CurtPalme.com Home Theater Forum

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

It's my understanding that the problem with the quads is that the components in them break down over time at the high operating voltage.

I don't know if it's actual voltage related failure or if it's a secondary effect that leads to the failure.

The voltage quadrupler itself is really a ladder network of a few capacitors and a few resistors and the whole affair is potted
for safety and to exclude any moisture from the circuit. Of course it must function as a VERY good insulator.

I wonder if the potting compound used might possibly be insufficiently water-resistant. Perhaps it slowly absorbs moisture
from the air and starts to cause breakdown.

If I had a dead quad to investigate, I just might attempt to rebuild one for an experiment.

I think that the potting is the critical part of the operation. Use the wrong compound and the rebuilt assembly will fail.

redfox001 · Joined: 16 Mar 2009 Posts: 2257 Location: The Netherlands

Yes it seems the kit is not very time resistant but also the electrolytic caps used have chemicals that tend to get worse with time. If you use them the wrong way around they wil explode as electrolysis starts making hydrogen gass that explodes the cap.

So you have to reformat old electrlolytic caps slowly. But the kit issue is more troublesome. I buy old quads from 808's

**Curt Palme** · Posted: Wed Jul 19, 2017 1:37 pm Post subject:

I put in the older style quads in almost every 909 I sell. I don't buy that recapping any other board incl the EHT will save quadruplers, the problem is inherent to the potting compound, probably absorbing moisture over time like Chris says. I did notice that the newer quads' potting compound stays soft over time, the older quads harden up.
I have a ton of the older style quads, probably 20-30 of them, tested and working, so there's no shortage of supply.

digitalayon · Joined: 02 Mar 2009 Posts: 921

Curt,

is your price with shipping or without?

-Andy

**Curt Palme** · Posted: Wed Jul 19, 2017 3:09 pm Post subject:

You're kidding, right? WITHOUT! (local pickup is free).

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

I think I should mention that I may also be able to help out with the lenses if they are needed. If Curt runs out,
I have a few sets I could probably bear to part with. But Curt gets all sales first!

I have HD-10Ls (3M type), GT17s, and Fs. At least. But I am keeping both sets of my treasured Elcan-made VDC HD10Ls.

justin_f · Joined: 27 Nov 2010 Posts: 52 Location: Australia

I was told by a Barco tech that the 909/919/CineMax & Cine 9 quads often fail prematurely because the wires coming out the back get squashed when fitting them.

The tech stated in the past Barco put silicon on them, but not in the later ones... if you put tape and make sure all yellow, white and black wires are not squashed, the quad should last a long time... (his exact words, not sure where you put the tape).

This tech stated he did this to the late model quads and had one last as long as 17,000 hours.

I havent had a look at my quads to see what he is talking about, but theres merit in this. I noticed the quads in my 909s are from another model Barco set and the wires come straight out and not flush like the later model quads? The quads I have fitted in my 909s cannot sit flush and have a long wire coming out of them.

Regards,

Justin.

mp20748 · Posted: Sun Jul 23, 2017 8:48 am Post subject:

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Interesting. I might suggest that it could be worthwhile to coat the exposed surfaces of the potting compound with something that is itself a highly effective moisture barrier. Perhaps certain epoxies, or epoxy paint.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

So how are things going with this possible mass purchase of 909s?

If anybody's thinking of getting one from Curt and then, if need be, getting tubes for it from me, I'd like to have some advance notice so I can get my ducks in a row.

**Curt Palme** · Posted: Tue Jul 25, 2017 11:21 pm Post subject:

At this point, given the lack of committed people, they will end up going to the recycler. It won't happen for a couple of months yet, so I may do a emailer to see if any of the 15K people on the mailing list are interested. No sense in spending $3K on shipping alone, let alone the purchase price and customs for them to sit here for the next 5 years..

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

So let's start a Save the 909s topic!

And if that fails, clue me in on where these units are. Maybe I'll just be NUTS enough to bid on them but not against you.

Reddman · Joined: 28 Feb 2007 Posts: 70 Location: South Carolina

I'm up for purchasing one and I'm fine with waiting several months for one as I'm currently in the process of moving.I hope others are willing to take advantage of this great opportunity.

**Curt Palme** · Posted: Wed Jul 26, 2017 1:37 pm Post subject:

I think I already said above, I have two chassis here with worn tubes ready to ship, I'd just need to box them up and test run them for 24 hours before shipping. Let me know when you're ready. The next 2 months are going to be hell with sound installations anyway, so the less I have on my plate the better. Smile

I still have two 909s here that I need to retube and sell as full working sets to boot.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

I'm saving my shekels to pay for that, believe me. I'll let you know as soon as I've reached that point.

But, in any event, if you decide not to pursue this lot of 909s, clue me in on where they are because I just might be
crazy enough to go for the lot.

Pokemon640 · Joined: 28 Jul 2015 Posts: 49 Location: Greece

mp20748 · Posted: Fri Oct 06, 2017 10:27 am Post subject: