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Learning About Flyback Pinout

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LAN_403

D1G1T4L3CH0

Tue Aug 17 2010, 11:39AM

Registered Member #3124 Joined: Tue Aug 17 2010, 10:25AM
Location: 127.0.0.1, US
Posts: 19

I have 3 flybacks, two of which I do not have the pinouts for but I used a method with 9v battery and a DMM on them to find out the the right pins to use. This third one I just got came from a 13" color tv and it's about half as tall as the other two. The thing about this one is that the circuit board it was on has the pinout on it, under the flyback and on the bottom. I don't fully understand what all the pins are for. Of course there are some obvious ones. But to be sure, I used the tried and true method I have used before with the other two flybacks. The pinout I found to be working and I currently have it running with is not what I expected it to be, and with the 0v pin being right next to my negative primary, it arcs constantly to it.

I have some images of the circuit board, I was hoping someone could help me understand what each pin is for (for the purpose of using a 2n2055 transistor driver for it only) so I can wire it up correctly if it's not already. Also, the B+ and 25v pins used to arc some and would get a charge that remained after powered off until i put heat shrink around the positive. The 25v and 12v sometimes arc and get a charge too. I saw another post on here about duct seal...

So here are some images (and video).
Images: Circuit board Top | Circuit board Bottom
Video - Arc-Over: http://tinypic.com/r/amsjl0/4
Video - Action: http://tinypic.com/r/2u5qcza/4

I currently have the following wiring configuration:
GND - negative primary coil
ABL - 0v (idk why it would be on this pin but that's what my testing found...)
25v - positive primary coil

I don't think this is correct, although it works. There are multiple voltage pins, so that leads me to believe that I should use the pin closest to my input voltage (currently 12v), however the testing for the primary with the DMM found only the 25v pin with gnd gave a 1ohm reading. the others were either 1.5ohm or 0.6ohm.

I have some video of it in action as well that shows the problem created when it arcs... Thanks for any help, as I am still learning and glad to have some valuable input..

Adam Munich

Tue Aug 17 2010, 01:23PM

Registered Member #2893 Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242

This is what it should be, but labels are often different on circuit boards.
Your best winding your own primary. That's a big flyback, projection TV?

QRbPw

D1G1T4L3CH0

Tue Aug 17 2010, 02:59PM

Registered Member #3124 Joined: Tue Aug 17 2010, 10:25AM
Location: 127.0.0.1, US
Posts: 19

Nice, thanks for making it pretty clear with the image.

The primary you marked gets 1.3ohms, I just tested it. What would the polarity be? I would imagine the B+ is positive, but since I don't even know what the B stands for I cannot be sure. What does the col stand for, do you know?

I think ABL is auto brightness level or auto black level. Google found automatic frequency control to be AFC. But that doesn't mean anything to me for my purpose I don't think. Would you suggest I use whichever GND or ABL for the HV GND?

I'm pretty sure the heater doesn't matter either right? What exactly would I do with the assorted output voltages? If it's an output, I don't think it would be of use to me, however I am currently using the 25v as an input and it's working. Not sure how. what would the voltage rating be for the input on the primary at COL and B+?

Winding my own primary may be something I'll do at a later time. Actually I guess the flyback looks big in the video, but it's not that big really. Here is another picture of it, and the label.

Have any suggestions for preventing arc over on the pins?

D1G1T4L3CH0

Tue Aug 17 2010, 05:25PM

Registered Member #3124 Joined: Tue Aug 17 2010, 10:25AM
Location: 127.0.0.1, US
Posts: 19

Update: I just tried using the primary (COL and B+). It works but not very well. I get less than half the spark length (maybe 1/4 the length) and it sounds as if the frequency is much higher. All that was done is the positive and negative wires were moved from pins GND and 25v to COL and B+. I wired the negative to COL and positive to B+. I was using the ABL pin as before for the hv return but I also tried the gnd.

Proud Mary

Tue Aug 17 2010, 07:57PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Here is the data sheet for HR Diemen's part HR8823 manufactured as a replacement part for your FCK-14B025A.

You will note a primary voltage of 110V (a common standard nowadays) tapped half way at 55V.

As you will see from the data set, this diode-split LOPT is designed for an EHT output of 25.5kV/2mA.

LOPT designers compete with eachother to make the transformer do as much work as possible - as you'll see from the outputs available on
pins 3,4,5, 9, and 10 which provide power to other subsystems.

D1G1T4L3CH0

Wed Aug 18 2010, 03:34AM

Registered Member #3124 Joined: Tue Aug 17 2010, 10:25AM
Location: 127.0.0.1, US
Posts: 19

Proud Mary, the datasheet you provided may be the replacement for the transformer I have however the pinout is a bit different... I'm guessing the COL and B+ are 125v though and since it's Vcc, I should probably not be trying to send pulsed voltage to it. But some questions previously asked still remain. Maybe I should just ask, "How would you hook up a single transistor driver to this flyback?". Thanks.

Proud Mary

Wed Aug 18 2010, 10:24AM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

D1G1T4L3CH0 wrote ...

Proud Mary, the datasheet you provided may be the replacement for the transformer I have however the pinout is a bit different... I'm guessing the COL and B+ are 125v though and since it's Vcc, I should probably not be trying to send pulsed voltage to it. But some questions previously asked still remain. Maybe I should just ask, "How would you hook up a single transistor driver to this flyback?". Thanks.

HR Diemen is the world's leading manufacturer of like-for-like replacement LOPT parts, so I would be surprised if their HR8823 was not pin compatible with FCK-14B025A and 3214029, since that would completely defeat the purpose of manufacturing it. A 'replacement' which was not pin-for-pin equivalent would be entirely useless in
normal television servicing and repair.

The fact that your LOPT has stamped upon it both FCK-14B025A and 3214029 suggests to me that it is not an OEM part, but is itself a replacement part.

Here is the listing in the HR product catalogue, showing their own LOPT test meter, to which the figures in the datasheet table relate:

As for how you might best wire it up for use with a single transistor, nearly all the arcs-n-sparks boys wind on a new primary of ten turns or so, as Grenadier suggests above.

You'll find endless discussions of this type of circuit, and ways of improving it, in other forum threads.

Enjoy!

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