My neighbor asked me if I could take a look at his receiver for him. I don’t know how on earth he did this, but he said he accidentally shorted the neutral and the hot while plugging it in. Not sure how…
Anyways, it’s completely dead, no activity whatsoever. My first thought is the standby circuitry since it won’t even go into standby. I don’t have a schematic, nor am I able to find a schematic.
Here is the receiver
I checked all of the fuses I could find and all measure good. There are two on a board mounted to the bottom board which will be an absolute pain to remove, but could reach the fuses with my meter probes.
The other fuse is on this small side mounted board which I’m assuming is the standby board (don’t work on too many items this new).
I checked the diodes and such in circuit as well as some voltages.
There is a smd bridge rectifier on the back of the board. It’s the larger of the devices.
I’m measuring line voltage across the AC pins, about 123 vac. No voltage on the + or - pins which seems like it would be an issue, but using the diode mode on my meter the rectifier checks out while in circuit. Should I swap it out anyways?
Anyone with experience in standby circuits, any other recommendations as to what to check? Anyone have a schematic? I’ll remove the rectifier from the circuit to test, but any other suggestions would be great!
Thank you,
Dan
Anyways, it’s completely dead, no activity whatsoever. My first thought is the standby circuitry since it won’t even go into standby. I don’t have a schematic, nor am I able to find a schematic.
Here is the receiver
I checked all of the fuses I could find and all measure good. There are two on a board mounted to the bottom board which will be an absolute pain to remove, but could reach the fuses with my meter probes.
The other fuse is on this small side mounted board which I’m assuming is the standby board (don’t work on too many items this new).
I checked the diodes and such in circuit as well as some voltages.
There is a smd bridge rectifier on the back of the board. It’s the larger of the devices.
I’m measuring line voltage across the AC pins, about 123 vac. No voltage on the + or - pins which seems like it would be an issue, but using the diode mode on my meter the rectifier checks out while in circuit. Should I swap it out anyways?
Anyone with experience in standby circuits, any other recommendations as to what to check? Anyone have a schematic? I’ll remove the rectifier from the circuit to test, but any other suggestions would be great!
Thank you,
Dan
Pulled the rectifier and all four internal diodes measured fine on this meter.
Also wanted to add, I found two more fuses. I guess that these small brown devices that look like film caps are actually fuses. There are two on this small board and both measure good.
Dan
Also wanted to add, I found two more fuses. I guess that these small brown devices that look like film caps are actually fuses. There are two on this small board and both measure good.
Dan
I did a look at where the voltage can go, working without a schematic is so much slower lol.
Okay so, the AC comes in through the place and goes into this socket, the solder points are circled in silver.
Other than a couple of caps that go across the line the voltage then goes through this coil as well as a single one of the brown fuses.
It then makes its way to the bridge rectifier, the one I removed and tested. And I do indeed do have line voltage cross the AC inputs of the bridge rectifier, but zero DC on the outputs where there is a 200v cap across the DC lines.
The two solder points circles in black, those go to the primary winding of the transformer. The only way the AC can go to the transformer is if AC from the main plug goes through the glass fuse and to the relay point. Once the relay closes it will complete the circuit, but obviously the relay isn’t closing.
Edit: nevermind, there is voltage at the bridge rectifier, it just isn’t referenced to ground, there is an optocoupler. I measure across the + and - I’m getting 170 Vdc. I’ll keep looking.
Dan
Okay so, the AC comes in through the place and goes into this socket, the solder points are circled in silver.
Other than a couple of caps that go across the line the voltage then goes through this coil as well as a single one of the brown fuses.
It then makes its way to the bridge rectifier, the one I removed and tested. And I do indeed do have line voltage cross the AC inputs of the bridge rectifier, but zero DC on the outputs where there is a 200v cap across the DC lines.
The two solder points circles in black, those go to the primary winding of the transformer. The only way the AC can go to the transformer is if AC from the main plug goes through the glass fuse and to the relay point. Once the relay closes it will complete the circuit, but obviously the relay isn’t closing.
Edit: nevermind, there is voltage at the bridge rectifier, it just isn’t referenced to ground, there is an optocoupler. I measure across the + and - I’m getting 170 Vdc. I’ll keep looking.
Dan
Last edited:
Well to my surprise. There is a 7 pin connector that goes from this board up to the top board that does the processing.
PIN number 3 is labeled as 12v standby and wouldn’t you know it, it has 12v on it.
Not sure if this is the same standby, but I’m guessing it is. Something else is keeping this thing completely dead. No standby or anything.
Dan
PIN number 3 is labeled as 12v standby and wouldn’t you know it, it has 12v on it.
Not sure if this is the same standby, but I’m guessing it is. Something else is keeping this thing completely dead. No standby or anything.
Dan