/135121/No+Power+-+not+surge+related|2|new_window=true]^^.
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# ***Check Other Components***: Other components in your receiver could also be faulty and causing the protection circuit to engage. [link|https://www.avsforum.com/threads/pioneer-vsx-521-k-821-k-921-k-1021-k-power-on-problems.1447971/page-5|This includes other transistors, diodes, resistors, and capacitors in your amplifier’s output stage|new_window=true]^^[link|https://www.avsforum.com/threads/pioneer-vsx-521-k-821-k-921-k-1021-k-power-on-problems.1447971/page-5|1|new_window=true]^^. You can check these components with a multimeter or an oscilloscope.
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# [link|https://www.ifixit.com/Answers/View/135121/No+Power+-+not+surge+related|***Check Error Log and Reset***: There’s an error log that can be run and a reset procedure that might help|new_window=true]^^[link|https://www.ifixit.com/Answers/View/135121/No+Power+-+not+surge+related|2|new_window=true]^^. From the OFF/STANDBY state, press & hold [PRESET <–] & [ STANDBY/ON] buttons. Release when the unit powers on. Each press of [ENTER] key displays a protection error count. To reset errors, from OFF/STANDBY state, press & hold the [ALC/STANDARD SURR] & [STANDBY/ON] buttons. Release when the unit powers on. [link|https://www.ifixit.com/Answers/View/135121/No+Power+-+not+surge+related|The unit will display “CLEAR?” Press [ENTER] to reset error and error logs|new_window=true]^^[link|https://www.ifixit.com/Answers/View/135121/No+Power+-+not+surge+related|2|new_window=true]^^.
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Please note that these are advanced troubleshooting steps and require some knowledge of electronics and experience with electronic repair. Always make sure to disconnect your receiver from power before attempting any repairs to avoid electric shock.
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Method 1: (Surface)
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Based on the information you've provided, it appears that the issue with your Pioneer VSX-421-K AV Receiver may be somewhat complex and require a deeper investigation than simply checking for obvious damage or missing components.
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One possibility is that there is an issue with the power supply circuitry or the microprocessor that controls the receiver's functions. To investigate these possibilities, you may need to check the voltage levels on the power supply circuitry using a multimeter, and examine the capacitors and diodes for signs of damage or leakage.
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Additionally, try disconnecting the ribbon cable that connects the front panel controls to the main board, to see if the issue lies with the front panel controls or the ribbon cable.
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If you're still having trouble, it may be worth considering professional repair from a qualified technician who can perform more specialized checks and repairs.
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It is important to note that this is just the surface-level analysis of the issue, and deeper investigation may be required, depending on the results of your checks.
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Method 2: (Deeper)
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The possible issues with your Pioneer VSX-421-K AV Receiver are complex and require a deep understanding of circuitry and electronics. Based on the symptoms you've described, there are several possibilities that could be causing the issue. One possibility is that the power supply circuitry isn't functioning correctly.
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This can be due to a faulty component, such as a capacitor or diode, or due to a deeper issue with the circuitry itself. To investigate this, a technician would need to use a multimeter to measure voltage levels on the circuit board and check for any discrepancies compared to expected levels.
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They would also need to visually inspect the circuitry for any signs of damage or wear. Another potential issue is with the microprocessor that controls the receiver's functions. The fact that the device turns on briefly before shutting off again suggests that the microprocessor may be the culprit.
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In this case, a technician would need to perform specialized checks to determine if the microprocessor is functioning correctly. This may involve removing the processor and testing it in a separate system, or using specialized testing equipment to pinpoint any issues.
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There could also be an issue with the firmware that controls the device's functions. This is less likely, but it's still worth investigating. This could involve updating the firmware if possible, or checking for known bugs or issues with the device's software.
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Overall, accurately diagnosing and repairing an issue with a device like this requires a deep understanding of electronics and circuitry, as well as specialized tools and equipment. It's always advisable to consult a professional technician or support team who specializes in troubleshooting and repairing technical issues. They can provide in-depth analysis, accurate diagnoses, and the necessary technical expertise to repair your device effectively.
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I hope these suggestions will help you fix your receiver. If none of them work, you may need to contact a professional service center for further assistance. Please dont be hesitant to ask if you need further assistance. Have a nice day! 😊
I’m sorry to hear that your Pioneer VSX-421-K AV receiver is not working. It sounds like you have tried some of the common troubleshooting steps, such as resetting the unit, checking the fuse and the transformer, and replacing the transistors. However, it seems that none of these steps have solved the problem.
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According to some online sources, there are a few possible causes for your receiver not turning on or shutting off after a few seconds. Here are some of them:
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I have 2 Methods for you:
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* There may be a short circuit or a bad connection in the speaker wires or terminals. This can trigger the receiver’s protection mode and prevent it from turning on. To check this, you can disconnect all the speaker wires from the receiver and try to turn it on again. If it works, then you can reconnect the speaker wires one by one and see which one causes the problem. [post|816525|You may need to replace or repair the faulty wire or terminal|new_window=true]^^[post|816525|1|new_window=true]^^.
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* There may be a problem with the power supply board or the main board of the receiver. This can cause the receiver to not receive enough power or to malfunction. To check this, you will need to open up the receiver and inspect the boards for any visible damage, such as burnt or bulging components, loose or broken solder joints, or cracked or corroded traces. You may also need to use a multimeter to test the voltage and resistance of the components. [post|816525|If you find any defective parts, you will need to replace them with compatible ones|new_window=true]^^[post|135121|2|new_window=true][post|475794|3|new_window=true]^^.
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* There may be a firmware issue or a corrupted memory in the receiver. This can cause the receiver to not respond or to behave erratically. [link|https://www.techwalla.com/articles/how-to-troubleshoot-a-pioneer-vsx-receiver|To fix this, you can try to update the firmware of the receiver or to reset its settings to factory default|new_window=true]^^[link|https://www.techwalla.com/articles/how-to-troubleshoot-a-pioneer-vsx-receiver|4|new_window=true]^^. [post|475794|To update the firmware, you will need to download the latest version from the Pioneer website|new_window=true][post|475794|^^5^^|new_window=true] [link|https://www.homecinemachoice.com/content/pioneer-vsx-922-review|and follow the instructions in the manual|new_window=true]^^[link|https://www.homecinemachoice.com/content/pioneer-vsx-922-review|6|new_window=true]^^. [post|816525|To reset the settings, you will need to use the front panel controls and follow these steps|new_window=true]^^[link|https://www.techwalla.com/articles/how-to-troubleshoot-a-pioneer-vsx-receiver|4|new_window=true]^^:
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** Switch the receiver into standby.
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** While holding down the TONE button, press and hold the STANDBY/ON button for about three seconds.
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** When you see RESET? on the display, press ENTER.
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** When you see OK on the display, press STANDBY/ON to turn on the receiver.
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I hope these suggestions help you fix your Pioneer VSX-421-K AV receiver. If you have any questions or need more assistance, please let @oldturkey03 know. 😊
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Method 1: (Surface)
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+
Based on the information you've provided, it appears that the issue with your Pioneer VSX-421-K AV Receiver may be somewhat complex and require a deeper investigation than simply checking for obvious damage or missing components.
+
+
One possibility is that there is an issue with the power supply circuitry or the microprocessor that controls the receiver's functions. To investigate these possibilities, you may need to check the voltage levels on the power supply circuitry using a multimeter, and examine the capacitors and diodes for signs of damage or leakage.
+
+
Additionally, try disconnecting the ribbon cable that connects the front panel controls to the main board, to see if the issue lies with the front panel controls or the ribbon cable.
+
+
If you're still having trouble, it may be worth considering professional repair from a qualified technician who can perform more specialized checks and repairs.
+
+
It is important to note that this is just the surface-level analysis of the issue, and deeper investigation may be required, depending on the results of your checks.
+
+
Method 2: (Deeper)
+
+
The possible issues with your Pioneer VSX-421-K AV Receiver are complex and require a deep understanding of circuitry and electronics. Based on the symptoms you've described, there are several possibilities that could be causing the issue. One possibility is that the power supply circuitry isn't functioning correctly.
