OzOnE Member Join Date: Dec 2009 Location: Devon Posts: 39 Laser-less mod!!... OK guys, with thanks and respect to krazer and others for taking the first steps on bypassing these PJ's - I've decided to release the info on modding the projectors to work with NO laser diodes at all (and without any huge power resistors!)... I bought some A130 carcasses from Mr Briggs at the beginning of August. It took me about a week to figure out how to bypass the current AND voltage sensing on one of them. I'm sure the A140 will work in a very similar way, but may need tweaking somewhat. I also wanted to try adding the other LED colours to it, so I bought some Green and Blue Phlatlights at the same time. I put some basic code together for sequencing an RGB set of LEDs for these projectors - I haven't tried it yet and it's probably best to save that for another post! As for the mod, I'm sorry I don't have any decent photos at this point because my camera is crappy. I will "borrow" my Dad's camera and get some proper photos up in the next few days. It will make a LOT more sense with photos, but for anyone brave enough to try following the guide in the mean time, well, erm.... Best of luck! There could well be some info missing here as it's been four months since I messed with any of this. Hopefully, it should be correct, but I can't be 100%... Note 1: Remember that there is no temperature feedback from laser block when bypassed! So the fans may run at strange speeds etc. You could change the value of the 10K resistors (for the thermistor bypass) to see if the LD fan speeds change. Note 2: There will still be temperature feedback directly from the Red Phlatlight, so the fans might change speed to a certain extent. It appears to regulate the speed of ALL the fans even with this bypass (not just the one nearest the LED heatsink), but with this in mind... WARNING! - With this mod in place, there is NO guarantee that the LED won't overheat, or that the Laser driver chips / MOSFET's / PSU won't complain or explode at some point! Also, I wouldn't even think about plugging the laser ribbon back in after! There will not be any proper current regulation! (actually, it might even work, but it's very possible that all the laser diodes and / or projector will blow up). So far, my modded PJ seems to behave itself, but... I take absolutely NO RESPONSIBILITY for any damage to person, pride, property, or animals due to trying this mod! The first step is to bypass the two thermistors and the thermal cutoff on the laser block. I'm using small 0805 sized SMT resistors for this. All of the following mods are carried out on the LD / LED driver PCB... Here are the pinouts for the laser ribbon connector (30 pins on my A130's ??)... CN301 (Laser Diode bank conn - NOTE - Actually 30 pins, NOT 24 pins as labelled on the driver PCB!!!)... Pin 1 = THOF (Thermal cutoff) - 100 degree C, normally shorted to TMP-H (pin 5, 3.3V). Pin 2 = TH-L - Voltage divider for Thermistors (ie. "GND")... Pin 3 = TMP-1 - 10K Thermistor 1 on diode block (Spoof with 10K resistor!) Pin 4 = TMP-2 - 10K Thermistor 2 on diode block (Spoof with 10K resistor!) Pin 5 = TMP-H (3.3V for opposite pin of Thermal cutoff). Pin 6 = NC Pin 7 = Laser Diode Bank 1 Anode Pin 8 = Laser Diode Bank 1 Anode Pin 9 = Laser Diode Bank 1 Anode Pin 10 = Laser Diode Bank 1 Cathode Pin 11 = Laser Diode Bank 1 Cathode Pin 12 = Laser Diode Bank 1 Cathode Pin 13 = Laser Diode Bank 2 Anode Pin 14 = Laser Diode Bank 2 Anode Pin 15 = Laser Diode Bank 2 Anode Pin 16 = Laser Diode Bank 2 Cathode Pin 17 = Laser Diode Bank 2 Cathode Pin 18 = Laser Diode Bank 2 Cathode Pin 19 = Laser Diode Bank 3 Anode Pin 20 = Laser Diode Bank 3 Anode Pin 21 = Laser Diode Bank 3 Anode Pin 22 = Laser Diode Bank 3 Cathode Pin 23 = Laser Diode Bank 3 Cathode Pin 24 = Laser Diode Bank 3 Cathode Pin 25 = Laser Diode Bank 4 Anode Pin 26 = Laser Diode Bank 4 Anode Pin 27 = Laser Diode Bank 4 Anode Pin 28 = Laser Diode Bank 4 Cathode Pin 29 = Laser Diode Bank 4 Cathode Pin 30 = Laser Diode Bank 4 Cathode You don't need to worry about the Laser Diode connections, we will be bypassing this elsewhere. On the underside of the board, you can see the labelled test pads for the cutoff signals. First, solder a 10K resistor between the TH-L and TMP2 pads. These should be close enough together to solder the resistor directly between them. The other 10K resistor of course goes between TH-L and TMP1... To save using a wire link, you can just solder one end of the resistor to the TMP1 pad, then carefully solder the other end to the closest side of L305 (this inductor is connected to TH-L anyway). Then you need to bypass the thermal cutoff switch. This is normally closed, but opens when the laser