Digital Ballast Bypass Expirimenting - Page 3 - diyAudio
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Old 25th August 2010, 12:36 PM   #21
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Join Date: Nov 2005
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.
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Old 25th August 2010, 12:45 PM   #22
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Join Date: Nov 2005
With optics and firmware designed for filament illumination, would it be difficult to get the right color balance with an LED source?
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Old 25th August 2010, 06:29 PM   #23
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Originally Posted by Andrew Eckhardt View Post
With optics and firmware designed for filament illumination, would it be difficult to get the right color balance with an LED source?
From the LED mods I have done this really doesnt seem to have any effect. The optics are happy as long as they get light. The origional lamp was Metal Hallide not filament.
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Old 3rd September 2010, 02:22 AM   #24
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just curious as to which projector you used for this mod? im very interested in this to say the least.
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Old 8th September 2010, 11:45 PM   #25
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Check out some of my other posts or see where all my future projects will be..
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Old 3rd November 2012, 02:06 PM   #26
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Originally Posted by crazifunguy View Post
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.

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.
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Old 19th January 2014, 11:14 AM   #27
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Join Date: Jan 2014
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.
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Old 31st May 2014, 06:28 PM   #28
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Join Date: May 2014
Location: Romania
Question 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 ?

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