DLP lamp ballast / General Science and Electronics / Forums

Forums

4hv.org :: Forums :: General Science and Electronics

« Previous topic | Next topic »

DLP lamp ballast

1 2 next

Move Thread

LAN_403

haxor5354

Sun Feb 27 2011, 04:52PM

Registered Member #2063 Joined: Sat Apr 04 2009, 03:16PM
Location: Toronto
Posts: 352

does anyone know how to properly drive a DLP lamp? wikipedia says 60 volts to sustain the arc once the arc is started

but with how much current?
I salvaged a DLP tv yesterday and tested the lamp with a flyback transformer, and it seems like it still works. but the ballast unit needs external control to turn it on.
so now im thinking of making my own ballast. any ideas of how limit current so the lamp won't explode. and also how much current would i need?

Adam Munich

Sun Feb 27 2011, 09:34PM

Registered Member #2893 Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242

Well different lamps require different voltages and currents. What lamp is it?

haxor5354

Mon Feb 28 2011, 12:28AM

Registered Member #2063 Joined: Sat Apr 04 2009, 03:16PM
Location: Toronto
Posts: 352

its a RCA265866.
most generic bulbs r rated over 100 watts, so i guess 1 amp at 60 volts wont do much harm

lightlinked

Tue Mar 01 2011, 11:59AM

Registered Member #2087 Joined: Tue Apr 21 2009, 08:32AM
Location:
Posts: 115

you could probably get a cheap chinese UHP (Phillips UHP is a brand name for mercury arc lamp projector bulbs, UHP is like saying Kleenex for a projector lamp) ballast for cheap. there are also many people who grind out their dead bulbs, leaving the dichoric reflector, replacing them with the bare lamp, from china, and cementing them in with high temperature cement.

James

Tue Mar 01 2011, 05:05PM

Registered Member #3610 Joined: Thu Jan 13 2011, 03:29AM
Location: Seattle, WA
Posts: 506

Often times external control is nothing more than an enable line that needs to be pulled logic low or high to turn on the ballast. There are also some status lines that the controller can check to tell what the ballast is doing. I strongly recommend using a proper ballast, these lamps operate at very high pressure and often fail violently. Take care as they produce a lot of UV too, do not operate without a glass shield.

ConKbot of Doom

Tue Mar 01 2011, 05:36PM

Registered Member #509 Joined: Sat Feb 10 2007, 07:02AM
Location:
Posts: 329

James wrote ...

Often times external control is nothing more than an enable line that needs to be pulled logic low or high to turn on the ballast. There are also some status lines that the controller can check to tell what the ballast is doing. I strongly recommend using a proper ballast, these lamps operate at very high pressure and often fail violently. Take care as they produce a lot of UV too, do not operate without a glass shield.

+1 on just looking for enable lines. Look for optocouplers for inputs/outputs. Ive seen a guy get a ballast running by shorting the transistor side of the optoisolaters for the enable inputs. (For a spot lamp, on the currently down candlepowerforums)

mikeselectricstuff

Wed Mar 02 2011, 01:40AM

Registered Member #311 Joined: Sun Mar 12 2006, 08:28PM
Location:
Posts: 253

I've played with these a while ago from a projector.
The enable was somewhat more than a simple enable line - it was via an optoisolator, and it needed a continuous stream of data. I'm guessing this is a safety feature to shut down the lamp to avoid a fire if the fan stops or the main control CPU crashes.
Attatched is some PIC code I used with a ballast PCB marked "Osram VIP" - don't recall the projector make.

Some more info on pinouts etc. here :

Protocol & lamp-start info :

Commands :

and

Note these lamps are quite scary - tons of possibly eye-hazardous UV and need continuous high airflow. The light output from them can melt the plastic of a fan placed too close (guess how I know!). If you have the rest of the projector I'd suggest trying to preserve the cooling parts.

I suspect these lamps may be hard to drive judging by the amount of electronics on the ballast

I think their characteristics change significantly during warmup - the light output certainly does - when they first fire they look like a dichroic halogen, then a few secs later WHOA

as they go in to death-star mode..!

mikeselectricstuff

Wed Mar 02 2011, 01:50AM

Registered Member #311 Joined: Sun Mar 12 2006, 08:28PM
Location:
Posts: 253

Attachment as mentioned above- wasn't an allowed type so disappeared..
]viplamp_asm.txt[/file]

mikeselectricstuff

Wed Mar 02 2011, 01:56AM

Registered Member #311 Joined: Sun Mar 12 2006, 08:28PM
Location:
Posts: 253

Oops - just noticed the above source needs this macro file - can't see any way to add attatchments to a post - mods feel free to merge posts!
]mymacros_inc.txt[/file]

Adam Munich

Wed Mar 02 2011, 02:40AM

Registered Member #2893 Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242

Any tips on finding one of these TVs? I've taken apart about 5 CRT projection screens but no DLP ones and I'd love to play with all the optics in one.

1 2 next

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob