Digital Ballast Bypass Expirimenting

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It's hard to say whether the existing circuit (without seeing it) wouldn't have any problems at such a low duty cycle, even at such reduced power.

*second edit*: Well, depending on what you fed from the original ballast board it wouldn't need to run out of normal range anyway..

Do you intend to use HID or LED, and are you thinking of using the existing board as the only ballast, or having it feed another one with input voltage dependent output?

I think the LED ballast would be much simpler, not even any starting mode.
 
Well I managed to get a copy of the "Holy Grail" for this projector....AKA the service manual. Its funny that you were talking about using a PIC to communicate with the ballast. This projector uses a PIC to control all ballast functions.

After studying the schematics and trouble shooting. I figured that the Lamp_Err signal coming out of the PIC was the place to start. This signal is around 70mV and jumps to 5V when a lamp error is detected. This signal is sent through a buffer IC then to the main processor.

http://www.fairchildsemi.com/ds/74/74LCX541.pdf

By cutting the trace from the pic to the buffer and connecting the buffer pin to the buffer ground the projector stays on....

SUCCESS!! So far anyways. I havent tested for more than 2 minutes. I dont know what repeated errors will do to the pic or any other part of the circuit.
Dear crazifunguy, were you able to achieve full success with the digital ballast bypass? I have a ballast that is quite similar to the board you have shown in the pictures. It is in the infocus x10 projector. simple grounding and shorting or resistors havent worked so far. Please help.
 
Hey all! new to join here, read a bit here over the years. hope your all well. I'd like some help if you can "Crazifunguy" if you'r still about. i have what i think is same ballast EUC 200 A/01 china ballast (philips?) it use serial coms. i have had it change its error with attempts to use arduino and another persons code. still wont turn on. anyhow, im over playing with arduino's for a little while, it's getting to me. Been at this NEC VT770 for a few months now and thought it time to ask for some help from those in the know. this after i blew up one unit now on last one. Is it shown in you're pics of this ballast controller board (same as mine) what is the buffer chip and what pin to lift / short to buffer ground? this i need help to id. I'd get a manual for this model if i could. i have tried all companies i can find and none can get hold of it for me on the net or in my land (australia) looks like the projector market is keeping this one locked. if not shown can you please email me a photo or description to work with. Many Thanks for any help you can offer me =) great site here btw, packed full of kool idea's.
 
DLP balast wrong function ?

Very good description, it is possibil to help me ?
At first, sorry for my English.
I have a Thompson DLP, the bulb was died and after the change i have observed that also an optical lense is burned, I have changed it but I do not understand the function for the cooling.
Now the TV works fine but i observed, that after stop, all the coolers are working yet 2 minutes, but the bulb also works.
I think that this is a wrong function, I think that only the coolers should working for a proper cooling, if the bulb does not stop, they can not cooled, so it is non sense.
My balast is the same als your from the picture, it is one EUC 180 A/01.
Can you suggest me an idea what could be wrong, or this is a normal function ?
How can I now if the balast works wrong or the main board and how can I check this ?

thanks
Edyson66
 

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Originally Posted by crazifunguy
Well I managed to get a copy of the "Holy Grail" for this projector....AKA the service manual. Its funny that you were talking about using a PIC to communicate with the ballast. This projector uses a PIC to control all ballast functions.

After studying the schematics and trouble shooting. I figured that the Lamp_Err signal coming out of the PIC was the place to start. This signal is around 70mV and jumps to 5V when a lamp error is detected. This signal is sent through a buffer IC then to the main processor.

http://www.fairchildsemi.com/ds/74/74LCX541.pdf

By cutting the trace from the pic to the buffer and connecting the buffer pin to the buffer ground the projector stays on....

SUCCESS!! So far anyways. I havent tested for more than 2 minutes. I dont know what repeated errors will do to the pic or any other part of the circuit.



scuse me ,what is the pin of buffer .
do you have a photo or something to show as?
ths tks
 
Hello,
I have an Epson EB-W8 projector, that seems to have a serial communication between ballast and projector motherboard. Could someone please help me to get this projector to work without the original bulb. Im hoping to modify it later to be used with LED lightsource.
When the original bulb is not connected to the ballast then the projector starts up, but after a while, it starts blinking red warning leds about lamp problem and shuts down.
Would it be possible to fool this ballast into thinking, that it's loaded with an original bulb even though it is not.
I added some images from the ballast controller board that is removed from the ballast main board.
27053.JPG

27054.JPG

An externally hosted image should be here but it was not working when we last tested it.
 
Well I managed to get a copy of the "Holy Grail" for this projector....AKA the service manual. Its funny that you were talking about using a PIC to communicate with the ballast. This projector uses a PIC to control all ballast functions.

After studying the schematics and trouble shooting. I figured that the Lamp_Err signal coming out of the PIC was the place to start. This signal is around 70mV and jumps to 5V when a lamp error is detected. This signal is sent through a buffer IC then to the main processor.

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By cutting the trace from the pic to the buffer and connecting the buffer pin to the buffer ground the projector stays on....

SUCCESS!! So far anyways. I havent tested for more than 2 minutes. I dont know what repeated errors will do to the pic or any other part of the circuit.

Hi all good people.... i trying to figure this out on my Sony VPL-CX3 it also have p87lpc769 controller... i don't know which pin trace should i cut and what is buffer? is PIC mean p87lpc769? can you be more precious which pin should i cut and how buffer looks like?
 
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