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Post by Casethecorvetteman on Feb 26, 2016 23:03:14 GMT -5
Hi all, i have seen these schematics somewhere before, but not sure where.
I have contacted an electronics manufacturing company here in Australia about their services, whether they can make the units complete or pot them after repair and test, waiting to find out.
Also does anyone have the schematics for an NEC splitter or HV tranny? Id be really interested to know is someone here could make this work in a barco!!
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Post by Casethecorvetteman on Feb 26, 2016 23:35:59 GMT -5
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Post by gjaky on Feb 27, 2016 2:47:18 GMT -5
splitters are of a quite dumb components, usualy there is nothing inside them only a current limiting resistor and a filtering cap and sometimes an additional resistor that forms a voltage divider (in barco with with the little variable resistor), in the NEC it goes to the HV PWB.
The Barco QUAD contains a HV transformer and a so-called Villard voltage multiplier (capacitor-diode multiplier). In the NEC they use a more conventioinal FBT actualy two similar to what you find in other CRT displays. These transformers are generating high voltage with coil-diode networks in series.
Since the NEC uses double transformer it needs double drive too opposed to Barco.
The HV boards in the NEC changed only a little, because of size constraintts the XG's HV board wouldn't be an ideal choice for the Barco. A PG (xtra) board is much smaller. However there are other problems. The Barco EHT runs from 300V supply the NEC board runs from 150V supply.
The NEC HV output may turn out to be not enough powerfull. For reference the XG's HV output is 32kV@ 3.2mA. I don't know about the Barco, but the Marquee has 34.9kV and 3.4mA supply, and I don't expect to be lower than this on the Barco either.
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Post by Casethecorvetteman on Feb 27, 2016 5:40:37 GMT -5
The Barco is 34.7kV but not sure on current supply ability.
There were some schematics for the Barco splitter floating around somewhere a while ago on another forum. There is a few items in there, nothing complex though.
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Post by gregstv on Feb 27, 2016 6:25:39 GMT -5
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Post by dummyload on Feb 27, 2016 8:34:58 GMT -5
It has been discussed several times that the old and new style splitters or the same and that barco only had put a new parts number on it and could charge more ,but I did some measuring and there is a difference in c value the new style is twice as much value compared to old style I forgot the exact numbers did this few months a go ,you can easily measure the resistor and capacitance in hv splitter you only need an ohm and capacitance meter, so it seems to work interchanging them but I think problems can arise in some cases.
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Post by dummyload on Feb 27, 2016 9:40:27 GMT -5
To rebuilt a splitter we need the hv connectors used in the splitters ,don't know there name and don't know where they can be found because digging out a splitter will be to much work and maybe impossible without distroying the connectors (potting of quad is a lot softer). Sure that splitter and quad can be rebuild when finding these connectors and recycle of the transformer in the quad, hv capacitors and diodes can be found but then for the quad it must fit in the housing ,splitter apropriate housing have to be found and then at last finding the right potting for both. I have never built something at those voltages so maybe I'm way of.
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Post by radiohead314 on Feb 27, 2016 11:55:20 GMT -5
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Post by Casethecorvetteman on Feb 27, 2016 12:27:13 GMT -5
Yeah i remember those pics, i saved them here. Im digging out the rubber from a quad here at the moment to see what the chances of me being able to do a few, if i can get them potted we're laughin  Splitter though is a whole new story, not sure how itd go, may be a start from scratch job. The HV sockets arent a deal killer, there is bound the be other options that can work, then just swap the lead ends to suit. Its the little board on the top of the splitter that im most concerned about, easily removed from another splitter, but will it be correct if it is just installed on another splitter? |
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Post by Casethecorvetteman on Feb 27, 2016 12:34:12 GMT -5
It has been discussed several times that the old and new style splitters or the same and that barco only had put a new parts number on it and could charge more ,but I did some measuring and there is a difference in c value the new style is twice as much value compared to old style I forgot the exact numbers did this few months a go ,you can easily measure the resistor and capacitance in hv splitter you only need an ohm and capacitance meter, so it seems to work interchanging them but I think problems can arise in some cases. I do remember seeing somewhere about capacitance of the different splitters, possibly 3pF and 6pF?? |
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Post by Casethecorvetteman on Feb 27, 2016 12:35:02 GMT -5
Thanks mate  |
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Post by Casethecorvetteman on Feb 27, 2016 12:40:57 GMT -5
Problem with that diagram is there's no values on those internal components!
I can now see a pretty high likely failure point that causes the arcing where the little black wire connects to the little board though. If those capacitors have failed or are being by-passed internally thatll explain it.
Would love to know some values of those internal items.
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Post by dummyload on Feb 27, 2016 16:09:07 GMT -5
The value of c was about 3nf old style and 6nf new style ,I also think those capacitors are the problem, 2 capacitors in serie without a resistor on them to divide he voltage over them is not good but at those voltages resistors are taking alot of space and to keep heat low value have to enormoes ,and they have to be twice the capacitance to ,any unbalance of voltage will tdamage one. Switching the little boards will require readjustment of the trimmer ,most resistors that can handle high voltages that I have seen are not precise. (5 or 10 percent types) . |
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Post by radiohead314 on Feb 27, 2016 18:34:52 GMT -5
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Post by Casethecorvetteman on Feb 27, 2016 19:05:31 GMT -5
The value of c was about 3nf old style and 6nf new style ,I also think those capacitors are the problem, 2 capacitors in serie without a resistor on them to divide he voltage over them is not good but at those voltages resistors are taking alot of space and to keep heat low value have to enormoes ,and they have to be twice the capacitance to ,any unbalance of voltage will tdamage one. Switching the little boards will require readjustment of the trimmer ,most resistors that can handle high voltages that I have seen are not precise. (5 or 10 percent types) . Do you have an adjustment method for that? |
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