CurtPalme.com Home Theater Forum

BTaylor944 · Joined: 21 Feb 2008 Posts: 20

I just got my Dwin HD700 up and running. The picture looks pretty good but I'm a little disappointed by the noise the projector puts off. First, the fan on the power supply seems to have gotten louder in the last few days. Initially I could barely hear it but now I can definitely hear it during quiet scenes in a movie. It's still pretty low, but I do wonder why it seems louder than a few days ago.

Also the projector emits a high volatge crackling or popping sound that is often quite distracting. Could this be the result of the new tubes that were just installed? If so, will the sound decrease as the tubes are broekn in?

Any information on the fan noise or the electric crackling would be greatly appreciated.

Thanks,
Bruce

**Curt Palme** · Posted: Tue Mar 04, 2008 6:35 pm Post subject:

Chances are the HV section of the power supply is arcing, I've seen that before. You need to open the set quickfast to find out the source of the arc. Running it like that can nuke the set, and worst case, spot burn the tubes that you just put in.

BTaylor944 · Joined: 21 Feb 2008 Posts: 20

It's more of a popping sound than an arcing sound. It seems to be coming from the back of the tubes. All three tubes seem to be making the sound. It's a crackling or popping as opposed to a buzzing. In some old reviews of the HD700, I've actually read that other people have also experienced this sound with the HD700. I thought it might be because the tubes are new or something like that.

If it is arcing as you suggested, how would I know for sure?

**Curt Palme** · Posted: Tue Mar 04, 2008 7:07 pm Post subject:

You'd see a flash or something either at the front of the set where the power supply is, or on the tube necks/sockets. Are they new tubes or VDC rebuilds?

BTaylor944 · Joined: 21 Feb 2008 Posts: 20

No flash or anything like that. They're new Delta 145 lenses. It really just sound like normal crt electric sounds but louder and the sounds continue even after the projector warms up. The sound is eminating from the back of each tube where the neck widen into the phosphor area.

**Curt Palme** · Posted: Tue Mar 04, 2008 8:31 pm Post subject:

So you changed the lenses, not the tubes? They are not the same thing...

BTaylor944 · Joined: 21 Feb 2008 Posts: 20

The previous owner had the work done by Dwin. He said they changed the CRTs, so I guess that really means the tubes, not the lenses. Would new tubes make a crackling sound until they are broken in?

**kal** · Posted: Tue Mar 04, 2008 8:41 pm Post subject:

New tubes will often make an occasional crackle as they break in.

Kal

BTaylor944 · Joined: 21 Feb 2008 Posts: 20

It's not really occasional crackling. It's pretty constant. I'm hoping it subsides as the tubes break in. How long does it generally take a new tube to break in?

Thanks

**kal** · Posted: Tue Mar 04, 2008 9:52 pm Post subject:

As long as a few hundred hours I've heard.

It shouldn't be a consistent crackling however. During the first few hundred hours you might get an occasional crackle (every 5-30 minutes let's say). If it's constantly crackling that doesn't sound right.

Maybe one of the tube experts will chime in.

Kal

**Curt Palme** · Posted: Tue Mar 04, 2008 10:02 pm Post subject:

I would pop the top cover and look in it with the room pitch black. A DWIN is supposed to be almost slient save for the fan. NO reason for the set to crackle. I install a lot of new tubes, and don't get that. Once in a while a tube will arc internally, but that should not be a constant thing.

I'm going to bet you see some arcing somewhere.