Help needed re. replacement bulb & ballast in Samsung DLP

I have a 61" Samsung HLM-617WX/XAA that I purchased in early 2003. This was one of the very first DLP sets on the market, and it has worked perfectly until last week when the original bulb finally gave up the ghost after nine years (there were lots of tiny glass pieces inside the bulb).

So I first tried replacing only the bulb. Not an easy task, because there are no labels or stickers anywhere on this set (inside or outside) indicating what bulb is required. But after removing the blown bulb from the housing, I determined that the original was an Osram P-VIP 120/1.3 E23, made in Germany. The lamp housing has Toshiba connectors (vs. the more common Philips), and the ballast is the Osram PT VIP 120AC/380 01... also known as the Samsung BP47-0003A.

I ordered a genuine Philips bare bulb (Philips E23 100/120W 1.0) and installed it in the housing. But no joy when I turned it on. The lamp did not fire up. (The only difference is that the new bulb has a 1.0 gap vs. 1.3 in the original, but the supplier insists that either will work fine and the 1.0 gap simply provides longer bulb life. This seems correct, because I've seen the same thing on other websites.)

Figuring that a bad ballast was the most likely culprit, I ordered a genuine Samsung BP47-0003A replacement which was absolutely identical to the original. And because my color wheel had been making a little noise over the last year or so, I took the opportunity to replace it as well while I had everything ripped apart.

When I powered up the set, it made all the usual startup sounds but the lamp still won't come on. The ballast is receiving a steady 380VDC from the moment the set is turned on. It's also getting the 5VDC trigger to fire up the bulb, immediately after the color wheel has spun up. So why won't the lamp fire??

To be absolutely certain that I didn't receive a defective bulb, the supplier sent me a replacement - but it won't come on either.

Per the service manual, it seems like everything is normal and I'm totally frustrated. I've now replaced the bulb (twice), the ballast, and the color wheel, but still can't get the bulb to come on. The set makes one loud click immediately after hitting the power button (as it always did); the four-note tune sounds, the color wheel spins up, and the 'lamp' light on the front begins to flash slowly (as it always did). But rather than seeing the bulb come on a few seconds later, the set attempts the startup sequence three times before giving up and displaying the dreaded three lights. Watching the ballast with the back off of the set and the safety interlock taped into position, I see a white light flashing rapidly inside a cylindrical component on the ballast board, accompanied by a faint and rapid clicking sound when the ballast receives the 5V trigger. This lasts about 3-5 seconds. But there's nothing at all from the bulb.

There's just not many moving parts involved here, and I've replaced all of the usual suspects. What I can't understand is how a brand-new ballast can't fire a brand-new lamp, when the ballast is receiving both 380VDC power as well as the 5VDC trigger. My understanding is that the 5V won't appear if any of the other components (DMD, color wheel, temp sensor, etc.) don't report that they're operating normally. So what am I missing here? Any suggestions welcomed - I really need help here!

Thanks...

:(Bill,
Thanks for the reply. Good suggestion re. the temp sensor. A local repair tech I spoke with also mentioned the overheat switch, and said that if it failed, the lamp wouldn't fire. I don't think that's the problem because I've never had the overheat indicator come on, but just to be 100% sure, I'm going to try jumpering across the switch.

Just to clarify for everyone's safety: Please do NOT attempt to "connect to the leads of the bulb" to check voltage! If it's working properly, the ballast provides a 10,000 VAC charge on those heavy black leads to jump-start the mercury vapor lamp. That's dangerously high voltage, and would also blow out any meter you might connect. The voltage that is safe to check is across the brown and blue wires that come from the power supply and plug into the ballast board, which should read about 380V immediately after the set is powered up. It's also safe to check for 5VDC across the thin blue & white wires also plugged into the ballast. This will read zero when the set is first powered up, and should then jump to 5VDC after the set passes its boot-up tests and the color wheel has come up to speed. That 5VDC is the "trigger" signal that tells the ballast to go ahead and fire the lamp. (Both of those voltages are fine on my set, but the stupid lamp still wont come on.)

I was still on my original Osram bulb from late 2002, believe it or not. I must have been really lucky to have it last almost ten years... although, like yours, mine was taking a bit longer lately to get to full brightness. So when it finally went out, I felt 100% certain that all I needed to do is replace the bulb which was obviously blown (little bits of glass were rattling around inside). That's why it's so frustrating that I just can't seem to fix it, even after trying two new bulbs, a new ballast, and a new color wheel!

I hear 'ya re. the low cost of new sets vs. the $5k I had to pay way back then (and that didn't even include the special matching stand). If I hadn't already invested so much trying to get this one running again, I'd probably have gone that route. In the end, I may still end up having to throw in the towel and buy a new tv.

No - about the only thing I haven't tried. The carrier is in fine shape, and the connectors are working fine (I've even checked continuity on the two leads all the way from the ballast to the lamp.)

I installed a genuine Philips lamp which is a precise replacement for the original Osram bulb. Because this was literally one of the very first DLP sets shipped by Samsung in the U.S., there are no stickers or labels anywhere (inside or outside) to indicate the correct replacement bulb... and Samsung used several different bulbs and ballasts in the HLM617W. So I removed the actual bulb from the carrier, and matched the model stamped on the old bulb. Samsung sells several different bulb/carrier models starting with BP96-0224 followed by a letter (A, B, etc.). Turns out that they all use the same internal bulb; the different letters simply designate the manufacturer and the type of connector on the carrier. My original was a 120W E23 Osram bulb with a 1.3 mm gap. The new ones today are all 100-120W, with a 1.0 gap. Everyone (even Samsung) says the 1.0 gap will work fine, and simply lasts longer - that's why it's hard to even find this bulb with a 1.3mm gap anymore. And I was careful to get the E23 vs. the E23H, which needs a much higher voltage to start than the E23.

Have I missed something here?? I've had the same concern that perhaps I didn't get the correct bulb, but I've researched this to death and always conclude that I have the right one. And it's a genuine Philips, not one of those cheap imitations...