Hi all,
Folks here have helped me a time or two before. I have another device I'm trying to fix. The house it was in got hit with lightning or some sort of large serge. Since then it won't power up at all. I don't hear a 'click' when I press power. I've checked the fuse that is inside the case right below where the power cord plugs in and it has like 1.8 Ohms. So I'm guessing that is good. From the block diagram I gather that it should have a relay that kicks on. Looking at the parts list it looks like the relay is RY91. I see that on the circuit board here:
Here it is in my system:
Is there a way I can test this relay? It appears to have some sort of little button on top? Any ideas what that may be?
Any suggestions or tips in general for trying to bring this guy back to life? I've also uploaded the service manual if that help.
Thanks for any suggestions!!!!
- Craig
ps. manual is also here: http://www.bluefoxnet.com/files/Marantz-NA-7004-Service-Manual.pdf
Folks here have helped me a time or two before. I have another device I'm trying to fix. The house it was in got hit with lightning or some sort of large serge. Since then it won't power up at all. I don't hear a 'click' when I press power. I've checked the fuse that is inside the case right below where the power cord plugs in and it has like 1.8 Ohms. So I'm guessing that is good. From the block diagram I gather that it should have a relay that kicks on. Looking at the parts list it looks like the relay is RY91. I see that on the circuit board here:
Here it is in my system:
Is there a way I can test this relay? It appears to have some sort of little button on top? Any ideas what that may be?
Any suggestions or tips in general for trying to bring this guy back to life? I've also uploaded the service manual if that help.
Thanks for any suggestions!!!!
- Craig
ps. manual is also here: http://www.bluefoxnet.com/files/Marantz-NA-7004-Service-Manual.pdf
Looking at the diagrams some more... Would it make sense that the relays I've circled here are the same?
Researching this, I think the Standby SMPS component is a switched mode power supply. So, it could make sense that it is always powered up, and creates a low voltage rail to run the relay to turn on the main analog transformer.
I was thinking transformers only really worked with AC power. however, searching the web it said that a SMPS first stage rectifies the power to DC, then second stage reduces the voltage.... assuming that is correct In order to do that would it need to create some sort of sign wave in the signal to cause the transformer (2nd stage) to work? Or am I way off. Just trying to understand the components a bit better so I can pick some points to check for function. Can't really check for function if I don't know what I should expect at that point. 🙂
Thanks for any thoughts/help. Again, just trying to use this as a learning project. If the patient dies... it dies... was headed for scrap anyway.
Researching this, I think the Standby SMPS component is a switched mode power supply. So, it could make sense that it is always powered up, and creates a low voltage rail to run the relay to turn on the main analog transformer.
I was thinking transformers only really worked with AC power. however, searching the web it said that a SMPS first stage rectifies the power to DC, then second stage reduces the voltage.... assuming that is correct In order to do that would it need to create some sort of sign wave in the signal to cause the transformer (2nd stage) to work? Or am I way off. Just trying to understand the components a bit better so I can pick some points to check for function. Can't really check for function if I don't know what I should expect at that point. 🙂
Thanks for any thoughts/help. Again, just trying to use this as a learning project. If the patient dies... it dies... was headed for scrap anyway.
Hi
If the device was power then all semiconductors (especially the ICs) could be suspected.
If the device was in standby, then you should look at all the standby circuits.
If the lightning came through the power cable, probably destroyed IC95 and now you have no +6V CPU voltage.
If the lightning came through another cable (like network) then any voltage regulating circuit or/and digital circuits, IC could be fried.
Anyway, you should start with checking STANDBY SMPS branch voltages, the +6V CPU voltage; if that is present then check the 3.3V voltages, 3.3V CPU voltage, the 1.2V voltage, the 5V voltage (all coming from +6V CPU). See also TROUBLE SHOOTING 1. OLED doesn't light, in the manual.
If you are lucky you may find one of those LDOs bad (one voltage missing), you replace it and you're done
If you have bad luck, the surge destroyed the microprocessor.
Many times, lightning destroyed more than one component. Don't be discouraged by that 🙂 , first do this simple thing check if standby voltages are ok.
I doubt the relay was the one affected by the surge.
If the device was power then all semiconductors (especially the ICs) could be suspected.
If the device was in standby, then you should look at all the standby circuits.
If the lightning came through the power cable, probably destroyed IC95 and now you have no +6V CPU voltage.
If the lightning came through another cable (like network) then any voltage regulating circuit or/and digital circuits, IC could be fried.
Anyway, you should start with checking STANDBY SMPS branch voltages, the +6V CPU voltage; if that is present then check the 3.3V voltages, 3.3V CPU voltage, the 1.2V voltage, the 5V voltage (all coming from +6V CPU). See also TROUBLE SHOOTING 1. OLED doesn't light, in the manual.
If you are lucky you may find one of those LDOs bad (one voltage missing), you replace it and you're done
If you have bad luck, the surge destroyed the microprocessor.
Many times, lightning destroyed more than one component. Don't be discouraged by that 🙂 , first do this simple thing check if standby voltages are ok.
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