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Post by Casethecorvetteman on Apr 14, 2016 6:41:12 GMT -5
Hi all  i have dug the internals out of a failed quad here: You can see there that capacitor has failed:  This is the transformer:  and here is the diagram:  Any ideas on where we could get the required parts or have these made? |
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Post by hulio on Apr 14, 2016 11:13:56 GMT -5
Acquiring the components is not the issue, you can find them for a few bucks/piece. What seems to be more reliable than what Barco used in their quads, are this Ero MKT1815 caps (3000PF 30Kv rated)  and this Tesla diodes (0,1A 30Kv rated, fast recovery rectifying)  The bigger problem is potting them with that special two-components silicone. The main reason why those quads are failing, is not the aged components but the potting silicone getting conductive over time. One should slowly poure the fluid compound while on a vibrating table and than shortly (5 to 10 minutes) let the quad in a vacuum chamber. This is imperative to eliminate all air-bubbles from the silicone. Even we are not able to see them by naked eye, a few microns air-bubble is a huge cave when high voltage is involved. When ready, let it cure for three days @room temperature or, to speed up the process, few hours in the oven @65 degree C. Case, should you want to give a try, there is a company in NSW Australia named Chemtools which sales the special two-components silicone in small quantities too. Call them first (or send a e-mail) and tell them that you need it for high voltage application. Here the link: www.chemtools.com.au/download/technical-and-safety-data-sheets/electronics-production-and-rework/PCT-7000%20Silicone%20Potting%20Compound/PCT-7000%20TDS.pdf |
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Post by dummyload on Apr 14, 2016 14:21:42 GMT -5
Thanks Hulio for that info , it's 3000pf so is 3nf . Maybe first use some spray on the circuit ,something similar to what they use on the sparkplug cables in cars to already make some isolation before potting , maybe the potting is less critical then ? |
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Post by hulio on Apr 14, 2016 14:58:23 GMT -5
Yep, those are picofarad, no microfarad. Thanks.
Edited already.
Yes, some kind of isolating coating on components can't be bad. Good idea.
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Post by Casethecorvetteman on Apr 15, 2016 0:59:40 GMT -5
Thanks for that info Hulio, is there anyone here that is willing to give these repairs a go? I have a few failed quads here that could likely be repaired.
Would it be better to pot them with the resin as used in the splitter?
I have contacted a couple different companies here in Australia, but none of them even reply.
If these quads could be made reliable, we wouldnt have much to worry about for future reliability of the 909/Cine 9
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Post by dummyload on Apr 15, 2016 1:55:38 GMT -5
There must be a reason they use the soft potting , it's the same in the ampro spellman hv supply.
I suspect it is about expanding of components that heat up versus the expanding of the potting , soft potting will match better ?
They used the same hard potting in the splitter and quad in the old analoog projectors (80s')
When it fails again with hard potting digging it out will no more be an option.
Is there a quad in a marguee projector and if so what potting is used ?
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Post by radiohead314 on Apr 15, 2016 4:54:56 GMT -5
With marquee the same potting is used but the quad is housed in the hv supply unit. So it is not a separate thing.
In the industry often oil is used but needs to be clean of airbubbles and other stuff.
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Post by Casethecorvetteman on Apr 15, 2016 6:13:33 GMT -5
Would be great if we could get onto that guy in China that has rebuilt a few quads and have him do some for us, id be happy to pay what he wants for a perfect quad.
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Post by Casethecorvetteman on Apr 16, 2016 0:57:30 GMT -5
With marquee the same potting is used but the quad is housed in the hv supply unit. So it is not a separate thing. In the industry often oil is used but needs to be clean of airbubbles and other stuff. Does the Marquee also have a simular capacitor/diode type setup? What is the purpose of this? |
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Post by gjaky on Apr 16, 2016 2:03:51 GMT -5
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Post by Casethecorvetteman on Apr 16, 2016 2:40:56 GMT -5
Yeah thanks mate, found that not long after i posted the question  So where can we find another one to take the 300v and make it 34.5kV? What voltage drives the Marquee HV supply and how simular is it? Could it be adapted to work? |
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Post by gjaky on Apr 16, 2016 4:06:29 GMT -5
The barco quadroupler in fact is not as simple as its schematic shows, because it has a transformer built in as well which is not shown on the drawing, that makes it replacing the quad with a third party component problematic.
The Marque HVPS requires +390VDC.
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Post by Casethecorvetteman on Apr 16, 2016 5:39:48 GMT -5
Yes i have the transformer sitting here on my lounge room table. There is no reason it cant be reused.
Apart from that transformer, the internals are as per diagram.
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jenum
Junior Member
Posts: 26 
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Post by jenum on Apr 18, 2016 13:02:23 GMT -5
Hi guys, I want to/will try rebuilding quads. Got a vane rotary pump here, however it needs service. Already contacted Leybold, but this could take some time till it's back operating (~1 month). Is there anyone out there that is willing to send me some faulty quads for testing/planing (to germany)? I got no faulty quads here, all working, but if the rebuild will fuction, I want to redo all even the functional ones. Any suggestions what cap typ should be used? PE or PP, dU/dt, voltage vs frequency rating?
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Post by hulio on Apr 18, 2016 14:35:47 GMT -5
My three quads are all working too, but Case already said that he is willing to send a few bad-ones to whoever wants to try. We apreciate your offer. Case mate, put that surfboard away, let that koala alone, give that beer the chance to become cold in the fridge and get I touch with Jenum  ?. Maybe you didn't followed from the beginning Jenum, the caps are ERO MKT1815, 3000PF 30000V rated. |
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