CurtPalme.com Home Theater Forum

RVonse · Joined: 09 Mar 2006 Posts: 3152

I use to think my days of running my BG1209 would only be limited to finding tubes but now I'm wondering if I will run out of spare quads first. I just blew another quad yesterday so thats it for my spare parts and over 6 years I've gone through 4 of them now. I have about 20450 total run time on my projector.

I have seen other posts on this site about people who have had trouble finding quads so I know they are very scarce. Is my Barco destined to be a dinosaur and should I give up on it if another quad goes south?

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

One of the members here has had success rebuilding them. I'm not at liberty to say who . But if they see this thread they might chime in or send you a PM.

I think Curt should have some though.

Nashou

**Curt Palme** · Posted: Fri Nov 02, 2012 2:35 am Post subject:

I've got good stock on 1208/1209 quads, am very low on 808/Cine 7 quads.

Let me know if you need one, they fail due to age and the HV involved. Internal arcing, same as any HV power supply.

km987654 · Posted: Fri Nov 02, 2012 4:03 am Post subject:

**Curt Palme** · Posted: Fri Nov 02, 2012 4:08 am Post subject:

Electrically, nothing, it's the leads coming out of the top vs the sides, and the bottom mounting bracket. You can't swap the two without forcing them to fit, which is never a good idea when dealing with 34Kv.

RVonse · Joined: 09 Mar 2006 Posts: 3152

RVonse · Joined: 09 Mar 2006 Posts: 3152

Ile · Posted: Fri Nov 02, 2012 12:03 pm Post subject:

I guess that also climate might have some effect to this issue, I have feeling that old quads doesn't like humid environments.

Here humidity is pretty low and quads seem to last forever. During decade playing with Barcos I haven't lost any quads or any other HV parts. I remember only about two Barco quad fail around here in last decade.

Or maybe I just have had good luck this far.

WTS · Joined: 08 Mar 2006 Posts: 1276 Location: Calgary

As far as having success in rebuilding the quads, you can ask Curt how many of the ones I rebuilt are still working. I can tell you that rebuilding them is a real pain and there's no real telling now long they will last or if they will even work after you get then repotted. That HV stuff is tough to work with, and repotting them is very critical to the success, even having a vacuum chamber never ensured success with the potting. Not to mention that the potting compound was very expensive and proper replacement caps are hard to find and not cheap.

In my opinion the reason they go bad is because the voltage rating on the internal caps is too low, they should be alot higher. Of course if they'd designed them like that they wouldn't make any money on selling replacement quads.

RVonse · Joined: 09 Mar 2006 Posts: 3152

WTS · Joined: 08 Mar 2006 Posts: 1276 Location: Calgary

Not screwing down the quad won't make any difference in my opinion, it doesn't require a heat sink, the unit itself is not conducive to conduting heat out of the case as RTV doesn't conduct heat very well would be my conclsuion on that. Humidity, I'm not sure about that part because I'm not sure what type of RTV compound they used and whether it's affected by humidity.

As for disassembling these units, like I said earlier, it's a real pain in the butt, very tedious work and if you slip you could damage a component or worse damage the transformer winding. After you've done a few you get to know where parts are located inside the case and where not to put your digging tool. As for trying to use an off the shelf flyback, forget it, Scott and I looked for something that might work but couldn't come up with anything between the two of us.

What's in the box, yes there is a flyback transformer and caps and diodes, that's it. The caps and diodes are between 2 parallel circuit boards with potting compound completely surrounding(encapsulating) everything, thus the fun digging it all out from between and around each component in order to repair it. You need to get at the caps connections to check them to see if they've gone bad. Sometimes you don't even need to check them because it's plain to see they were burnt through the side because of HV.

Then comes the task of re-potting. First you need HV potting compound which is usally a 2 part mixture (expensive) and then pouring it into the case and ensuring there is absolutely no entrained air, thus the reason for the vacuum chamber. Then cross your fingers and hope that you got all the air out before the compound sets up. Then cross your fingers and toes when it comes to firing it up because if you didn't get all the air out HV likes to travel to parts it's not suppose to, it likes short cuts let's say, then it either works or goes puff.

Good luck I hope you have success.

km987654 · Posted: Sat Nov 03, 2012 8:29 am Post subject:

WTS · Joined: 08 Mar 2006 Posts: 1276 Location: Calgary

I don't think you'll get any humidity into the internals unless the RTV is cracked really. I'm sure over time the RTV can dry out from the continous heat cycling inside the projector. Alot of these quads have gone bad without any visible signs of damage like cracked RTV, not to mention some have gone bad in projectors with low hours on it. I had a quad go bad in my Zenith1200 pro and it only had about 3k hrs on it at the time. I don't think it's a problem with the SMPS as the Barco supplies are pretty reliable and simple design for the HV system. As far as being engineered for a certain lifespan, that's a factor of parts quality and over engineering factor, I think these very simply under engineered, if they had simply put in higher voltage rated caps I doubt you'd be seeing these many failures. Not all electronics are designed to fail at some point and the extra costs to upgrade the caps would have been minimal.

RVonse · Joined: 09 Mar 2006 Posts: 3152

WTS · Joined: 08 Mar 2006 Posts: 1276 Location: Calgary

Just knowing the function of the splitter I would think not.

barclay66 · Posted: Mon Nov 05, 2012 3:17 pm Post subject:

**Curt Palme** · Posted: Mon Nov 05, 2012 3:30 pm Post subject:

The one thing you're all forgetting is that these sets are now 15 years old. Why does a radiator hose break? Why does an MP3 player break?

This isn't rocket science! THe later Barco quads had crappy potting material that went conductive after a number of years. The older ones seem to be better, but yes, caps, resistors and diodes break, and the silicone compound on the older ones break down as well over time.

It would be great if someone could re-engineer or reverse engineer the quads, but I think the cost would be prohibitive. That's why BArco wants between $800-1200 per quad new, depending on who you talk to apparently.

**AnalogRocks** · Posted: Tue Nov 06, 2012 2:15 am Post subject:

Hey would spraying the quad down with silicone spray help keep the moisture out?

**Curt Palme** · Posted: Tue Nov 06, 2012 3:06 am Post subject:

I doubt it. I'm not sure if it's moisture or if it's simply a breakdown of the existing silicone. No question that most of hte newer quads have a softer silicone than the older ones. The older style seem to become brittle, the newer ones stay soft and are easier to cut into.