I thought this would be worth writing up, as it raises the possibility that accidentally reseating connectors in the wrong receptacles can cause damage to the Light Source Board (LSB).
This case started when a call appeared in my calendar, the instruction for which was simply to replace a bad Laser Control Board (LCB): part is on site. I later learned that the case had been worked by site staff and the chain's head of IT when the fault first appeared, that Barco had diagnosed a bad LCB, and that when it was established that hardware needed to be swapped out, they scheduled a service call from a certified tech.
When I first looked at the projector, I saw exactly the slate of error messages you'd expect a bad LCB to cause, and so proceeded to replace it. After doing so and installing the right firmware on it, the first lot of errors went away, but then these appeared:
image.png
So something is up with the LSB. The laser plate errors don't make much sense, because either something happened to damage every single plate (the projector is a 12C) in the light source module, or the common denominator is the LSB.
I then noticed that there was a solitary red, solid LED in the middle of the LSB, whereas normally there are blinking green and yellow ones. So I powered down, pulled and reseated all the connections into the same receptacles that I found them, and rebooted. Same problem and errors.
I noticed one other weirdness, too - there was an IMB tamper registering when I first found the projector. Opening up the light engine side cover would not have caused that. So at this point I wanted to know the entire history of what went on with this thing before I came on the scene, and so I called the head of IT. He told me that a site manager had troubleshot under direction from Barco by phone, and that this had included pulling and reseating all the connections to the LCB, LCB, and reseating the CCB. The latter would explain the tamper.
Given that the connections to the LSB had been pulled, I wondered if they'd been put back correctly. In an SP4K-12C, there are several receptacles on the LSB that are unused. I then compared what I found in this projector to one of the others (thankfully this place is a 9-plex and so I had others to compare to), and discovered that he had put one back in the wrong place.
image.png
In the other projector and the service manual, this connector, which is the LCB to LSB control data connection, was in the bottom receptacle. So with high hopes that I was on the verge of fixing the projector, I powered down, moved the connector, then rebooted.
Not only did this not fix the projector, but it caused a slew of new errors.
image.png
Running the troubleshooting steps in the service manual for these errors, the endgame was that we had to replace the LSB as well, which did finally get the projector back up.
I wanted to bring this to everyone's occasion, because the possibility exists that accidentally reseating this connector in the wrong receptacle will damage the LSB such that it needs to be replaced. Of course it could be that whatever took out the LCB also took out the LSB, and my correcting the position of this connector only revealed that fact: the incorrect seating didn't actually cause it. But it could also be that it did.
This is a very rare example of Barco making it possible and easy to reconnect something into the wrong receptacle. They are normally very good at designing that risk out of their projectors. If there are multiple plugs and receptacles of the same type on a board, typically there will be colored markings or legends on the board that correspond to colored zip ties around the wires to guide you to correct positioning. But not with this one, and it is at least possible that getting it wrong can damage the board.
So the moral of the story is to be super careful whenever you have to disconnect and reconnect anything from a Series 4 LSB. In some circumstances, even photos taken before touching it might not be reliable, if someone has worked on it before you and made a mistake. I'm certainly going to look at the photos and diagrams in the service manual before touching one again.
This case started when a call appeared in my calendar, the instruction for which was simply to replace a bad Laser Control Board (LCB): part is on site. I later learned that the case had been worked by site staff and the chain's head of IT when the fault first appeared, that Barco had diagnosed a bad LCB, and that when it was established that hardware needed to be swapped out, they scheduled a service call from a certified tech.
When I first looked at the projector, I saw exactly the slate of error messages you'd expect a bad LCB to cause, and so proceeded to replace it. After doing so and installing the right firmware on it, the first lot of errors went away, but then these appeared:
image.png
So something is up with the LSB. The laser plate errors don't make much sense, because either something happened to damage every single plate (the projector is a 12C) in the light source module, or the common denominator is the LSB.
I then noticed that there was a solitary red, solid LED in the middle of the LSB, whereas normally there are blinking green and yellow ones. So I powered down, pulled and reseated all the connections into the same receptacles that I found them, and rebooted. Same problem and errors.
I noticed one other weirdness, too - there was an IMB tamper registering when I first found the projector. Opening up the light engine side cover would not have caused that. So at this point I wanted to know the entire history of what went on with this thing before I came on the scene, and so I called the head of IT. He told me that a site manager had troubleshot under direction from Barco by phone, and that this had included pulling and reseating all the connections to the LCB, LCB, and reseating the CCB. The latter would explain the tamper.
Given that the connections to the LSB had been pulled, I wondered if they'd been put back correctly. In an SP4K-12C, there are several receptacles on the LSB that are unused. I then compared what I found in this projector to one of the others (thankfully this place is a 9-plex and so I had others to compare to), and discovered that he had put one back in the wrong place.
image.png
In the other projector and the service manual, this connector, which is the LCB to LSB control data connection, was in the bottom receptacle. So with high hopes that I was on the verge of fixing the projector, I powered down, moved the connector, then rebooted.
Not only did this not fix the projector, but it caused a slew of new errors.
image.png
Running the troubleshooting steps in the service manual for these errors, the endgame was that we had to replace the LSB as well, which did finally get the projector back up.
I wanted to bring this to everyone's occasion, because the possibility exists that accidentally reseating this connector in the wrong receptacle will damage the LSB such that it needs to be replaced. Of course it could be that whatever took out the LCB also took out the LSB, and my correcting the position of this connector only revealed that fact: the incorrect seating didn't actually cause it. But it could also be that it did.
This is a very rare example of Barco making it possible and easy to reconnect something into the wrong receptacle. They are normally very good at designing that risk out of their projectors. If there are multiple plugs and receptacles of the same type on a board, typically there will be colored markings or legends on the board that correspond to colored zip ties around the wires to guide you to correct positioning. But not with this one, and it is at least possible that getting it wrong can damage the board.
So the moral of the story is to be super careful whenever you have to disconnect and reconnect anything from a Series 4 LSB. In some circumstances, even photos taken before touching it might not be reliable, if someone has worked on it before you and made a mistake. I'm certainly going to look at the photos and diagrams in the service manual before touching one again.
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