Projector Sharp LED lamp, part 2

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This post is a continuation of 1st post of this conversion, there I made an order for required components. Now that I have all the pieces, I can proceed with it.

Prototype LED+lenses setup
The task is to “focus” light back into 1 spot. Configuration of the lenses I envisioned is in the concept. For a prototype I tried to replicate this 
setup using PVC pipe holders that are sold in hardware shops. Result is a bright square big 5×5 mm in a “focus” about 25 mm away from the last (left) lens. I friend has a Voltcraft MT-52 multimeter, that has an option of a lux meter. I tried to use it for just the focused light. Didn’t get consistent readings. Will use it to measure projector output once assembled.

concept setup_no_light setup_light

Let projector think it is closed (2 switches) and light bulb is working properly
I removed 2 switches, which intention was to check if 1 air filter is inserted and bulb door is closed. They were wires in series and NormalyOpen operation. To replicate them I made a solder bridge on a connector on motherboard.

For the bulb, I need to look in service manual. But should be similar to other projector circuits. Main unit and Ballast PCB are connected 14 pin cable. Main unit receives power (+13v and +6v and GND) for operation on 10 pins. Rest 4 pins carry 3 control (L-POW/SYNC, ECO/LPS, PFC_ON/OFF) and 1 feedback (LAMP is working) signal.
I want MAIN unit to think lamp is working, so I shorted feedback optocoupler (top one). I won’t use lamp power part so I can also desolder 2 input signals for LAMP ON and ECO. With this action I will conserve power.Probably will use LAMP ON for controlling LED ON.

14pin_connector_BALLAST_POWER_unit optocouplers_BALLAST_CONTROL_unit optocouplers


I assemble everything back and hope lamp indicator is now green. And you know I plug in power cord and power indicator lights up green and after that lamp indicator lights green. Jupi… NOT for long. Projector self resets about 1/2 minute later. Hm?? I still don’t have a LED integrated so I cannot see visual output. I know this projector also has a serial communication. Good thing a IBM Port Replicator for my laptop has this option. In Operation Manual I find the settings which are standard (115k baud, 8N1, No) and connect 3 wires (GND, RX and TX) from replicator to projector. But instead of the normal communication, I get some information about error immediately after reset.

terminal window and projector message 3 wires (GND, TX, RX)

What to do now? Did I buy a BROKEN projector? Projector did self reset same before I changed feedback signals for lamp. Should I have tested projector before? I sent e-mail to repair shops for Sharp and hope for the best. But I suspect something is wrong with main chip DDR2000 (FPGA/ARM combo). Will discuss this with seller.

Anything more on this matter in 3rd post. More info about the matter of repair, what is the cause and other info.

Other photos of the process:


Written by luftek

March 28th, 2014 at 4:47 pm

Posted in Make,Repair



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