Turning on projector without LD's

[Things]

Well, I have a few empty projectors now, and I've been experimenting to see what I can find, and if there is any way I can get them to power up without any LED's, and wihtout having to use bulky, hot resistors.

I have found the LED and LD's are both controlled from 1 PCB. This PCB gets power right from the PSU, and only has 1 ribbon cable between it and the main PCB. So, the error signals must be travelling through this ribbon cable, so my aim is to try and find it, and trick it into thinking its OK. I have taken some closeup pics. Casio were nice enough to label pretty much ALL the connectors, and even supply a plethora of diagnostic pins, so maybe someone can help interpret anything that could be of help!

We know the projector shuts off with both overtemp and missing diode warnings. So there has to be at least 2 error lines here. Worst case it uses serial communications for error reportings.

Cheers,
Dan

 

[anselm]

Hooray, reverse engineering is so much fun!
Just a hunch, but the pins in the attachment look kinda pomising to me.
That's where I'd start to put an oscilloscope if I had one.
Of course you could just use your soundcard for an oscope:
xoscope for Linux

Also, on the 1st pic, but I'm sure you knew this:
Rx = receive (might be interesting for you)
Tx = transmit

You might want to read
Running the XJ-A140 With Missing Diodes
though I'm sure you already have

 

[HIMNL9]

If you are trying to "fool" the control section, making it think that the LDs array is still connected, remember that, other the current sense from the LDs rows and the overtemp switch, it have also 2 NTC sensors from the array ribbon (they are placed on the LDs side, SMD components, just where the aluminium block have the 2 small silpads)

 

[ped]

A lot of these items have a "test mode" , TV's , videos, projectors ect...that, when enabled, allow you to power up the unit regardless for "testing" purposes ,its usually accessed withe a remote control command, or a jumber on the main PCB. Google it or make enquiries, see if you can do it on these?