+
+
This can be due to a faulty component, such as a capacitor or diode, or due to a deeper issue with the circuitry itself. To investigate this, a technician would need to use a multimeter to measure voltage levels on the circuit board and check for any discrepancies compared to expected levels.
+
+
They would also need to visually inspect the circuitry for any signs of damage or wear. Another potential issue is with the microprocessor that controls the receiver's functions. The fact that the device turns on briefly before shutting off again suggests that the microprocessor may be the culprit.
+
+
In this case, a technician would need to perform specialized checks to determine if the microprocessor is functioning correctly. This may involve removing the processor and testing it in a separate system, or using specialized testing equipment to pinpoint any issues.
+
+
There could also be an issue with the firmware that controls the device's functions. This is less likely, but it's still worth investigating. This could involve updating the firmware if possible, or checking for known bugs or issues with the device's software.
+
+
Overall, accurately diagnosing and repairing an issue with a device like this requires a deep understanding of electronics and circuitry, as well as specialized tools and equipment. It's always advisable to consult a professional technician or support team who specializes in troubleshooting and repairing technical issues. They can provide in-depth analysis, accurate diagnoses, and the necessary technical expertise to repair your device effectively.
+
+
I hope these suggestions will help you fix your receiver. If none of them work, you may need to contact a professional service center for further assistance. Please dont be hesitant to ask if you need further assistance. Have a nice day! 😊
I’m sorry to hear that your Pioneer VSX-421-K AV receiver is not working. It sounds like you have tried some of the common troubleshooting steps, such as resetting the unit, checking the fuse and the transformer, and replacing the transistors. However, it seems that none of these steps have solved the problem.
According to some online sources, there are a few possible causes for your receiver not turning on or shutting off after a few seconds. Here are some of them:
* There may be a short circuit or a bad connection in the speaker wires or terminals. This can trigger the receiver’s protection mode and prevent it from turning on. To check this, you can disconnect all the speaker wires from the receiver and try to turn it on again. If it works, then you can reconnect the speaker wires one by one and see which one causes the problem. [post|816525|You may need to replace or repair the faulty wire or terminal|new_window=true]^^[post|816525|1|new_window=true]^^.
* There may be a problem with the power supply board or the main board of the receiver. This can cause the receiver to not receive enough power or to malfunction. To check this, you will need to open up the receiver and inspect the boards for any visible damage, such as burnt or bulging components, loose or broken solder joints, or cracked or corroded traces. You may also need to use a multimeter to test the voltage and resistance of the components. [post|816525|If you find any defective parts, you will need to replace them with compatible ones|new_window=true]^^[post|135121|2|new_window=true][post|475794|3|new_window=true]^^.
* There may be a firmware issue or a corrupted memory in the receiver. This can cause the receiver to not respond or to behave erratically. [link|https://www.techwalla.com/articles/how-to-troubleshoot-a-pioneer-vsx-receiver|To fix this, you can try to update the firmware of the receiver or to reset its settings to factory default|new_window=true]^^[link|https://www.techwalla.com/articles/how-to-troubleshoot-a-pioneer-vsx-receiver|4|new_window=true]^^. [post|475794|To update the firmware, you will need to download the latest version from the Pioneer website|new_window=true][post|475794|^^5^^|new_window=true] [link|https://www.homecinemachoice.com/content/pioneer-vsx-922-review|and follow the instructions in the manual|new_window=true]^^[link|https://www.homecinemachoice.com/content/pioneer-vsx-922-review|6|new_window=true]^^. [post|816525|To reset the settings, you will need to use the front panel controls and follow these steps|new_window=true]^^[link|https://www.techwalla.com/articles/how-to-troubleshoot-a-pioneer-vsx-receiver|4|new_window=true]^^:
** Switch the receiver into standby.
** While holding down the TONE button, press and hold the STANDBY/ON button for about three seconds.
** When you see RESET? on the display, press ENTER.
** When you see OK on the display, press STANDBY/ON to turn on the receiver.
I hope these suggestions help you fix your Pioneer VSX-421-K AV receiver. If you have any questions or need more assistance, please let @oldturkey03 know. 😊