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Registered Member #1107
Joined: Thu Nov 08 2007, 10:09PM
Location:
Posts: 792
I got a big screen (front projection) tv the other day and when i took it apart i dident even think of it but this morning i realized that the flyback may be ac because it is feeding the multiplier.
Registered Member #1407
Joined: Fri Mar 21 2008, 07:09AM
Location:
Posts: 222
Hmmm doesnt really look ac, maybe it feeding an extra multiplier beacause that BIG screen needs a BIG voltage, and its easier for a company to buy readily available parts instead of desining a new 100kv flyback
BTW there are some really nice heat sinks in there
Registered Member #1497
Joined: Thu May 22 2008, 05:24AM
Location: Toronto, Ontario, Canada
Posts: 801
I don't think its AC, AC usually are disc shaped iirc. The potted ones with 9 or 11 pins aren't AC. The disc shaped AC ones only have 2 or 3 wires coming out (or at least mine does)
Registered Member #1107
Joined: Thu Nov 08 2007, 10:09PM
Location:
Posts: 792
I have another flyback from a rear projection tv that has 15 pins on it and i know that it is ac. Even the disk shaped flybacks that i have have like 12 pins on it. It still doesent make sense why they would use a dc flyback and connect it to a multiplier/splitter
Registered Member #834
Joined: Tue Jun 12 2007, 10:57PM
Location: Brazil
Posts: 644
If you can measure a resistance between the high-voltage output and the ground, it is AC. Otherwise the rectifying diodes result in a too high voltage drop to allow measurement with a normal ohmmeter. And the resistance is the same in both directions.
Registered Member #1062
Joined: Tue Oct 16 2007, 02:01AM
Location:
Posts: 1529
i think its DC, also, if you just want the core, the halves come right out after being in boiling water with a little pressure. Heatsinks are good too.
Registered Member #1408
Joined: Fri Mar 21 2008, 03:49PM
Location: Oracle, AZ
Posts: 679
You CAN find "modern looking" AC LOPT-flybacks - usually in black & white monitors for CCTV. The key will be a very simplistic constriction with absolutely no adjustments and unfortunately they are rather small. But they do exist aside from the disk shaped classic flyback design.
The cylinder that contains the secondary will be virtually round and won't have anything but ONE the HV lead to the CRT. The addition of the second red lead on your example makes me think that there is some format of rectifier: thus you're not putting out AC.
I know for a fact that B&W CCTV monitors made sold PELCO uses AC flybacks and cost very little. They are often junked by places that use small CCTV monitors in large quantity like casinos. They DO exist. The problem is finding a large one. I have quite a few little ones that I thought of setting up in series. The small ones DO exist They look like the classical DC enclosed flyback that has one HV red lead and NO budging from the secondary and a simple ten pin arraignment..
Most of these use a 12" screen and just don't require the energy to drive them.... hence the small LOPT. Your projection screen dflyback may have enormous potential as a DC flyback as they are usually quite powerful. But to get a modern AC you have to look for a VERY simple B&W monitor.
Registered Member #154
Joined: Sun Feb 12 2006, 04:28PM
Location: Westmidlands, UK
Posts: 260
Hi guys,
Yes....that LOPTX output is rectified, it then feeds a 'splitter' which feeds the EHT three ways for the three CRTS as well as their focus and first anode voltages.
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is this flyback ac?
