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Old June 12th 16, 08:40 PM posted to sci.electronics.repair
John Robertson John Robertson is offline
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Default Flyback replacement on a historical arcade machine.

On 06/11/2016 8:19 AM, Top Cat wrote:
On Thursday, March 24, 2016 at 8:41:39 PM UTC, wrote:
"I think you've hit the nail on the head, in terms of wanting to keep it as original as possible. I realise that may not be possible eventually, but I so want to try. I have bought a converter ready, and tested it but could not for the life of me get an image to show."


I think most of those convertors are designed for NTSC input, and this might not be NTSC. It could be anything.

If you have to retrofit a different fly in there that can be hairy, even scary. The first thing to know is how many pins are used. It may have eight or ten pins, but the less of them used the better. Also look se if there is a focus output, if monochrome it might be automatic focus which gets you off the hook there.

Ideally, there would only be three pins on the bottom connected. If so you got to balance three parameters. One is the pulse width and amplitude for the yoke. Then you have to get the right HV level at the same time. It may require compromises.

If there are scan derived sources off of it the plot thickens. Best to just figure on replacing those sources somehow.

Now, if you get a flyback for it with an open core you can put some windings on it. Either bucking or boosting, or maybe for a supply. I had to put a bucking winding on one a long time ago to match a yoke on a replacement CRT because the yoke native to the chassis would not converge properly. But that was then.

Scan derived sources are not as common in stuff like this as they were in TVs. You might get lucky.

Retrofitting the wrong fly in there can be tricky. You will need a variac.. Also probably a selection of capacitors. And then you might have to install a regulator to get the HV where it needs to be.

In this case, since it is probably reactive scanning, the vertical sweep will tell you when you got it right. You are playing with the horizontal so you can't count on that.

This can be done, it is just a matter of how much time and trouble it will take.


That's super advice and well advanced. I am clearly in over my head. I will start reading and learning more on the subject, before I attempt to fix it. I really do want to keep it original for the sake of preservation. I'm not trying to make a buck or just to play the game. I'm exited to bring it back to life. ...One day.


For a converter you want to get the Composite Video style, not the RGB.
Your game (SI) puts out B&W composite video...

Something like this:

http://www.ebay.com/itm/Tv-Rca-Compo...-/321366580263

John :-#)#

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