block reaches 100 degrees C... You can simply join the THOF pad to the TMP-H pad with a wire link. Or, if it makes things a bit easier, you can solder one end of the wire to the THOF pad, then the other end to pin 6 of the white connector (CN207). OK, now comes the tricky part. (if you thought the above part was difficult enough, you're not going to like this very much )... You need to remove the four resistors R366, R367, R368, R369 next to IC300. These four resistors normally connect the amplified "laser current sense" outputs from IC300 to the processor (IC112). Then, what we're doing is taking ONE of the outputs from DAC chip IC110 (which outputs the current control signals which go TO the laser driver chips), and looping it back to the processor (IC112) to fool it into thinking everything is normal... Here are the relevant output pins from DAC IC110... IC110 (M62364GP) 8bit, 8 channel DAC - Used to control the current for each LD bank. The OUTPUTS (TO each LD driver) are... Pin 2 (Vout1) TO IC304 pin 16 (CTRL) = LD bank 1 current control Pin 3 (Vout2) TO IC303 pin 16 (CTRL) = LD bank 2 current control Pin 10 (Vout3) TO IC306 pin 16 (CTRL) = LD bank 3 current control Pin 11 (Vout4) TO IC305 pin 16 (CTRL) = LD bank 4 current control And here are the relevant input pins on processor IC112... IC112 (R5F212CASNFP 16bit MPU)... Current sensing... Pin 63 (Analog) FROM IC300 pin 1 (LD bank 1 current sense) via R368 <- Note: I've swapped the pin order here so LD bank 1 is first!! Pin 62 (Analog) FROM IC300 pin 7 (LD bank 2 current sense) via R369 Pin 64 (Analog) FROM IC300 pin 8 (LD bank 3 current sense) via R367 Pin 65 (Analog) FROM IC300 pin 14 (LD bank 4 current sense) via R366 Voltage sensing... Pin 58 (Analog) FROM LD bank 1 Anode (via R112) Pin 59 (Analog) FROM LD bank 2 Anode (via R111) Pin 60 (Analog) FROM LD bank 3 Anode (via R110) Pin 61 (Analog) FROM LD bank 4 Anode (via R109) The "current control" output voltage from IC110 is close enough to what IC112 expects to see on it's "current sense" inputs, so we can just take the pin 2 (Vout1) output from IC110 and connect it directly to pins 62-65 on IC112... You COULD attempt soldering one side of the pads where you removed R366-R369, as these connect directly to pins 62-65 of IC112, but I did it another way... Basically, each of the "current sense" / "voltage sense" pins on IC112 have a small capacitor on them which then connect to Ground (for smoothing I guess)... These are caps C125, C127, C128, C130 for "current sense" pins 62-65 respectively. And caps C120, C121, C123, C124 for the "voltage sense" pins 58-61 respectively. The ends of each cap pointing TOWARDS IC112 are what we're interested in - the outside ends of the caps all connect to Ground! So instead of trying to solder directly to the pins of IC112, what I did is to use a VERY small single strand of wire to connect one side of C125, C127, C128, and C130 together. Then, use a wire link to connect from pin 2 (Vout1) of IC110 to your new wire bridge between pins 62, 63, 64, 65 of IC112. That should be the current sensing bypassed! (btw, I found it easier to solder to the pad of the missing R187 instead of soldering directly to pin 2 of IC110. You should be able to see which side pin 2 connects to.) The voltage sensing was a bit more involved. You see, the processor expects the voltage on these pins to be slightly lower than for the current sense signals. I tried connecting them directly but it didn't work (PJ shut down)... You need to first connect pins 58, 59, 60, 61 of IC112 together (again using a strand of wire to connect one end of C120, C121, C123, then across to C124). Then we need to form a voltage divider using two resistors to drop the voltage slightly... First, I soldered a 390 OHM resistor between the wire bridge on the "current sense" caps and the wire bridge on the "voltage sense" caps. Then solder a 1K resistor between the "voltage sense" caps and Ground (you can solder directly in parallel with C121 for example). I think that pretty much covers it. There may be differences between projectors, so I can't guarantee that this will work for everyone. Again, this mod has only been tried on ONE A130! If your PJ keeps cutting out (turning off), you might need to play around with different resistor values for the voltage divider. If you also want to bypass the door-switch, just solder a blob across the pins of CN901 on the main board (should be labelled "COVER"). It goes without saying that you should watch out for the mains voltages in the power supply though! I will try my best to get some photos up soon, plus a decent photo of the driver PCB with the mod sections labelled. More soon, OzOnE. Last edited by OzOnE; 12-13-2011 at 10:26.